Augments hugetlb_cgroup_charge_cgroup to be able to charge hugetlb usage or hugetlb reservation counter.

Adds a new interface to uncharge a hugetlb_cgroup counter via hugetlb_cgroup_uncharge_counter.

Integrates the counter with hugetlb_cgroup, via hugetlb_cgroup_init, hugetlb_cgroup_have_usage, and hugetlb_cgroup_css_offline.

Signed-off-by: Mina Almasry almasrymina@google.com

---

Changes in v12: - Instead of true/false param for rsvd or non-rsvd calls, now there is: hugetlb_cgroup_*() call for non-rsvd hugetlb_cgroup_*_rsvd() call for rsvd __hugetlb_cgroup_*(, bool) for both. - Removed review tags as this patch changed quite a bit.

Changes in v11: - Changed all 'reserved' or 'reservation' to 'rsvd' to reflect the user interface. - Expanded comment that describes tail pages usage. facing naming.

Changes in v10: - Added missing VM_BUG_ON

Changes in V9: - Fixed HUGETLB_CGROUP_MIN_ORDER. - Minor variable name update. - Moved some init/cleanup code from later patches in the series to this patch. - Updated reparenting of reservation accounting.

--- include/linux/hugetlb_cgroup.h | 123 +++++++++++++++++++---- mm/hugetlb.c | 2 + mm/hugetlb_cgroup.c | 174 +++++++++++++++++++++++++++------ 3 files changed, 251 insertions(+), 48 deletions(-)

diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h index 063962f6dfc6a..5443f4548d523 100644 --- a/include/linux/hugetlb_cgroup.h +++ b/include/linux/hugetlb_cgroup.h @@ -20,32 +20,64 @@ struct hugetlb_cgroup; /* * Minimum page order trackable by hugetlb cgroup. - * At least 3 pages are necessary for all the tracking information. + * At least 4 pages are necessary for all the tracking information. + * The second tail page (hpage[2]) is the fault usage cgroup. + * The third tail page (hpage[3]) is the reservation usage cgroup. */ #define HUGETLB_CGROUP_MIN_ORDER 2

#ifdef CONFIG_CGROUP_HUGETLB

-static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page) +static inline struct hugetlb_cgroup * +__hugetlb_cgroup_from_page(struct page *page, bool rsvd) { VM_BUG_ON_PAGE(!PageHuge(page), page);

if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER) return NULL; - return (struct hugetlb_cgroup *)page[2].private; + if (rsvd) + return (struct hugetlb_cgroup *)page[3].private; + else + return (struct hugetlb_cgroup *)page[2].private; +} + +static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page) +{ + return __hugetlb_cgroup_from_page(page, false); }

-static inline -int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg) +static inline struct hugetlb_cgroup * +hugetlb_cgroup_from_page_rsvd(struct page *page) +{ + return __hugetlb_cgroup_from_page(page, true); +} + +static inline int __set_hugetlb_cgroup(struct page *page, + struct hugetlb_cgroup *h_cg, bool rsvd) { VM_BUG_ON_PAGE(!PageHuge(page), page);

if (compound_order(page) < HUGETLB_CGROUP_MIN_ORDER) return -1; - page[2].private = (unsigned long)h_cg; + if (rsvd) + page[3].private = (unsigned long)h_cg; + else + page[2].private = (unsigned long)h_cg; return 0; }

+static inline int set_hugetlb_cgroup(struct page *page, + struct hugetlb_cgroup *h_cg) +{ + return __set_hugetlb_cgroup(page, h_cg, false); +} + +static inline int set_hugetlb_cgroup_rsvd(struct page *page, + struct hugetlb_cgroup *h_cg) +{ + return __set_hugetlb_cgroup(page, h_cg, true); +} + static inline bool hugetlb_cgroup_disabled(void) { return !cgroup_subsys_enabled(hugetlb_cgrp_subsys); @@ -53,13 +85,27 @@ static inline bool hugetlb_cgroup_disabled(void)

extern int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, struct hugetlb_cgroup **ptr); +extern int hugetlb_cgroup_charge_cgroup_rsvd(int idx, unsigned long nr_pages, + struct hugetlb_cgroup **ptr); extern void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages, struct hugetlb_cgroup *h_cg, struct page *page); +extern void hugetlb_cgroup_commit_charge_rsvd(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg, + struct page *page); extern void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, struct page *page); +extern void hugetlb_cgroup_uncharge_page_rsvd(int idx, unsigned long nr_pages, + struct page *page); + extern void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, struct hugetlb_cgroup *h_cg); +extern void hugetlb_cgroup_uncharge_cgroup_rsvd(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg); +extern void hugetlb_cgroup_uncharge_counter(struct page_counter *p, + unsigned long nr_pages, + struct cgroup_subsys_state *css); + extern void hugetlb_cgroup_file_init(void) __init; extern void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage); @@ -70,8 +116,26 @@ static inline struct hugetlb_cgroup *hugetlb_cgroup_from_page(struct page *page) return NULL; }

-static inline -int set_hugetlb_cgroup(struct page *page, struct hugetlb_cgroup *h_cg) +static inline struct hugetlb_cgroup * +hugetlb_cgroup_from_page_resv(struct page *page) +{ + return NULL; +} + +static inline struct hugetlb_cgroup * +hugetlb_cgroup_from_page_rsvd(struct page *page) +{ + return NULL; +} + +static inline int set_hugetlb_cgroup(struct page *page, + struct hugetlb_cgroup *h_cg) +{ + return 0; +} + +static inline int set_hugetlb_cgroup_rsvd(struct page *page, + struct hugetlb_cgroup *h_cg) { return 0; } @@ -81,28 +145,51 @@ static inline bool hugetlb_cgroup_disabled(void) return true; }

-static inline int -hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, - struct hugetlb_cgroup **ptr) +static inline int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, + struct hugetlb_cgroup **ptr) { return 0; }

-static inline void -hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages, - struct hugetlb_cgroup *h_cg, - struct page *page) +static inline int hugetlb_cgroup_charge_cgroup_rsvd(int idx, + unsigned long nr_pages, + struct hugetlb_cgroup **ptr) +{ + return 0; +} + +static inline void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg, + struct page *page) { }

static inline void -hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, struct page *page) +hugetlb_cgroup_commit_charge_rsvd(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg, + struct page *page) +{ +} + +static inline void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, + struct page *page) +{ +} + +static inline void hugetlb_cgroup_uncharge_page_rsvd(int idx, + unsigned long nr_pages, + struct page *page) +{ +} +static inline void hugetlb_cgroup_uncharge_cgroup(int idx, + unsigned long nr_pages, + struct hugetlb_cgroup *h_cg) { }

static inline void -hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, - struct hugetlb_cgroup *h_cg) +hugetlb_cgroup_uncharge_cgroup_rsvd(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg) { }

diff --git a/mm/hugetlb.c b/mm/hugetlb.c index dd8737a94bec4..357817e33fb34 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1069,6 +1069,7 @@ static void update_and_free_page(struct hstate *h, struct page *page) 1 << PG_writeback); } VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page); set_compound_page_dtor(page, NULL_COMPOUND_DTOR); set_page_refcounted(page); if (hstate_is_gigantic(h)) { @@ -1254,6 +1255,7 @@ static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) set_compound_page_dtor(page, HUGETLB_PAGE_DTOR); spin_lock(&hugetlb_lock); set_hugetlb_cgroup(page, NULL); + set_hugetlb_cgroup_rsvd(page, NULL); h->nr_huge_pages++; h->nr_huge_pages_node[nid]++; spin_unlock(&hugetlb_lock); diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index 08b2adcdb5c1c..b8246389fb153 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -61,14 +61,26 @@ struct hugetlb_cgroup { static struct hugetlb_cgroup *root_h_cgroup __read_mostly;

static inline struct page_counter * -hugetlb_cgroup_counter_from_cgroup(struct hugetlb_cgroup *h_cg, int idx, - bool rsvd) +__hugetlb_cgroup_counter_from_cgroup(struct hugetlb_cgroup *h_cg, int idx, + bool rsvd) { if (rsvd) return &h_cg->rsvd_hugepage[idx]; return &h_cg->hugepage[idx]; }

+static inline struct page_counter * +hugetlb_cgroup_counter_from_cgroup(struct hugetlb_cgroup *h_cg, int idx) +{ + return __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, false); +} + +static inline struct page_counter * +hugetlb_cgroup_counter_from_cgroup_rsvd(struct hugetlb_cgroup *h_cg, int idx) +{ + return __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, true); +} + static inline struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s) { @@ -97,8 +109,12 @@ static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg) int idx;

for (idx = 0; idx < hugetlb_max_hstate; idx++) { - if (page_counter_read(&h_cg->hugepage[idx])) + if (page_counter_read( + hugetlb_cgroup_counter_from_cgroup(h_cg, idx)) || + page_counter_read(hugetlb_cgroup_counter_from_cgroup_rsvd( + h_cg, idx))) { return true; + } } return false; } @@ -109,18 +125,34 @@ static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup, int idx;

for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) { - struct page_counter *counter = &h_cgroup->hugepage[idx]; - struct page_counter *parent = NULL; + struct page_counter *fault_parent = NULL; + struct page_counter *rsvd_parent = NULL; unsigned long limit; int ret;

- if (parent_h_cgroup) - parent = &parent_h_cgroup->hugepage[idx]; - page_counter_init(counter, parent); + if (parent_h_cgroup) { + fault_parent = hugetlb_cgroup_counter_from_cgroup( + parent_h_cgroup, idx); + rsvd_parent = hugetlb_cgroup_counter_from_cgroup_rsvd( + parent_h_cgroup, idx); + } + page_counter_init(hugetlb_cgroup_counter_from_cgroup(h_cgroup, + idx), + fault_parent); + page_counter_init( + hugetlb_cgroup_counter_from_cgroup_rsvd(h_cgroup, idx), + rsvd_parent);

limit = round_down(PAGE_COUNTER_MAX, 1 << huge_page_order(&hstates[idx])); - ret = page_counter_set_max(counter, limit); + + ret = page_counter_set_max( + hugetlb_cgroup_counter_from_cgroup(h_cgroup, idx), + limit); + VM_BUG_ON(ret); + ret = page_counter_set_max( + hugetlb_cgroup_counter_from_cgroup_rsvd(h_cgroup, idx), + limit); VM_BUG_ON(ret); } } @@ -150,7 +182,6 @@ static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css) kfree(h_cgroup); }

