The patch titled Subject: mm: khugepaged: recalculate min_free_kbytes after memory hotplug as expected by khugepaged has been added to the -mm tree. Its filename is mm-khugepaged-recalculate-min_free_kbytes-after-memory-hotplug-as-expected-by-khugepaged.patch
This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-khugepaged-recalculate-min_free... and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-khugepaged-recalculate-min_free...
Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated there every 3-4 working days
------------------------------------------------------ From: Vijay Balakrishna vijayb@linux.microsoft.com Subject: mm: khugepaged: recalculate min_free_kbytes after memory hotplug as expected by khugepaged
When memory is hotplug added or removed the min_free_kbytes must be recalculated based on what is expected by khugepaged. Currently after hotplug, min_free_kbytes will be set to a lower default and higher default set when THP enabled is lost. This leaves the system with small min_free_kbytes which isn't suitable for systems especially with network intensive loads. Typical failure symptoms include HW WATCHDOG reset, soft lockup hang notices, NETDEVICE WATCHDOG timeouts, and OOM process kills.
Link: https://lkml.kernel.org/r/1600204258-13683-1-git-send-email-vijayb@linux.mic... Fixes: f000565adb77 ("thp: set recommended min free kbytes") Signed-off-by: Vijay Balakrishna vijayb@linux.microsoft.com Reviewed-by: Pavel Tatashin pasha.tatashin@soleen.com Cc: Allen Pais apais@microsoft.com Cc: Andrea Arcangeli aarcange@redhat.com Cc: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Cc: Michal Hocko mhocko@suse.com Cc: Oleg Nesterov oleg@redhat.com Cc: Song Liu songliubraving@fb.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
include/linux/khugepaged.h | 5 +++++ mm/khugepaged.c | 13 +++++++++++-- mm/memory_hotplug.c | 3 +++ 3 files changed, 19 insertions(+), 2 deletions(-)
--- a/include/linux/khugepaged.h~mm-khugepaged-recalculate-min_free_kbytes-after-memory-hotplug-as-expected-by-khugepaged +++ a/include/linux/khugepaged.h @@ -15,6 +15,7 @@ extern int __khugepaged_enter(struct mm_ extern void __khugepaged_exit(struct mm_struct *mm); extern int khugepaged_enter_vma_merge(struct vm_area_struct *vma, unsigned long vm_flags); +extern void khugepaged_min_free_kbytes_update(void); #ifdef CONFIG_SHMEM extern void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr); #else @@ -85,6 +86,10 @@ static inline void collapse_pte_mapped_t unsigned long addr) { } + +static inline void khugepaged_min_free_kbytes_update(void) +{ +} #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif /* _LINUX_KHUGEPAGED_H */ --- a/mm/khugepaged.c~mm-khugepaged-recalculate-min_free_kbytes-after-memory-hotplug-as-expected-by-khugepaged +++ a/mm/khugepaged.c @@ -56,6 +56,9 @@ enum scan_result { #define CREATE_TRACE_POINTS #include <trace/events/huge_memory.h>
+static struct task_struct *khugepaged_thread __read_mostly; +static DEFINE_MUTEX(khugepaged_mutex); + /* default scan 8*512 pte (or vmas) every 30 second */ static unsigned int khugepaged_pages_to_scan __read_mostly; static unsigned int khugepaged_pages_collapsed; @@ -2292,8 +2295,6 @@ static void set_recommended_min_free_kby
int start_stop_khugepaged(void) { - static struct task_struct *khugepaged_thread __read_mostly; - static DEFINE_MUTEX(khugepaged_mutex); int err = 0;
mutex_lock(&khugepaged_mutex); @@ -2320,3 +2321,11 @@ fail: mutex_unlock(&khugepaged_mutex); return err; } + +void khugepaged_min_free_kbytes_update(void) +{ + mutex_lock(&khugepaged_mutex); + if (khugepaged_enabled() && khugepaged_thread) + set_recommended_min_free_kbytes(); + mutex_unlock(&khugepaged_mutex); +} --- a/mm/memory_hotplug.c~mm-khugepaged-recalculate-min_free_kbytes-after-memory-hotplug-as-expected-by-khugepaged +++ a/mm/memory_hotplug.c @@ -36,6 +36,7 @@ #include <linux/memblock.h> #include <linux/compaction.h> #include <linux/rmap.h> +#include <linux/khugepaged.h>
#include <asm/tlbflush.h>
@@ -857,6 +858,7 @@ int __ref online_pages(unsigned long pfn zone_pcp_update(zone);
init_per_zone_wmark_min(); + khugepaged_min_free_kbytes_update();
kswapd_run(nid); kcompactd_run(nid); @@ -1614,6 +1616,7 @@ static int __ref __offline_pages(unsigne pgdat_resize_unlock(zone->zone_pgdat, &flags);
init_per_zone_wmark_min(); + khugepaged_min_free_kbytes_update();
if (!populated_zone(zone)) { zone_pcp_reset(zone); _
Patches currently in -mm which might be from vijayb@linux.microsoft.com are
mm-khugepaged-recalculate-min_free_kbytes-after-memory-hotplug-as-expected-by-khugepaged.patch mm-khugepaged-avoid-overriding-min_free_kbytes-set-by-user.patch