We should not pin pages in ZONE_MOVABLE. Currently, we do not pin only movable CMA pages. Generalize the function that migrates CMA pages to migrate all movable pages. Use is_pinnable_page() to check which pages need to be migrated
Signed-off-by: Pavel Tatashin pasha.tatashin@soleen.com Reviewed-by: John Hubbard jhubbard@nvidia.com --- include/linux/migrate.h | 1 + include/linux/mmzone.h | 11 ++++-- include/trace/events/migrate.h | 3 +- mm/gup.c | 68 ++++++++++++++-------------------- 4 files changed, 39 insertions(+), 44 deletions(-)
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 4594838a0f7c..aae5ef0b3ba1 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -27,6 +27,7 @@ enum migrate_reason { MR_MEMPOLICY_MBIND, MR_NUMA_MISPLACED, MR_CONTIG_RANGE, + MR_LONGTERM_PIN, MR_TYPES };
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index b593316bff3d..25c0c13ba4b1 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -386,9 +386,14 @@ enum zone_type { * likely to succeed, and to locally limit unmovable allocations - e.g., * to increase the number of THP/huge pages. Notable special cases are: * - * 1. Pinned pages: (long-term) pinning of movable pages might - * essentially turn such pages unmovable. Memory offlining might - * retry a long time. + * 1. Pinned pages: (long-term) pinning of movable pages is avoided + * when pages are pinned and faulted, but it is still possible that + * address space already has pages in ZONE_MOVABLE at the time when + * pages are pinned (i.e. user has touches that memory before + * pinning). In such case we try to migrate them to a different zone, + * but if migration fails the pages can still end-up pinned in + * ZONE_MOVABLE. In such case, memory offlining might retry a long + * time and will only succeed once user application unpins pages. * 2. memblock allocations: kernelcore/movablecore setups might create * situations where ZONE_MOVABLE contains unmovable allocations * after boot. Memory offlining and allocations fail early. diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h index 4d434398d64d..363b54ce104c 100644 --- a/include/trace/events/migrate.h +++ b/include/trace/events/migrate.h @@ -20,7 +20,8 @@ EM( MR_SYSCALL, "syscall_or_cpuset") \ EM( MR_MEMPOLICY_MBIND, "mempolicy_mbind") \ EM( MR_NUMA_MISPLACED, "numa_misplaced") \ - EMe(MR_CONTIG_RANGE, "contig_range") + EM( MR_CONTIG_RANGE, "contig_range") \ + EMe(MR_LONGTERM_PIN, "longterm_pin")
/* * First define the enums in the above macros to be exported to userspace diff --git a/mm/gup.c b/mm/gup.c index 04602e94856b..591d8e2dfc70 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -89,11 +89,12 @@ static __maybe_unused struct page *try_grab_compound_head(struct page *page, int orig_refs = refs;
/* - * Can't do FOLL_LONGTERM + FOLL_PIN with CMA in the gup fast - * path, so fail and let the caller fall back to the slow path. + * Can't do FOLL_LONGTERM + FOLL_PIN gup fast path if not in a + * right zone, so fail and let the caller fall back to the slow + * path. */ - if (unlikely(flags & FOLL_LONGTERM) && - is_migrate_cma_page(page)) + if (unlikely((flags & FOLL_LONGTERM) && + !is_pinnable_page(page))) return NULL;
/* @@ -1549,19 +1550,18 @@ struct page *get_dump_page(unsigned long addr) } #endif /* CONFIG_ELF_CORE */
-#ifdef CONFIG_CMA -static long check_and_migrate_cma_pages(struct mm_struct *mm, - unsigned long start, - unsigned long nr_pages, - struct page **pages, - struct vm_area_struct **vmas, - unsigned int gup_flags) +static long check_and_migrate_movable_pages(struct mm_struct *mm, + unsigned long start, + unsigned long nr_pages, + struct page **pages, + struct vm_area_struct **vmas, + unsigned int gup_flags) { unsigned long i; unsigned long step; bool drain_allow = true; bool migrate_allow = true; - LIST_HEAD(cma_page_list); + LIST_HEAD(movable_page_list); long ret = nr_pages; struct migration_target_control mtc = { .nid = NUMA_NO_NODE, @@ -1579,13 +1579,12 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, */ step = compound_nr(head) - (pages[i] - head); /* - * If we get a page from the CMA zone, since we are going to - * be pinning these entries, we might as well move them out - * of the CMA zone if possible. + * If we get a movable page, since we are going to be pinning + * these entries, try to move them out if possible. */ - if (is_migrate_cma_page(head)) { + if (!is_pinnable_page(head)) { if (PageHuge(head)) - isolate_huge_page(head, &cma_page_list); + isolate_huge_page(head, &movable_page_list); else { if (!PageLRU(head) && drain_allow) { lru_add_drain_all(); @@ -1593,7 +1592,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, }
if (!isolate_lru_page(head)) { - list_add_tail(&head->lru, &cma_page_list); + list_add_tail(&head->lru, &movable_page_list); mod_node_page_state(page_pgdat(head), NR_ISOLATED_ANON + page_is_file_lru(head), @@ -1605,7 +1604,7 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, i += step; }
- if (!list_empty(&cma_page_list)) { + if (!list_empty(&movable_page_list)) { /* * drop the above get_user_pages reference. */ @@ -1615,25 +1614,24 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, for (i = 0; i < nr_pages; i++) put_page(pages[i]);
- if (migrate_pages(&cma_page_list, alloc_migration_target, NULL, - (unsigned long)&mtc, MIGRATE_SYNC, MR_CONTIG_RANGE)) { + if (migrate_pages(&movable_page_list, alloc_migration_target, NULL, + (unsigned long)&mtc, MIGRATE_SYNC, MR_LONGTERM_PIN)) { /* * some of the pages failed migration. Do get_user_pages * without migration. */ migrate_allow = false;
- if (!list_empty(&cma_page_list)) - putback_movable_pages(&cma_page_list); + if (!list_empty(&movable_page_list)) + putback_movable_pages(&movable_page_list); } /* * We did migrate all the pages, Try to get the page references - * again migrating any new CMA pages which we failed to isolate - * earlier. + * again migrating any pages which we failed to isolate earlier. */ ret = __get_user_pages_locked(mm, start, nr_pages, - pages, vmas, NULL, - gup_flags); + pages, vmas, NULL, + gup_flags);
if ((ret > 0) && migrate_allow) { nr_pages = ret; @@ -1644,17 +1642,6 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm,
return ret; } -#else -static long check_and_migrate_cma_pages(struct mm_struct *mm, - unsigned long start, - unsigned long nr_pages, - struct page **pages, - struct vm_area_struct **vmas, - unsigned int gup_flags) -{ - return nr_pages; -} -#endif /* CONFIG_CMA */
/* * __gup_longterm_locked() is a wrapper for __get_user_pages_locked which @@ -1678,8 +1665,9 @@ static long __gup_longterm_locked(struct mm_struct *mm,
if (gup_flags & FOLL_LONGTERM) { if (rc > 0) - rc = check_and_migrate_cma_pages(mm, start, rc, pages, - vmas, gup_flags); + rc = check_and_migrate_movable_pages(mm, start, rc, + pages, vmas, + gup_flags); memalloc_pin_restore(flags); } return rc;