- /* * Should be called with hugetlb_lock held. * Since we are holding hugetlb_lock, pages cannot get moved from @@ -227,8 +258,9 @@ static inline void hugetlb_event(struct hugetlb_cgroup *hugetlb, int idx, !hugetlb_cgroup_is_root(hugetlb)); }

-int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, - struct hugetlb_cgroup **ptr) +static int __hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, + struct hugetlb_cgroup **ptr, + bool rsvd) { int ret = 0; struct page_counter *counter; @@ -251,51 +283,104 @@ int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, } rcu_read_unlock();

- if (!page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, - &counter)) { + if (!page_counter_try_charge( + __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd), + nr_pages, &counter)) { ret = -ENOMEM; hugetlb_event(hugetlb_cgroup_from_counter(counter, idx), idx, HUGETLB_MAX); + css_put(&h_cg->css); + goto done; } - css_put(&h_cg->css); + /* Reservations take a reference to the css because they do not get + * reparented. + */ + if (!rsvd) + css_put(&h_cg->css); done: *ptr = h_cg; return ret; }

+int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, + struct hugetlb_cgroup **ptr) +{ + return __hugetlb_cgroup_charge_cgroup(idx, nr_pages, ptr, false); +} + +int hugetlb_cgroup_charge_cgroup_rsvd(int idx, unsigned long nr_pages, + struct hugetlb_cgroup **ptr) +{ + return __hugetlb_cgroup_charge_cgroup(idx, nr_pages, ptr, true); +} + /* Should be called with hugetlb_lock held */ -void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages, - struct hugetlb_cgroup *h_cg, - struct page *page) +static void __hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg, + struct page *page, bool rsvd) { if (hugetlb_cgroup_disabled() || !h_cg) return;

- set_hugetlb_cgroup(page, h_cg); + __set_hugetlb_cgroup(page, h_cg, rsvd); return; }

+void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg, + struct page *page) +{ + __hugetlb_cgroup_commit_charge(idx, nr_pages, h_cg, page, false); +} + +void hugetlb_cgroup_commit_charge_rsvd(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg, + struct page *page) +{ + __hugetlb_cgroup_commit_charge(idx, nr_pages, h_cg, page, true); +} + /* * Should be called with hugetlb_lock held */ -void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, - struct page *page) +static void __hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, + struct page *page, bool rsvd) { struct hugetlb_cgroup *h_cg;

if (hugetlb_cgroup_disabled()) return; lockdep_assert_held(&hugetlb_lock); - h_cg = hugetlb_cgroup_from_page(page); + h_cg = __hugetlb_cgroup_from_page(page, rsvd); if (unlikely(!h_cg)) return; - set_hugetlb_cgroup(page, NULL); - page_counter_uncharge(&h_cg->hugepage[idx], nr_pages); + __set_hugetlb_cgroup(page, NULL, rsvd); + + page_counter_uncharge(__hugetlb_cgroup_counter_from_cgroup(h_cg, idx, + rsvd), + nr_pages); + + if (rsvd) + css_put(&h_cg->css); + return; }

-void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, - struct hugetlb_cgroup *h_cg) +void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, + struct page *page) +{ + __hugetlb_cgroup_uncharge_page(idx, nr_pages, page, false); +} + +void hugetlb_cgroup_uncharge_page_rsvd(int idx, unsigned long nr_pages, + struct page *page) +{ + __hugetlb_cgroup_uncharge_page(idx, nr_pages, page, true); +} + +static void __hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg, + bool rsvd) { if (hugetlb_cgroup_disabled() || !h_cg) return; @@ -303,8 +388,35 @@ void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER) return;

- page_counter_uncharge(&h_cg->hugepage[idx], nr_pages); - return; + page_counter_uncharge(__hugetlb_cgroup_counter_from_cgroup(h_cg, idx, + rsvd), + nr_pages); + + if (rsvd) + css_put(&h_cg->css); +} + +void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg) +{ + __hugetlb_cgroup_uncharge_cgroup(idx, nr_pages, h_cg, false); +} + +void hugetlb_cgroup_uncharge_cgroup_rsvd(int idx, unsigned long nr_pages, + struct hugetlb_cgroup *h_cg) +{ + __hugetlb_cgroup_uncharge_cgroup(idx, nr_pages, h_cg, true); +} + +void hugetlb_cgroup_uncharge_counter(struct page_counter *p, + unsigned long nr_pages, + struct cgroup_subsys_state *css) +{ + if (hugetlb_cgroup_disabled() || !p || !css) + return; + + page_counter_uncharge(p, nr_pages); + css_put(css); }

enum { @@ -419,7 +531,7 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of, case RES_LIMIT: mutex_lock(&hugetlb_limit_mutex); ret = page_counter_set_max( - hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd), + __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd), nr_pages); mutex_unlock(&hugetlb_limit_mutex); break; @@ -675,6 +787,7 @@ void __init hugetlb_cgroup_file_init(void) void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage) { struct hugetlb_cgroup *h_cg; + struct hugetlb_cgroup *h_cg_rsvd; struct hstate *h = page_hstate(oldhpage);

if (hugetlb_cgroup_disabled()) @@ -683,10 +796,11 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage) VM_BUG_ON_PAGE(!PageHuge(oldhpage), oldhpage); spin_lock(&hugetlb_lock); h_cg = hugetlb_cgroup_from_page(oldhpage); + h_cg_rsvd = hugetlb_cgroup_from_page_rsvd(oldhpage); set_hugetlb_cgroup(oldhpage, NULL);

/* move the h_cg details to new cgroup */ - set_hugetlb_cgroup(newhpage, h_cg); + set_hugetlb_cgroup_rsvd(newhpage, h_cg_rsvd); list_move(&newhpage->lru, &h->hugepage_activelist); spin_unlock(&hugetlb_lock); return; -- 2.25.0.225.g125e21ebc7-goog

A follow up patch in this series adds hugetlb cgroup uncharge info the file_region entries in resv->regions. The cgroup uncharge info may differ for different regions, so they can no longer be coalesced at region_add time. So, disable region coalescing in region_add in this patch.

Behavior change:

Say a resv_map exists like this [0->1], [2->3], and [5->6].

Then a region_chg/add call comes in region_chg/add(f=0, t=5).

Old code would generate resv->regions: [0->5], [5->6]. New code would generate resv->regions: [0->1], [1->2], [2->3], [3->5], [5->6].

Special care needs to be taken to handle the resv->adds_in_progress variable correctly. In the past, only 1 region would be added for every region_chg and region_add call. But now, each call may add multiple regions, so we can no longer increment adds_in_progress by 1 in region_chg, or decrement adds_in_progress by 1 after region_add or region_abort. Instead, region_chg calls add_reservation_in_range() to count the number of regions needed and allocates those, and that info is passed to region_add and region_abort to decrement adds_in_progress correctly.

We've also modified the assumption that region_add after region_chg never fails. region_chg now pre-allocates at least 1 region for region_add. If region_add needs more regions than region_chg has allocated for it, then it may fail.

Signed-off-by: Mina Almasry almasrymina@google.com

---

Changes in v12: - Removed Mike's Reviewed-by until coalescing is reviewed per his request. - Added VM_BUG_ON that was mistakingly in a follow up patch.

Changes in v9: - Added clarifications in the comments and addressed minor issues from code review.

Changes in v7: - region_chg no longer allocates (t-f) / 2 file_region entries.

Changes in v6: - Fix bug in number of region_caches allocated by region_chg

--- mm/hugetlb.c | 328 +++++++++++++++++++++++++++++++++++---------------- 1 file changed, 224 insertions(+), 104 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ac7bab0afafe7..57739e1aedeca 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -245,110 +245,180 @@ struct file_region { long to; };

+/* Helper that removes a struct file_region from the resv_map cache and returns + * it for use. + */ +static struct file_region * +get_file_region_entry_from_cache(struct resv_map *resv, long from, long to) +{ + struct file_region *nrg = NULL; + + VM_BUG_ON(resv->region_cache_count <= 0); + + resv->region_cache_count--; + nrg = list_first_entry(&resv->region_cache, struct file_region, link); + VM_BUG_ON(!nrg); + list_del(&nrg->link); + + nrg->from = from; + nrg->to = to; + + return nrg; +} + /* Must be called with resv->lock held. Calling this with count_only == true * will count the number of pages to be added but will not modify the linked - * list. + * list. If regions_needed != NULL and count_only == true, then regions_needed + * will indicate the number of file_regions needed in the cache to carry out to + * add the regions for this range. */ static long add_reservation_in_range(struct resv_map *resv, long f, long t, - bool count_only) + long *regions_needed, bool count_only) { - long chg = 0; + long add = 0; struct list_head *head = &resv->regions; + long last_accounted_offset = f; struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;

- /* Locate the region we are before or in. */ - list_for_each_entry(rg, head, link) - if (f <= rg->to) - break; - - /* Round our left edge to the current segment if it encloses us. */ - if (f > rg->from) - f = rg->from; + if (regions_needed) + *regions_needed = 0;

- chg = t - f; + /* In this loop, we essentially handle an entry for the range + * [last_accounted_offset, rg->from), at every iteration, with some + * bounds checking. + */ + list_for_each_entry_safe(rg, trg, head, link) { + /* Skip irrelevant regions that start before our range. */ + if (rg->from < f) { + /* If this region ends after the last accounted offset, + * then we need to update last_accounted_offset. + */ + if (rg->to > last_accounted_offset) + last_accounted_offset = rg->to; + continue; + }

- /* Check for and consume any regions we now overlap with. */ - nrg = rg; - list_for_each_entry_safe(rg, trg, rg->link.prev, link) { - if (&rg->link == head) - break; + /* When we find a region that starts beyond our range, we've + * finished. + */ if (rg->from > t) break;

- /* We overlap with this area, if it extends further than - * us then we must extend ourselves. Account for its - * existing reservation. + /* Add an entry for last_accounted_offset -> rg->from, and + * update last_accounted_offset. */ - if (rg->to > t) { - chg += rg->to - t; - t = rg->to; + if (rg->from > last_accounted_offset) { + add += rg->from - last_accounted_offset; + if (!count_only) { + nrg = get_file_region_entry_from_cache( + resv, last_accounted_offset, rg->from); + list_add(&nrg->link, rg->link.prev); + } else if (regions_needed) + *regions_needed += 1; } - chg -= rg->to - rg->from;

- if (!count_only && rg != nrg) { - list_del(&rg->link); - kfree(rg); - } + last_accounted_offset = rg->to; }

