The patch titled
Subject: mm, proc: make clear_refs killable
has been removed from the -mm tree. Its filename was
mm-proc-make-clear_refs-killable.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm, proc: make clear_refs killable
CLEAR_REFS_MM_HIWATER_RSS and CLEAR_REFS_SOFT_DIRTY are relying on
mmap_sem for write. If the waiting task gets killed by the oom killer and
it would operate on the current's mm it would block oom_reaper from
asynchronous address space reclaim and reduce the chances of timely OOM
resolving. Wait for the lock in the killable mode and return with EINTR
if the task got killed while waiting. This will also expedite the return
to the userspace and do_exit even if the mm is remote.
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Petr Cermak <petrcermak@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff -puN fs/proc/task_mmu.c~mm-proc-make-clear_refs-killable fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~mm-proc-make-clear_refs-killable
+++ a/fs/proc/task_mmu.c
@@ -1027,11 +1027,15 @@ static ssize_t clear_refs_write(struct f
};
if (type == CLEAR_REFS_MM_HIWATER_RSS) {
+ if (down_write_killable(&mm->mmap_sem)) {
+ count = -EINTR;
+ goto out_mm;
+ }
+
/*
* Writing 5 to /proc/pid/clear_refs resets the peak
* resident set size to this mm's current rss value.
*/
- down_write(&mm->mmap_sem);
reset_mm_hiwater_rss(mm);
up_write(&mm->mmap_sem);
goto out_mm;
@@ -1043,7 +1047,10 @@ static ssize_t clear_refs_write(struct f
if (!(vma->vm_flags & VM_SOFTDIRTY))
continue;
up_read(&mm->mmap_sem);
- down_write(&mm->mmap_sem);
+ if (down_write_killable(&mm->mmap_sem)) {
+ count = -EINTR;
+ goto out_mm;
+ }
for (vma = mm->mmap; vma; vma = vma->vm_next) {
vma->vm_flags &= ~VM_SOFTDIRTY;
vma_set_page_prot(vma);
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
oom_reaper-close-race-with-exiting-task.patch
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