- if (!count_only) { - nrg->from = f; - nrg->to = t; + /* Handle the case where our range extends beyond + * last_accounted_offset. + */ + if (last_accounted_offset < t) { + add += t - last_accounted_offset; + if (!count_only) { + nrg = get_file_region_entry_from_cache( + resv, last_accounted_offset, t); + list_add(&nrg->link, rg->link.prev); + } else if (regions_needed) + *regions_needed += 1; }

- return chg; + VM_BUG_ON(add < 0); + return add; }

/* * Add the huge page range represented by [f, t) to the reserve - * map. Existing regions will be expanded to accommodate the specified - * range, or a region will be taken from the cache. Sufficient regions - * must exist in the cache due to the previous call to region_chg with - * the same range. + * map. Regions will be taken from the cache to fill in this range. + * Sufficient regions should exist in the cache due to the previous + * call to region_chg with the same range, but in some cases the cache will not + * have sufficient entries due to races with other code doing region_add or + * region_del. The extra needed entries will be allocated. + * + * regions_needed is the out value provided by a previous call to region_chg. * - * Return the number of new huge pages added to the map. This - * number is greater than or equal to zero. + * Return the number of new huge pages added to the map. This number is greater + * than or equal to zero. If file_region entries needed to be allocated for + * this operation and we were not able to allocate, it ruturns -ENOMEM. + * region_add of regions of length 1 never allocate file_regions and cannot + * fail; region_chg will always allocate at least 1 entry and a region_add for + * 1 page will only require at most 1 entry. */ -static long region_add(struct resv_map *resv, long f, long t) +static long region_add(struct resv_map *resv, long f, long t, + long in_regions_needed) { - struct list_head *head = &resv->regions; - struct file_region *rg, *nrg; - long add = 0; + long add = 0, actual_regions_needed = 0, i = 0; + struct file_region *trg = NULL, *rg = NULL; + struct list_head allocated_regions; + + INIT_LIST_HEAD(&allocated_regions);

spin_lock(&resv->lock); - /* Locate the region we are either in or before. */ - list_for_each_entry(rg, head, link) - if (f <= rg->to) - break; +retry: + + /* Count how many regions are actually needed to execute this add. */ + add_reservation_in_range(resv, f, t, &actual_regions_needed, true);

/* - * If no region exists which can be expanded to include the - * specified range, pull a region descriptor from the cache - * and use it for this range. + * Check for sufficient descriptors in the cache to accommodate + * this add operation. Note that actual_regions_needed may be greater + * than in_regions_needed. In this case, we need to make sure that we + * allocate extra entries, such that we have enough for all the + * existing adds_in_progress, plus the excess needed for this + * operation. */ - if (&rg->link == head || t < rg->from) { - VM_BUG_ON(resv->region_cache_count <= 0); + if (resv->region_cache_count < + resv->adds_in_progress + + (actual_regions_needed - in_regions_needed)) { + /* region_add operation of range 1 should never need to + * allocate file_region entries. + */ + VM_BUG_ON(t - f <= 1);

- resv->region_cache_count--; - nrg = list_first_entry(&resv->region_cache, struct file_region, - link); - list_del(&nrg->link); + /* Must drop lock to allocate a new descriptor. */ + spin_unlock(&resv->lock); + for (i = 0; i < (actual_regions_needed - in_regions_needed); + i++) { + trg = kmalloc(sizeof(*trg), GFP_KERNEL); + if (!trg) + goto out_of_memory; + list_add(&trg->link, &allocated_regions); + } + spin_lock(&resv->lock);

- nrg->from = f; - nrg->to = t; - list_add(&nrg->link, rg->link.prev); + list_for_each_entry_safe(rg, trg, &allocated_regions, link) { + list_del(&rg->link); + list_add(&rg->link, &resv->region_cache); + resv->region_cache_count++; + }

- add += t - f; - goto out_locked; + goto retry; }

- add = add_reservation_in_range(resv, f, t, false); + add = add_reservation_in_range(resv, f, t, NULL, false); + + resv->adds_in_progress -= in_regions_needed;

-out_locked: - resv->adds_in_progress--; spin_unlock(&resv->lock); VM_BUG_ON(add < 0); return add; + +out_of_memory: + list_for_each_entry_safe(rg, trg, &allocated_regions, link) { + list_del(&rg->link); + kfree(rg); + } + return -ENOMEM; }

/* @@ -358,49 +428,79 @@ static long region_add(struct resv_map *resv, long f, long t) * call to region_add that will actually modify the reserve * map to add the specified range [f, t). region_chg does * not change the number of huge pages represented by the - * map. A new file_region structure is added to the cache - * as a placeholder, so that the subsequent region_add - * call will have all the regions it needs and will not fail. + * map. A number of new file_region structures is added to the cache as a + * placeholder, for the subsequent region_add call to use. At least 1 + * file_region structure is added. + * + * out_regions_needed is the number of regions added to the + * resv->adds_in_progress. This value needs to be provided to a follow up call + * to region_add or region_abort for proper accounting. * * Returns the number of huge pages that need to be added to the existing * reservation map for the range [f, t). This number is greater or equal to * zero. -ENOMEM is returned if a new file_region structure or cache entry * is needed and can not be allocated. */ -static long region_chg(struct resv_map *resv, long f, long t) +static long region_chg(struct resv_map *resv, long f, long t, + long *out_regions_needed) { - long chg = 0; + struct file_region *trg = NULL, *rg = NULL; + long chg = 0, i = 0, to_allocate = 0; + struct list_head allocated_regions; + + INIT_LIST_HEAD(&allocated_regions);

spin_lock(&resv->lock); -retry_locked: - resv->adds_in_progress++; + + /* Count how many hugepages in this range are NOT respresented. */ + chg = add_reservation_in_range(resv, f, t, out_regions_needed, true); + + if (*out_regions_needed == 0) + *out_regions_needed = 1; + + resv->adds_in_progress += *out_regions_needed;

/* * Check for sufficient descriptors in the cache to accommodate * the number of in progress add operations. */ - if (resv->adds_in_progress > resv->region_cache_count) { - struct file_region *trg; - - VM_BUG_ON(resv->adds_in_progress - resv->region_cache_count > 1); - /* Must drop lock to allocate a new descriptor. */ - resv->adds_in_progress--; + while (resv->region_cache_count < resv->adds_in_progress) { + to_allocate = resv->adds_in_progress - resv->region_cache_count; + + /* Must drop lock to allocate a new descriptor. Note that even + * though we drop the lock here, we do not make another call to + * add_reservation_in_range after re-acquiring the lock. + * Essentially this branch makes sure that we have enough + * descriptors in the cache as suggested by the first call to + * add_reservation_in_range. If more regions turn out to be + * required, region_add will deal with it. + */ spin_unlock(&resv->lock); - - trg = kmalloc(sizeof(*trg), GFP_KERNEL); - if (!trg) - return -ENOMEM; + for (i = 0; i < to_allocate; i++) { + trg = kmalloc(sizeof(*trg), GFP_KERNEL); + if (!trg) + goto out_of_memory; + list_add(&trg->link, &allocated_regions); + }

spin_lock(&resv->lock); - list_add(&trg->link, &resv->region_cache); - resv->region_cache_count++; - goto retry_locked; - }

- chg = add_reservation_in_range(resv, f, t, true); + list_for_each_entry_safe(rg, trg, &allocated_regions, link) { + list_del(&rg->link); + list_add(&rg->link, &resv->region_cache); + resv->region_cache_count++; + } + }

spin_unlock(&resv->lock); return chg; + +out_of_memory: + list_for_each_entry_safe(rg, trg, &allocated_regions, link) { + list_del(&rg->link); + kfree(rg); + } + return -ENOMEM; }

/* @@ -408,17 +508,20 @@ static long region_chg(struct resv_map *resv, long f, long t) * of the resv_map keeps track of the operations in progress between * calls to region_chg and region_add. Operations are sometimes * aborted after the call to region_chg. In such cases, region_abort - * is called to decrement the adds_in_progress counter. + * is called to decrement the adds_in_progress counter. regions_needed + * is the value returned by the region_chg call, it is used to decrement + * the adds_in_progress counter. * * NOTE: The range arguments [f, t) are not needed or used in this * routine. They are kept to make reading the calling code easier as * arguments will match the associated region_chg call. */ -static void region_abort(struct resv_map *resv, long f, long t) +static void region_abort(struct resv_map *resv, long f, long t, + long regions_needed) { spin_lock(&resv->lock); VM_BUG_ON(!resv->region_cache_count); - resv->adds_in_progress--; + resv->adds_in_progress -= regions_needed; spin_unlock(&resv->lock); }

@@ -1898,6 +2001,7 @@ static long __vma_reservation_common(struct hstate *h, struct resv_map *resv; pgoff_t idx; long ret; + long dummy_out_regions_needed;

resv = vma_resv_map(vma); if (!resv) @@ -1906,20 +2010,29 @@ static long __vma_reservation_common(struct hstate *h, idx = vma_hugecache_offset(h, vma, addr); switch (mode) { case VMA_NEEDS_RESV: - ret = region_chg(resv, idx, idx + 1); + ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed); + /* We assume that vma_reservation_* routines always operate on + * 1 page, and that adding to resv map a 1 page entry can only + * ever require 1 region. + */ + VM_BUG_ON(dummy_out_regions_needed != 1); break; case VMA_COMMIT_RESV: - ret = region_add(resv, idx, idx + 1); + ret = region_add(resv, idx, idx + 1, 1); + /* region_add calls of range 1 should never fail. */ + VM_BUG_ON(ret < 0); break; case VMA_END_RESV: - region_abort(resv, idx, idx + 1); + region_abort(resv, idx, idx + 1, 1); ret = 0; break; case VMA_ADD_RESV: - if (vma->vm_flags & VM_MAYSHARE) - ret = region_add(resv, idx, idx + 1); - else { - region_abort(resv, idx, idx + 1); + if (vma->vm_flags & VM_MAYSHARE) { + ret = region_add(resv, idx, idx + 1, 1); + /* region_add calls of range 1 should never fail. */ + VM_BUG_ON(ret < 0); + } else { + region_abort(resv, idx, idx + 1, 1); ret = region_del(resv, idx, idx + 1); } break; @@ -4569,12 +4682,12 @@ int hugetlb_reserve_pages(struct inode *inode, struct vm_area_struct *vma, vm_flags_t vm_flags) { - long ret, chg; + long ret, chg, add = -1; struct hstate *h = hstate_inode(inode); struct hugepage_subpool *spool = subpool_inode(inode); struct resv_map *resv_map; struct hugetlb_cgroup *h_cg; - long gbl_reserve; + long gbl_reserve, regions_needed = 0;

/* This should never happen */ if (from > to) { @@ -4604,7 +4717,7 @@ int hugetlb_reserve_pages(struct inode *inode, */ resv_map = inode_resv_map(inode);

- chg = region_chg(resv_map, from, to); + chg = region_chg(resv_map, from, to, &regions_needed);

} else { /* Private mapping. */ @@ -4670,9 +4783,14 @@ int hugetlb_reserve_pages(struct inode *inode, * else has to be done for private mappings here */ if (!vma || vma->vm_flags & VM_MAYSHARE) { - long add = region_add(resv_map, from, to); - - if (unlikely(chg > add)) { + add = region_add(resv_map, from, to, regions_needed); + + if (unlikely(add < 0)) { + hugetlb_acct_memory(h, -gbl_reserve); + /* put back original number of pages, chg */ + (void)hugepage_subpool_put_pages(spool, chg); + goto out_err; + } else if (unlikely(chg > add)) { /* * pages in this range were added to the reserve * map between region_chg and region_add. This @@ -4690,9 +4808,11 @@ int hugetlb_reserve_pages(struct inode *inode, return 0; out_err: if (!vma || vma->vm_flags & VM_MAYSHARE) - /* Don't call region_abort if region_chg failed */ - if (chg >= 0) - region_abort(resv_map, from, to); + /* Only call region_abort if the region_chg succeeded but the + * region_add failed or didn't run. + */ + if (chg >= 0 && add < 0) + region_abort(resv_map, from, to, regions_needed); if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) kref_put(&resv_map->refs, resv_map_release); return ret; -- 2.25.0.225.g125e21ebc7-goog

Support MAP_NORESERVE accounting as part of the new counter.

For each hugepage allocation, at allocation time we check if there is a reservation for this allocation or not. If there is a reservation for this allocation, then this allocation was charged at reservation time, and we don't re-account it. If there is no reserevation for this allocation, we charge the appropriate hugetlb_cgroup.

The hugetlb_cgroup to uncharge for this allocation is stored in page[3].private. We use new APIs added in an earlier patch to set this pointer.

Signed-off-by: Mina Almasry almasrymina@google.com

---

Changes in v12: - Minor rebase to new interface for readability.

Changes in v10: - Refactored deferred_reserve check.

--- mm/hugetlb.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c index a9171c3cbed6b..2d62dd35399db 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1342,6 +1342,8 @@ static void __free_huge_page(struct page *page) clear_page_huge_active(page); hugetlb_cgroup_uncharge_page(hstate_index(h), pages_per_huge_page(h), page); + hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h), + pages_per_huge_page(h), page); if (restore_reserve) h->resv_huge_pages++;

@@ -2175,6 +2177,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, long gbl_chg; int ret, idx; struct hugetlb_cgroup *h_cg; + bool deferred_reserve;

idx = hstate_index(h); /* @@ -2212,9 +2215,19 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, gbl_chg = 1; }

+ /* If this allocation is not consuming a reservation, charge it now. + */ + deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma); + if (deferred_reserve) { + ret = hugetlb_cgroup_charge_cgroup_rsvd( + idx, pages_per_huge_page(h), &h_cg); + if (ret) + goto out_subpool_put; + } + ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); if (ret) - goto out_subpool_put; + goto out_uncharge_cgroup_reservation;

spin_lock(&hugetlb_lock); /* @@ -2237,6 +2250,14 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, /* Fall through */ } hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); + /* If allocation is not consuming a reservation, also store the + * hugetlb_cgroup pointer on the page. + */ + if (deferred_reserve) { + hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h), + h_cg, page); + } + spin_unlock(&hugetlb_lock);

set_page_private(page, (unsigned long)spool); @@ -2261,6 +2282,10 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,

out_uncharge_cgroup: hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); +out_uncharge_cgroup_reservation: + if (deferred_reserve) + hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h), + h_cg); out_subpool_put: if (map_chg || avoid_reserve) hugepage_subpool_put_pages(spool, 1); -- 2.25.0.225.g125e21ebc7-goog

An earlier patch in this series disabled file_region coalescing in order to hang the hugetlb_cgroup uncharge info on the file_region entries.

This patch re-adds support for coalescing of file_region entries. Essentially everytime we add an entry, we call a recursive function that tries to coalesce the added region with the regions next to it. The worst case call depth for this function is 3: one to coalesce with the region next to it, one to coalesce to the region prev, and one to reach the base case.

This is an important performance optimization as private mappings add their entries page by page, and we could incur big performance costs for large mappings with lots of file_region entries in their resv_map.

Signed-off-by: Mina Almasry almasrymina@google.com

---

Changes in v12: - Changed logic for coalescing. Instead of checking inline to coalesce with only the region on next or prev, we now have a recursive function that takes care of coalescing in both directions. - For testing this code I added a bunch of debug code that checks that the entries in the resv_map are coalesced appropriately. This passes with libhugetlbfs tests.

--- mm/hugetlb.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 2d62dd35399db..45219cb58ac71 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -276,6 +276,86 @@ static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg, #endif }

+static bool has_same_uncharge_info(struct file_region *rg, + struct file_region *org) +{ +#ifdef CONFIG_CGROUP_HUGETLB + return rg && org && + rg->reservation_counter == org->reservation_counter && + rg->css == org->css; + +#else + return true; +#endif +} + +#ifdef CONFIG_DEBUG_VM +static void dump_resv_map(struct resv_map *resv) +{ + struct list_head *head = &resv->regions; + struct file_region *rg = NULL; + + pr_err("--------- start print resv_map ---------\n"); + list_for_each_entry(rg, head, link) { + pr_err("rg->from=%ld, rg->to=%ld, rg->reservation_counter=%px, rg->css=%px\n", + rg->from, rg->to, rg->reservation_counter, rg->css); + } + pr_err("--------- end print resv_map ---------\n"); +} + +/* Debug function to loop over the resv_map and make sure that coalescing is + * working. + */ +static void check_coalesce_bug(struct resv_map *resv) +{ + struct list_head *head = &resv->regions; + struct file_region *rg = NULL, *nrg = NULL; + + list_for_each_entry(rg, head, link) { + nrg = list_next_entry(rg, link); + + if (&nrg->link == head) + break; + + if (nrg->reservation_counter && nrg->from == rg->to && + nrg->reservation_counter == rg->reservation_counter && + nrg->css == rg->css) { + dump_resv_map(resv); + VM_BUG_ON(true); + } + } +} +#endif + +static void coalesce_file_region(struct resv_map *resv, struct file_region *rg) +{ + struct file_region *nrg = NULL, *prg = NULL; + + prg = list_prev_entry(rg, link); + if (&prg->link != &resv->regions && prg->to == rg->from && + has_same_uncharge_info(prg, rg)) { + prg->to = rg->to; + + list_del(&rg->link); + kfree(rg); + + coalesce_file_region(resv, prg); + return; + } + + nrg = list_next_entry(rg, link); + if (&nrg->link != &resv->regions && nrg->from == rg->to && + has_same_uncharge_info(nrg, rg)) { + nrg->from = rg->from; + + list_del(&rg->link); + kfree(rg); + + coalesce_file_region(resv, nrg); + return; + } +} + /* Must be called with resv->lock held. Calling this with count_only == true * will count the number of pages to be added but will not modify the linked * list. If regions_needed != NULL and count_only == true, then regions_needed @@ -327,6 +407,7 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t, record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg); list_add(&nrg->link, rg->link.prev); + coalesce_file_region(resv, nrg); } else if (regions_needed) *regions_needed += 1; } @@ -344,11 +425,15 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t, resv, last_accounted_offset, t); record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg); list_add(&nrg->link, rg->link.prev); + coalesce_file_region(resv, nrg); } else if (regions_needed) *regions_needed += 1; }

VM_BUG_ON(add < 0); +#ifdef CONFIG_DEBUG_VM + check_coalesce_bug(resv); +#endif return add; }

-- 2.25.0.225.g125e21ebc7-goog

The tests use both shared and private mapped hugetlb memory, and monitors the hugetlb usage counter as well as the hugetlb reservation counter. They test different configurations such as hugetlb memory usage via hugetlbfs, or MAP_HUGETLB, or shmget/shmat, and with and without MAP_POPULATE.

Also add test for hugetlb reservation reparenting, since this is a subtle issue.

Signed-off-by: Mina Almasry almasrymina@google.com Cc: sandipan@linux.ibm.com

---

Changes in v12: - Fixed tests on machines with non-2MB default hugepage size. Changes in v11: - Modify test to not assume 2MB hugepage size. - Updated resv.* to rsvd.* Changes in v10: - Updated tests to resv.* name changes. Changes in v9: - Added tests for hugetlb reparenting. - Make tests explicitly support cgroup v1 and v2 via script argument. Changes in v6: - Updates tests for cgroups-v2 and NORESERVE allocations.

--- tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 1 + .../selftests/vm/charge_reserved_hugetlb.sh | 575 ++++++++++++++++++ .../selftests/vm/hugetlb_reparenting_test.sh | 244 ++++++++ .../selftests/vm/write_hugetlb_memory.sh | 23 + .../testing/selftests/vm/write_to_hugetlbfs.c | 242 ++++++++ 6 files changed, 1086 insertions(+) create mode 100755 tools/testing/selftests/vm/charge_reserved_hugetlb.sh create mode 100755 tools/testing/selftests/vm/hugetlb_reparenting_test.sh create mode 100644 tools/testing/selftests/vm/write_hugetlb_memory.sh create mode 100644 tools/testing/selftests/vm/write_to_hugetlbfs.c

diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore index 31b3c98b6d34d..d3bed9407773c 100644 --- a/tools/testing/selftests/vm/.gitignore +++ b/tools/testing/selftests/vm/.gitignore @@ -14,3 +14,4 @@ virtual_address_range gup_benchmark va_128TBswitch map_fixed_noreplace +write_to_hugetlbfs diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index 7f9a8a8c31da9..662bb95e84c5d 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -22,6 +22,7 @@ TEST_GEN_FILES += userfaultfd ifneq (,$(filter $(ARCH),arm64 ia64 mips64 parisc64 ppc64 riscv64 s390x sh64 sparc64 x86_64)) TEST_GEN_FILES += va_128TBswitch TEST_GEN_FILES += virtual_address_range +TEST_GEN_FILES += write_to_hugetlbfs endif

TEST_PROGS := run_vmtests diff --git a/tools/testing/selftests/vm/charge_reserved_hugetlb.sh b/tools/testing/selftests/vm/charge_reserved_hugetlb.sh new file mode 100755 index 0000000000000..18d33684faade --- /dev/null +++ b/tools/testing/selftests/vm/charge_reserved_hugetlb.sh @@ -0,0 +1,575 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +set -e + +if [[ $(id -u) -ne 0 ]]; then + echo "This test must be run as root. Skipping..." + exit 0 +fi + +fault_limit_file=limit_in_bytes +reservation_limit_file=rsvd.limit_in_bytes +fault_usage_file=usage_in_bytes +reservation_usage_file=rsvd.usage_in_bytes + +if [[ "$1" == "-cgroup-v2" ]]; then + cgroup2=1 + fault_limit_file=max + reservation_limit_file=rsvd.max + fault_usage_file=current + reservation_usage_file=rsvd.current +fi + +cgroup_path=/dev/cgroup/memory +if [[ ! -e $cgroup_path ]]; then + mkdir -p $cgroup_path + if [[ $cgroup2 ]]; then + mount -t cgroup2 none $cgroup_path + else + mount -t cgroup memory,hugetlb $cgroup_path + fi +fi + +if [[ $cgroup2 ]]; then + echo "+hugetlb" >/dev/cgroup/memory/cgroup.subtree_control +fi + +function cleanup() { + if [[ $cgroup2 ]]; then + echo $$ >$cgroup_path/cgroup.procs + else + echo $$ >$cgroup_path/tasks + fi + + if [[ -e /mnt/huge ]]; then + rm -rf /mnt/huge/* + umount /mnt/huge || echo error + rmdir /mnt/huge + fi + if [[ -e $cgroup_path/hugetlb_cgroup_test ]]; then + rmdir $cgroup_path/hugetlb_cgroup_test + fi + if [[ -e $cgroup_path/hugetlb_cgroup_test1 ]]; then + rmdir $cgroup_path/hugetlb_cgroup_test1 + fi + if [[ -e $cgroup_path/hugetlb_cgroup_test2 ]]; then + rmdir $cgroup_path/hugetlb_cgroup_test2 + fi + echo 0 >/proc/sys/vm/nr_hugepages + echo CLEANUP DONE +} + +function expect_equal() { + local expected="$1" + local actual="$2" + local error="$3" + + if [[ "$expected" != "$actual" ]]; then + echo "expected ($expected) != actual ($actual): $3" + cleanup + exit 1 + fi +} + +function get_machine_hugepage_size() { + hpz=$(grep -i hugepagesize /proc/meminfo) + kb=${hpz:14:-3} + mb=$(($kb / 1024)) + echo $mb +} + +MB=$(get_machine_hugepage_size) + +function setup_cgroup() { + local name="$1" + local cgroup_limit="$2" + local reservation_limit="$3" + + mkdir $cgroup_path/$name + + echo writing cgroup limit: "$cgroup_limit" + echo "$cgroup_limit" >$cgroup_path/$name/hugetlb.${MB}MB.$fault_limit_file + + echo writing reseravation limit: "$reservation_limit" + echo "$reservation_limit" > \ + $cgroup_path/$name/hugetlb.${MB}MB.$reservation_limit_file + + if [ -e "$cgroup_path/$name/cpuset.cpus" ]; then + echo 0 >$cgroup_path/$name/cpuset.cpus + fi + if [ -e "$cgroup_path/$name/cpuset.mems" ]; then + echo 0 >$cgroup_path/$name/cpuset.mems + fi +} + +function wait_for_hugetlb_memory_to_get_depleted() { + local cgroup="$1" + local path="/dev/cgroup/memory/$cgroup/hugetlb.${MB}MB.$reservation_usage_file" + # Wait for hugetlbfs memory to get depleted. + while [ $(cat $path) != 0 ]; do + echo Waiting for hugetlb memory to get depleted. + cat $path + sleep 0.5 + done +} + +function wait_for_hugetlb_memory_to_get_reserved() { + local cgroup="$1" + local size="$2" + + local path="/dev/cgroup/memory/$cgroup/hugetlb.${MB}MB.$reservation_usage_file" + # Wait for hugetlbfs memory to get written. + while [ $(cat $path) != $size ]; do + echo Waiting for hugetlb memory reservation to reach size $size. + cat $path + sleep 0.5 + done +} + +function wait_for_hugetlb_memory_to_get_written() { + local cgroup="$1" + local size="$2" + + local path="/dev/cgroup/memory/$cgroup/hugetlb.${MB}MB.$fault_usage_file" + # Wait for hugetlbfs memory to get written. + while [ $(cat $path) != $size ]; do + echo Waiting for hugetlb memory to reach size $size. + cat $path + sleep 0.5 + done +} + +function write_hugetlbfs_and_get_usage() { + local cgroup="$1" + local size="$2" + local populate="$3" + local write="$4" + local path="$5" + local method="$6" + local private="$7" + local expect_failure="$8" + local reserve="$9" + + # Function return values. + reservation_failed=0 + oom_killed=0 + hugetlb_difference=0 + reserved_difference=0 + + local hugetlb_usage=$cgroup_path/$cgroup/hugetlb.${MB}MB.$fault_usage_file + local reserved_usage=$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_file + + local hugetlb_before=$(cat $hugetlb_usage) + local reserved_before=$(cat $reserved_usage) + + echo + echo Starting: + echo hugetlb_usage="$hugetlb_before" + echo reserved_usage="$reserved_before" + echo expect_failure is "$expect_failure" + + output=$(mktemp) + set +e + if [[ "$method" == "1" ]] || [[ "$method" == 2 ]] || + [[ "$private" == "-r" ]] && [[ "$expect_failure" != 1 ]]; then + + bash write_hugetlb_memory.sh "$size" "$populate" "$write" \ + "$cgroup" "$path" "$method" "$private" "-l" "$reserve" 2>&1 | tee $output & + + local write_result=$? + local write_pid=$! + + until grep -q -i "DONE" $output; do + echo waiting for DONE signal. + if ! ps $write_pid > /dev/null + then + echo "FAIL: The write died" + cleanup + exit 1 + fi + sleep 0.5 + done + + echo ================= write_hugetlb_memory.sh output is: + cat $output + echo ================= end output. + + if [[ "$populate" == "-o" ]] || [[ "$write" == "-w" ]]; then + wait_for_hugetlb_memory_to_get_written "$cgroup" "$size" + elif [[ "$reserve" != "-n" ]]; then + wait_for_hugetlb_memory_to_get_reserved "$cgroup" "$size" + else + # This case doesn't produce visible effects, but we still have + # to wait for the async process to start and execute... + sleep 0.5 + fi + + echo write_result is $write_result + else + bash write_hugetlb_memory.sh "$size" "$populate" "$write" \ + "$cgroup" "$path" "$method" "$private" "$reserve" + local write_result=$? + + if [[ "$reserve" != "-n" ]]; then + wait_for_hugetlb_memory_to_get_reserved "$cgroup" "$size" + fi + fi + set -e + + if [[ "$write_result" == 1 ]]; then + reservation_failed=1 + fi + + # On linus/master, the above process gets SIGBUS'd on oomkill, with + # return code 135. On earlier kernels, it gets actual oomkill, with return + # code 137, so just check for both conditions in case we're testing + # against an earlier kernel. + if [[ "$write_result" == 135 ]] || [[ "$write_result" == 137 ]]; then + oom_killed=1 + fi + + local hugetlb_after=$(cat $hugetlb_usage) + local reserved_after=$(cat $reserved_usage) + + echo After write: + echo hugetlb_usage="$hugetlb_after" + echo reserved_usage="$reserved_after" + + hugetlb_difference=$(($hugetlb_after - $hugetlb_before)) + reserved_difference=$(($reserved_after - $reserved_before)) +} + +function cleanup_hugetlb_memory() { + set +e + local cgroup="$1" + if [[ "$(pgrep -f write_to_hugetlbfs)" != "" ]]; then + echo killing write_to_hugetlbfs + killall -2 write_to_hugetlbfs + wait_for_hugetlb_memory_to_get_depleted $cgroup + fi + set -e + + if [[ -e /mnt/huge ]]; then + rm -rf /mnt/huge/* + umount /mnt/huge + rmdir /mnt/huge + fi +} + +function run_test() { + local size=$(($1 * ${MB} * 1024 * 1024)) + local populate="$2" + local write="$3" + local cgroup_limit=$(($4 * ${MB} * 1024 * 1024)) + local reservation_limit=$(($5 * ${MB} * 1024 * 1024)) + local nr_hugepages="$6" + local method="$7" + local private="$8" + local expect_failure="$9" + local reserve="${10}" + + # Function return values. + hugetlb_difference=0 + reserved_difference=0 + reservation_failed=0 + oom_killed=0 + + echo nr hugepages = "$nr_hugepages" + echo "$nr_hugepages" >/proc/sys/vm/nr_hugepages + + setup_cgroup "hugetlb_cgroup_test" "$cgroup_limit" "$reservation_limit" + + mkdir -p /mnt/huge + mount -t hugetlbfs -o pagesize=${MB}M,size=256M none /mnt/huge + + write_hugetlbfs_and_get_usage "hugetlb_cgroup_test" "$size" "$populate" \ + "$write" "/mnt/huge/test" "$method" "$private" "$expect_failure" \ + "$reserve" + + cleanup_hugetlb_memory "hugetlb_cgroup_test" + + local final_hugetlb=$(cat $cgroup_path/hugetlb_cgroup_test/hugetlb.${MB}MB.$fault_usage_file) + local final_reservation=$(cat $cgroup_path/hugetlb_cgroup_test/hugetlb.${MB}MB.$reservation_usage_file) + + echo $hugetlb_difference + echo $reserved_difference + expect_equal "0" "$final_hugetlb" "final hugetlb is not zero" + expect_equal "0" "$final_reservation" "final reservation is not zero" +} + +function run_multiple_cgroup_test() { + local size1="$1" + local populate1="$2" + local write1="$3" + local cgroup_limit1="$4" + local reservation_limit1="$5" + + local size2="$6" + local populate2="$7" + local write2="$8" + local cgroup_limit2="$9" + local reservation_limit2="${10}" + + local nr_hugepages="${11}" + local method="${12}" + local private="${13}" + local expect_failure="${14}" + local reserve="${15}" + + # Function return values. + hugetlb_difference1=0 + reserved_difference1=0 + reservation_failed1=0 + oom_killed1=0 + + hugetlb_difference2=0 + reserved_difference2=0 + reservation_failed2=0 + oom_killed2=0 + + echo nr hugepages = "$nr_hugepages" + echo "$nr_hugepages" >/proc/sys/vm/nr_hugepages + + setup_cgroup "hugetlb_cgroup_test1" "$cgroup_limit1" "$reservation_limit1" + setup_cgroup "hugetlb_cgroup_test2" "$cgroup_limit2" "$reservation_limit2" + + mkdir -p /mnt/huge + mount -t hugetlbfs -o pagesize=${MB}M,size=256M none /mnt/huge + + write_hugetlbfs_and_get_usage "hugetlb_cgroup_test1" "$size1" \ + "$populate1" "$write1" "/mnt/huge/test1" "$method" "$private" \ + "$expect_failure" "$reserve" + + hugetlb_difference1=$hugetlb_difference + reserved_difference1=$reserved_difference + reservation_failed1=$reservation_failed + oom_killed1=$oom_killed + + local cgroup1_hugetlb_usage=$cgroup_path/hugetlb_cgroup_test1/hugetlb.${MB}MB.$fault_usage_file + local cgroup1_reservation_usage=$cgroup_path/hugetlb_cgroup_test1/hugetlb.${MB}MB.$reservation_usage_file + local cgroup2_hugetlb_usage=$cgroup_path/hugetlb_cgroup_test2/hugetlb.${MB}MB.$fault_usage_file + local cgroup2_reservation_usage=$cgroup_path/hugetlb_cgroup_test2/hugetlb.${MB}MB.$reservation_usage_file + + local usage_before_second_write=$(cat $cgroup1_hugetlb_usage) + local reservation_usage_before_second_write=$(cat $cgroup1_reservation_usage) + + write_hugetlbfs_and_get_usage "hugetlb_cgroup_test2" "$size2" \ + "$populate2" "$write2" "/mnt/huge/test2" "$method" "$private" \ + "$expect_failure" "$reserve" + + hugetlb_difference2=$hugetlb_difference + reserved_difference2=$reserved_difference + reservation_failed2=$reservation_failed + oom_killed2=$oom_killed + + expect_equal "$usage_before_second_write" \ + "$(cat $cgroup1_hugetlb_usage)" "Usage changed." + expect_equal "$reservation_usage_before_second_write" \ + "$(cat $cgroup1_reservation_usage)" "Reservation usage changed." + + cleanup_hugetlb_memory + + local final_hugetlb=$(cat $cgroup1_hugetlb_usage) + local final_reservation=$(cat $cgroup1_reservation_usage) + + expect_equal "0" "$final_hugetlb" \ + "hugetlbt_cgroup_test1 final hugetlb is not zero" + expect_equal "0" "$final_reservation" \ + "hugetlbt_cgroup_test1 final reservation is not zero" + + local final_hugetlb=$(cat $cgroup2_hugetlb_usage) + local final_reservation=$(cat $cgroup2_reservation_usage) + + expect_equal "0" "$final_hugetlb" \ + "hugetlb_cgroup_test2 final hugetlb is not zero" + expect_equal "0" "$final_reservation" \ + "hugetlb_cgroup_test2 final reservation is not zero" +} + +cleanup + +for populate in "" "-o"; do + for method in 0 1 2; do + for private in "" "-r"; do + for reserve in "" "-n"; do + + # Skip mmap(MAP_HUGETLB | MAP_SHARED). Doesn't seem to be supported. + if [[ "$method" == 1 ]] && [[ "$private" == "" ]]; then + continue + fi + + # Skip populated shmem tests. Doesn't seem to be supported. + if [[ "$method" == 2"" ]] && [[ "$populate" == "-o" ]]; then + continue + fi + + if [[ "$method" == 2"" ]] && [[ "$reserve" == "-n" ]]; then + continue + fi + + cleanup + echo + echo + echo + echo Test normal case. + echo private=$private, populate=$populate, method=$method, reserve=$reserve + run_test 5 "$populate" "" 10 10 10 "$method" "$private" "0" "$reserve" + + echo Memory charged to hugtlb=$hugetlb_difference + echo Memory charged to reservation=$reserved_difference + + if [[ "$populate" == "-o" ]]; then + expect_equal "$((5 * $MB * 1024 * 1024))" "$hugetlb_difference" \ + "Reserved memory charged to hugetlb cgroup." + else + expect_equal "0" "$hugetlb_difference" \ + "Reserved memory charged to hugetlb cgroup." + fi + + if [[ "$reserve" != "-n" ]] || [[ "$populate" == "-o" ]]; then + expect_equal "$((5 * $MB * 1024 * 1024))" "$reserved_difference" \ + "Reserved memory not charged to reservation usage." + else + expect_equal "0" "$reserved_difference" \ + "Reserved memory not charged to reservation usage." + fi + + echo 'PASS' + + cleanup + echo + echo + echo + echo Test normal case with write. + echo private=$private, populate=$populate, method=$method, reserve=$reserve + run_test 5 "$populate" '-w' 5 5 10 "$method" "$private" "0" "$reserve" + + echo Memory charged to hugtlb=$hugetlb_difference + echo Memory charged to reservation=$reserved_difference + + expect_equal "$((5 * $MB * 1024 * 1024))" "$hugetlb_difference" \ + "Reserved memory charged to hugetlb cgroup." + + expect_equal "$((5 * $MB * 1024 * 1024))" "$reserved_difference" \ + "Reserved memory not charged to reservation usage." + + echo 'PASS' + + cleanup + continue + echo + echo + echo + echo Test more than reservation case. + echo private=$private, populate=$populate, method=$method, reserve=$reserve + + if [ "$reserve" != "-n" ]; then + run_test "5" "$populate" '' "10" "2" "10" "$method" "$private" "1" \ + "$reserve" + + expect_equal "1" "$reservation_failed" "Reservation succeeded." + fi + + echo 'PASS' + + cleanup + + echo + echo + echo + echo Test more than cgroup limit case. + echo private=$private, populate=$populate, method=$method, reserve=$reserve + + # Not sure if shm memory can be cleaned up when the process gets sigbus'd. + if [[ "$method" != 2 ]]; then + run_test 5 "$populate" "-w" 2 10 10 "$method" "$private" "1" "$reserve" + + expect_equal "1" "$oom_killed" "Not oom killed." + fi + echo 'PASS' + + cleanup + + echo + echo + echo + echo Test normal case, multiple cgroups. + echo private=$private, populate=$populate, method=$method, reserve=$reserve + run_multiple_cgroup_test "3" "$populate" "" "10" "10" "5" \ + "$populate" "" "10" "10" "10" \ + "$method" "$private" "0" "$reserve" + + echo Memory charged to hugtlb1=$hugetlb_difference1 + echo Memory charged to reservation1=$reserved_difference1 + echo Memory charged to hugtlb2=$hugetlb_difference2 + echo Memory charged to reservation2=$reserved_difference2 + + if [[ "$reserve" != "-n" ]] || [[ "$populate" == "-o" ]]; then + expect_equal "3" "$reserved_difference1" \ + "Incorrect reservations charged to cgroup 1." + + expect_equal "5" "$reserved_difference2" \ + "Incorrect reservation charged to cgroup 2." + + else + expect_equal "0" "$reserved_difference1" \ + "Incorrect reservations charged to cgroup 1." + + expect_equal "0" "$reserved_difference2" \ + "Incorrect reservation charged to cgroup 2." + fi + + if [[ "$populate" == "-o" ]]; then + expect_equal "3" "$hugetlb_difference1" \ + "Incorrect hugetlb charged to cgroup 1." + + expect_equal "5" "$hugetlb_difference2" \ + "Incorrect hugetlb charged to cgroup 2." + + else + expect_equal "0" "$hugetlb_difference1" \ + "Incorrect hugetlb charged to cgroup 1." + + expect_equal "0" "$hugetlb_difference2" \ + "Incorrect hugetlb charged to cgroup 2." + fi + echo 'PASS' + + cleanup + echo + echo + echo + echo Test normal case with write, multiple cgroups. + echo private=$private, populate=$populate, method=$method, reserve=$reserve + run_multiple_cgroup_test "3" "$populate" "-w" "10" "10" "5" \ + "$populate" "-w" "10" "10" "10" \ + "$method" "$private" "0" "$reserve" + + echo Memory charged to hugtlb1=$hugetlb_difference1 + echo Memory charged to reservation1=$reserved_difference1 + echo Memory charged to hugtlb2=$hugetlb_difference2 + echo Memory charged to reservation2=$reserved_difference2 + + expect_equal "3" "$hugetlb_difference1" \ + "Incorrect hugetlb charged to cgroup 1." + + expect_equal "3" "$reserved_difference1" \ + "Incorrect reservation charged to cgroup 1." + + expect_equal "5" "$hugetlb_difference2" \ + "Incorrect hugetlb charged to cgroup 2." + + expect_equal "5" "$reserved_difference2" \ + "Incorrected reservation charged to cgroup 2." + echo 'PASS' + + cleanup + + done # reserve + done # private + done # populate +done # method + +umount $cgroup_path +rmdir $cgroup_path diff --git a/tools/testing/selftests/vm/hugetlb_reparenting_test.sh b/tools/testing/selftests/vm/hugetlb_reparenting_test.sh new file mode 100755 index 0000000000000..d11d1febccc3b --- /dev/null +++ b/tools/testing/selftests/vm/hugetlb_reparenting_test.sh @@ -0,0 +1,244 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +set -e + +if [[ $(id -u) -ne 0 ]]; then + echo "This test must be run as root. Skipping..." + exit 0 +fi + +usage_file=usage_in_bytes + +if [[ "$1" == "-cgroup-v2" ]]; then + cgroup2=1 + usage_file=current +fi + +CGROUP_ROOT='/dev/cgroup/memory' +MNT='/mnt/huge/' + +if [[ ! -e $CGROUP_ROOT ]]; then + mkdir -p $CGROUP_ROOT + if [[ $cgroup2 ]]; then + mount -t cgroup2 none $CGROUP_ROOT + sleep 1 + echo "+hugetlb +memory" >$CGROUP_ROOT/cgroup.subtree_control + else + mount -t cgroup memory,hugetlb $CGROUP_ROOT + fi +fi + +function get_machine_hugepage_size() { + hpz=$(grep -i hugepagesize /proc/meminfo) + kb=${hpz:14:-3} + mb=$(($kb / 1024)) + echo $mb +} + +MB=$(get_machine_hugepage_size) + +function cleanup() { + echo cleanup + set +e + rm -rf "$MNT"/* 2>/dev/null + umount "$MNT" 2>/dev/null + rmdir "$MNT" 2>/dev/null + rmdir "$CGROUP_ROOT"/a/b 2>/dev/null + rmdir "$CGROUP_ROOT"/a 2>/dev/null + rmdir "$CGROUP_ROOT"/test1 2>/dev/null + echo 0 >/proc/sys/vm/nr_hugepages + set -e +} + +function assert_state() { + local expected_a="$1" + local expected_a_hugetlb="$2" + local expected_b="" + local expected_b_hugetlb="" + + if [ ! -z ${3:-} ] && [ ! -z ${4:-} ]; then + expected_b="$3" + expected_b_hugetlb="$4" + fi + local tolerance=$((5 * 1024 * 1024)) + + local actual_a + actual_a="$(cat "$CGROUP_ROOT"/a/memory.$usage_file)" + if [[ $actual_a -lt $(($expected_a - $tolerance)) ]] || + [[ $actual_a -gt $(($expected_a + $tolerance)) ]]; then + echo actual a = $((${actual_a%% *} / 1024 / 1024)) MB + echo expected a = $((${expected_a%% *} / 1024 / 1024)) MB + echo fail + + cleanup + exit 1 + fi + + local actual_a_hugetlb + actual_a_hugetlb="$(cat "$CGROUP_ROOT"/a/hugetlb.${MB}MB.$usage_file)" + if [[ $actual_a_hugetlb -lt $(($expected_a_hugetlb - $tolerance)) ]] || + [[ $actual_a_hugetlb -gt $(($expected_a_hugetlb + $tolerance)) ]]; then + echo actual a hugetlb = $((${actual_a_hugetlb%% *} / 1024 / 1024)) MB + echo expected a hugetlb = $((${expected_a_hugetlb%% *} / 1024 / 1024)) MB + echo fail + + cleanup + exit 1 + fi + + if [[ -z "$expected_b" || -z "$expected_b_hugetlb" ]]; then + return + fi + + local actual_b + actual_b="$(cat "$CGROUP_ROOT"/a/b/memory.$usage_file)" + if [[ $actual_b -lt $(($expected_b - $tolerance)) ]] || + [[ $actual_b -gt $(($expected_b + $tolerance)) ]]; then + echo actual b = $((${actual_b%% *} / 1024 / 1024)) MB + echo expected b = $((${expected_b%% *} / 1024 / 1024)) MB + echo fail + + cleanup + exit 1 + fi + + local actual_b_hugetlb + actual_b_hugetlb="$(cat "$CGROUP_ROOT"/a/b/hugetlb.${MB}MB.$usage_file)" + if [[ $actual_b_hugetlb -lt $(($expected_b_hugetlb - $tolerance)) ]] || + [[ $actual_b_hugetlb -gt $(($expected_b_hugetlb + $tolerance)) ]]; then + echo actual b hugetlb = $((${actual_b_hugetlb%% *} / 1024 / 1024)) MB + echo expected b hugetlb = $((${expected_b_hugetlb%% *} / 1024 / 1024)) MB + echo fail + + cleanup + exit 1 + fi +} + +function setup() { + echo 100 >/proc/sys/vm/nr_hugepages + mkdir "$CGROUP_ROOT"/a + sleep 1 + if [[ $cgroup2 ]]; then + echo "+hugetlb +memory" >$CGROUP_ROOT/a/cgroup.subtree_control + else + echo 0 >$CGROUP_ROOT/a/cpuset.mems + echo 0 >$CGROUP_ROOT/a/cpuset.cpus + fi + + mkdir "$CGROUP_ROOT"/a/b + + if [[ ! $cgroup2 ]]; then + echo 0 >$CGROUP_ROOT/a/b/cpuset.mems + echo 0 >$CGROUP_ROOT/a/b/cpuset.cpus + fi + + mkdir -p "$MNT" + mount -t hugetlbfs none "$MNT" +} + +write_hugetlbfs() { + local cgroup="$1" + local path="$2" + local size="$3" + + if [[ $cgroup2 ]]; then + echo $$ >$CGROUP_ROOT/$cgroup/cgroup.procs + else + echo 0 >$CGROUP_ROOT/$cgroup/cpuset.mems + echo 0 >$CGROUP_ROOT/$cgroup/cpuset.cpus + echo $$ >"$CGROUP_ROOT/$cgroup/tasks" + fi + ./write_to_hugetlbfs -p "$path" -s "$size" -m 0 -o + if [[ $cgroup2 ]]; then + echo $$ >$CGROUP_ROOT/cgroup.procs + else + echo $$ >"$CGROUP_ROOT/tasks" + fi + echo +} + +set -e + +size=$((${MB} * 1024 * 1024 * 25)) # 50MB = 25 * 2MB hugepages. + +cleanup + +echo +echo +echo Test charge, rmdir, uncharge +setup +echo mkdir +mkdir $CGROUP_ROOT/test1 + +echo write +write_hugetlbfs test1 "$MNT"/test $size + +echo rmdir +rmdir $CGROUP_ROOT/test1 +mkdir $CGROUP_ROOT/test1 + +echo uncharge +rm -rf /mnt/huge/* + +cleanup + +echo done +echo +echo +if [[ ! $cgroup2 ]]; then + echo "Test parent and child hugetlb usage" + setup + + echo write + write_hugetlbfs a "$MNT"/test $size + + echo Assert memory charged correctly for parent use. + assert_state 0 $size 0 0 + + write_hugetlbfs a/b "$MNT"/test2 $size + + echo Assert memory charged correctly for child use. + assert_state 0 $(($size * 2)) 0 $size + + rmdir "$CGROUP_ROOT"/a/b + sleep 5 + echo Assert memory reparent correctly. + assert_state 0 $(($size * 2)) + + rm -rf "$MNT"/* + umount "$MNT" + echo Assert memory uncharged correctly. + assert_state 0 0 + + cleanup +fi + +echo +echo +echo "Test child only hugetlb usage" +echo setup +setup + +echo write +write_hugetlbfs a/b "$MNT"/test2 $size + +echo Assert memory charged correctly for child only use. +assert_state 0 $(($size)) 0 $size + +rmdir "$CGROUP_ROOT"/a/b +echo Assert memory reparent correctly. +assert_state 0 $size + +rm -rf "$MNT"/* +umount "$MNT" +echo Assert memory uncharged correctly. +assert_state 0 0 + +cleanup + +echo ALL PASS + +umount $CGROUP_ROOT +rm -rf $CGROUP_ROOT diff --git a/tools/testing/selftests/vm/write_hugetlb_memory.sh b/tools/testing/selftests/vm/write_hugetlb_memory.sh new file mode 100644 index 0000000000000..d3d0d108924d4 --- /dev/null +++ b/tools/testing/selftests/vm/write_hugetlb_memory.sh @@ -0,0 +1,23 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +set -e + +size=$1 +populate=$2 +write=$3 +cgroup=$4 +path=$5 +method=$6 +private=$7 +want_sleep=$8 +reserve=$9 + +echo "Putting task in cgroup '$cgroup'" +echo $$ > /dev/cgroup/memory/"$cgroup"/cgroup.procs + +echo "Method is $method" + +set +e +./write_to_hugetlbfs -p "$path" -s "$size" "$write" "$populate" -m "$method" \ + "$private" "$want_sleep" "$reserve" diff --git a/tools/testing/selftests/vm/write_to_hugetlbfs.c b/tools/testing/selftests/vm/write_to_hugetlbfs.c new file mode 100644 index 0000000000000..110bc4e4015d6 --- /dev/null +++ b/tools/testing/selftests/vm/write_to_hugetlbfs.c @@ -0,0 +1,242 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This program reserves and uses hugetlb memory, supporting a bunch of + * scenarios needed by the charged_reserved_hugetlb.sh test. + */ + +#include <err.h> +#include <errno.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/types.h> +#include <sys/shm.h> +#include <sys/stat.h> +#include <sys/mman.h> + +/* Global definitions. */ +enum method { + HUGETLBFS, + MMAP_MAP_HUGETLB, + SHM, + MAX_METHOD +}; + + +/* Global variables. */ +static const char *self; +static char *shmaddr; +static int shmid; + +/* + * Show usage and exit. + */ +static void exit_usage(void) +{ + printf("Usage: %s -p <path to hugetlbfs file> -s <size to map> " + "[-m <0=hugetlbfs | 1=mmap(MAP_HUGETLB)>] [-l] [-r] " + "[-o] [-w] [-n]\n", + self); + exit(EXIT_FAILURE); +} + +void sig_handler(int signo) +{ + printf("Received %d.\n", signo); + if (signo == SIGINT) { + printf("Deleting the memory\n"); + if (shmdt((const void *)shmaddr) != 0) { + perror("Detach failure"); + shmctl(shmid, IPC_RMID, NULL); + exit(4); + } + + shmctl(shmid, IPC_RMID, NULL); + printf("Done deleting the memory\n"); + } + exit(2); +} + +int main(int argc, char **argv) +{ + int fd = 0; + int key = 0; + int *ptr = NULL; + int c = 0; + int size = 0; + char path[256] = ""; + enum method method = MAX_METHOD; + int want_sleep = 0, private = 0; + int populate = 0; + int write = 0; + int reserve = 1; + + unsigned long i; + + if (signal(SIGINT, sig_handler) == SIG_ERR) + err(1, "\ncan't catch SIGINT\n"); + + /* Parse command-line arguments. */ + setvbuf(stdout, NULL, _IONBF, 0); + self = argv[0]; + + while ((c = getopt(argc, argv, "s:p:m:owlrn")) != -1) { + switch (c) { + case 's': + size = atoi(optarg); + break; + case 'p': + strncpy(path, optarg, sizeof(path)); + break; + case 'm': + if (atoi(optarg) >= MAX_METHOD) { + errno = EINVAL; + perror("Invalid -m."); + exit_usage(); + } + method = atoi(optarg); + break; + case 'o': + populate = 1; + break; + case 'w': + write = 1; + break; + case 'l': + want_sleep = 1; + break; + case 'r': + private + = 1; + break; + case 'n': + reserve = 0; + break; + default: + errno = EINVAL; + perror("Invalid arg"); + exit_usage(); + } + } + + if (strncmp(path, "", sizeof(path)) != 0) { + printf("Writing to this path: %s\n", path); + } else { + errno = EINVAL; + perror("path not found"); + exit_usage(); + } + + if (size != 0) { + printf("Writing this size: %d\n", size); + } else { + errno = EINVAL; + perror("size not found"); + exit_usage(); + } + + if (!populate) + printf("Not populating.\n"); + else + printf("Populating.\n"); + + if (!write) + printf("Not writing to memory.\n"); + + if (method == MAX_METHOD) { + errno = EINVAL; + perror("-m Invalid"); + exit_usage(); + } else + printf("Using method=%d\n", method); + + if (!private) + printf("Shared mapping.\n"); + else + printf("Private mapping.\n"); + + if (!reserve) + printf("NO_RESERVE mapping.\n"); + else + printf("RESERVE mapping.\n"); + + switch (method) { + case HUGETLBFS: + printf("Allocating using HUGETLBFS.\n"); + fd = open(path, O_CREAT | O_RDWR, 0777); + if (fd == -1) + err(1, "Failed to open file."); + + ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, + (private ? MAP_PRIVATE : MAP_SHARED) | + (populate ? MAP_POPULATE : 0) | + (reserve ? 0 : MAP_NORESERVE), + fd, 0); + + if (ptr == MAP_FAILED) { + close(fd); + err(1, "Error mapping the file"); + } + break; + case MMAP_MAP_HUGETLB: + printf("Allocating using MAP_HUGETLB.\n"); + ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, + (private ? (MAP_PRIVATE | MAP_ANONYMOUS) : + MAP_SHARED) | + MAP_HUGETLB | (populate ? MAP_POPULATE : 0) | + (reserve ? 0 : MAP_NORESERVE), + -1, 0); + + if (ptr == MAP_FAILED) + err(1, "mmap"); + + printf("Returned address is %p\n", ptr); + break; + case SHM: + printf("Allocating using SHM.\n"); + shmid = shmget(key, size, + SHM_HUGETLB | IPC_CREAT | SHM_R | SHM_W); + if (shmid < 0) { + shmid = shmget(++key, size, + SHM_HUGETLB | IPC_CREAT | SHM_R | SHM_W); + if (shmid < 0) + err(1, "shmget"); + } + printf("shmid: 0x%x, shmget key:%d\n", shmid, key); + + ptr = shmat(shmid, NULL, 0); + if (ptr == (int *)-1) { + perror("Shared memory attach failure"); + shmctl(shmid, IPC_RMID, NULL); + exit(2); + } + printf("shmaddr: %p\n", ptr); + + break; + default: + errno = EINVAL; + err(1, "Invalid method."); + } + + if (write) { + printf("Writing to memory.\n"); + memset(ptr, 1, size); + } + + if (want_sleep) { + /* Signal to caller that we're done. */ + printf("DONE\n"); + + /* Hold memory until external kill signal is delivered. */ + while (1) + sleep(100); + } + + if (method == HUGETLBFS) + close(fd); + + return 0; +} -- 2.25.0.225.g125e21ebc7-goog

Add docs for how to use hugetlb_cgroup reservations, and their behavior.

Signed-off-by: Mina Almasry almasrymina@google.com

---

Changes in v11: - Changed resv.* to rsvd.* Changes in v10: - Clarify reparenting behavior. - Reword benefits of reservation limits. Changes in v6: - Updated docs to reflect the new design based on a new counter that tracks both reservations and faults.

--- .../admin-guide/cgroup-v1/hugetlb.rst | 103 ++++++++++++++++-- 1 file changed, 92 insertions(+), 11 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v1/hugetlb.rst b/Documentation/admin-guide/cgroup-v1/hugetlb.rst index a3902aa253a96..338f2c7d7a1cd 100644 --- a/Documentation/admin-guide/cgroup-v1/hugetlb.rst +++ b/Documentation/admin-guide/cgroup-v1/hugetlb.rst @@ -2,13 +2,6 @@ HugeTLB Controller ==================

-The HugeTLB controller allows to limit the HugeTLB usage per control group and -enforces the controller limit during page fault. Since HugeTLB doesn't -support page reclaim, enforcing the limit at page fault time implies that, -the application will get SIGBUS signal if it tries to access HugeTLB pages -beyond its limit. This requires the application to know beforehand how much -HugeTLB pages it would require for its use. - HugeTLB controller can be created by first mounting the cgroup filesystem.

# mount -t cgroup -o hugetlb none /sys/fs/cgroup @@ -28,10 +21,14 @@ process (bash) into it.

Brief summary of control files::

- hugetlb.<hugepagesize>.limit_in_bytes # set/show limit of "hugepagesize" hugetlb usage - hugetlb.<hugepagesize>.max_usage_in_bytes # show max "hugepagesize" hugetlb usage recorded - hugetlb.<hugepagesize>.usage_in_bytes # show current usage for "hugepagesize" hugetlb - hugetlb.<hugepagesize>.failcnt # show the number of allocation failure due to HugeTLB limit + hugetlb.<hugepagesize>.rsvd.limit_in_bytes # set/show limit of "hugepagesize" hugetlb reservations + hugetlb.<hugepagesize>.rsvd.max_usage_in_bytes # show max "hugepagesize" hugetlb reservations and no-reserve faults + hugetlb.<hugepagesize>.rsvd.usage_in_bytes # show current reservations and no-reserve faults for "hugepagesize" hugetlb + hugetlb.<hugepagesize>.rsvd.failcnt # show the number of allocation failure due to HugeTLB reservation limit + hugetlb.<hugepagesize>.limit_in_bytes # set/show limit of "hugepagesize" hugetlb faults + hugetlb.<hugepagesize>.max_usage_in_bytes # show max "hugepagesize" hugetlb usage recorded + hugetlb.<hugepagesize>.usage_in_bytes # show current usage for "hugepagesize" hugetlb + hugetlb.<hugepagesize>.failcnt # show the number of allocation failure due to HugeTLB usage limit

For a system supporting three hugepage sizes (64k, 32M and 1G), the control files include:: @@ -40,11 +37,95 @@ files include:: hugetlb.1GB.max_usage_in_bytes hugetlb.1GB.usage_in_bytes hugetlb.1GB.failcnt + hugetlb.1GB.rsvd.limit_in_bytes + hugetlb.1GB.rsvd.max_usage_in_bytes + hugetlb.1GB.rsvd.usage_in_bytes + hugetlb.1GB.rsvd.failcnt hugetlb.64KB.limit_in_bytes hugetlb.64KB.max_usage_in_bytes hugetlb.64KB.usage_in_bytes hugetlb.64KB.failcnt + hugetlb.64KB.rsvd.limit_in_bytes + hugetlb.64KB.rsvd.max_usage_in_bytes + hugetlb.64KB.rsvd.usage_in_bytes + hugetlb.64KB.rsvd.failcnt hugetlb.32MB.limit_in_bytes hugetlb.32MB.max_usage_in_bytes hugetlb.32MB.usage_in_bytes hugetlb.32MB.failcnt + hugetlb.32MB.rsvd.limit_in_bytes + hugetlb.32MB.rsvd.max_usage_in_bytes + hugetlb.32MB.rsvd.usage_in_bytes + hugetlb.32MB.rsvd.failcnt + + +1. Page fault accounting + +hugetlb.<hugepagesize>.limit_in_bytes +hugetlb.<hugepagesize>.max_usage_in_bytes +hugetlb.<hugepagesize>.usage_in_bytes +hugetlb.<hugepagesize>.failcnt + +The HugeTLB controller allows users to limit the HugeTLB usage (page fault) per +control group and enforces the limit during page fault. Since HugeTLB +doesn't support page reclaim, enforcing the limit at page fault time implies +that, the application will get SIGBUS signal if it tries to fault in HugeTLB +pages beyond its limit. Therefore the application needs to know exactly how many +HugeTLB pages it uses before hand, and the sysadmin needs to make sure that +there are enough available on the machine for all the users to avoid processes +getting SIGBUS. + + +2. Reservation accounting + +hugetlb.<hugepagesize>.rsvd.limit_in_bytes +hugetlb.<hugepagesize>.rsvd.max_usage_in_bytes +hugetlb.<hugepagesize>.rsvd.usage_in_bytes +hugetlb.<hugepagesize>.rsvd.failcnt + +The HugeTLB controller allows to limit the HugeTLB reservations per control +group and enforces the controller limit at reservation time and at the fault of +HugeTLB memory for which no reservation exists. Since reservation limits are +enforced at reservation time (on mmap or shget), reservation limits never causes +the application to get SIGBUS signal if the memory was reserved before hand. For +MAP_NORESERVE allocations, the reservation limit behaves the same as the fault +limit, enforcing memory usage at fault time and causing the application to +receive a SIGBUS if it's crossing its limit. + +Reservation limits are superior to page fault limits described above, since +reservation limits are enforced at reservation time (on mmap or shget), and +never causes the application to get SIGBUS signal if the memory was reserved +before hand. This allows for easier fallback to alternatives such as +non-HugeTLB memory for example. In the case of page fault accounting, it's very +hard to avoid processes getting SIGBUS since the sysadmin needs precisely know +the HugeTLB usage of all the tasks in the system and make sure there is enough +pages to satisfy all requests. Avoiding tasks getting SIGBUS on overcommited +systems is practically impossible with page fault accounting. + + +3. Caveats with shared memory + +For shared HugeTLB memory, both HugeTLB reservation and page faults are charged +to the first task that causes the memory to be reserved or faulted, and all +subsequent uses of this reserved or faulted memory is done without charging. + +Shared HugeTLB memory is only uncharged when it is unreserved or deallocated. +This is usually when the HugeTLB file is deleted, and not when the task that +caused the reservation or fault has exited. + + +4. Caveats with HugeTLB cgroup offline. + +When a HugeTLB cgroup goes offline with some reservations or faults still +charged to it, the behavior is as follows: + +- The fault charges are charged to the parent HugeTLB cgroup (reparented), +- the reservation charges remain on the offline HugeTLB cgroup. + +This means that if a HugeTLB cgroup gets offlined while there is still HugeTLB +reservations charged to it, that cgroup persists as a zombie until all HugeTLB +reservations are uncharged. HugeTLB reservations behave in this manner to match +the memory controller whose cgroups also persist as zombie until all charged +memory is uncharged. Also, the tracking of HugeTLB reservations is a bit more +complex compared to the tracking of HugeTLB faults, so it is significantly +harder to reparent reservations at offline time. -- 2.25.0.225.g125e21ebc7-goog