The patch titled
Subject: mm, oom: remove unnecessary exit_state check
has been added to the -mm tree. Its filename is
mm-oom-remove-unnecessary-exit_state-check.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-oom-remove-unnecessary-exit_state-check.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-oom-remove-unnecessary-exit_state-check.patch
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From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm, oom: remove unnecessary exit_state check
The oom killer scans each process and determines whether it is eligible for oom
kill or whether the oom killer should abort because of concurrent memory
freeing. It will abort when an eligible process is found to have TIF_MEMDIE
set, meaning it has already been oom killed and we're waiting for it to exit.
Processes with task->mm == NULL should not be considered because they are either
kthreads or have already detached their memory and killing them would not lead
to memory freeing. That memory is only freed after exit_mm() has returned,
however, and not when task->mm is first set to NULL.
Clear TIF_MEMDIE after exit_mm()'s mmput() so that an oom killed process is no
longer considered for oom kill, but only until exit_mm() has returned. This was
fragile in the past because it relied on exit_notify() to be reached before no
longer considering TIF_MEMDIE processes.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/exit.c | 1 +
mm/oom_kill.c | 2 --
2 files changed, 1 insertion(+), 2 deletions(-)
diff -puN kernel/exit.c~mm-oom-remove-unnecessary-exit_state-check kernel/exit.c
--- a/kernel/exit.c~mm-oom-remove-unnecessary-exit_state-check
+++ a/kernel/exit.c
@@ -455,6 +455,7 @@ static void exit_mm(struct task_struct *
task_unlock(tsk);
mm_update_next_owner(mm);
mmput(mm);
+ clear_thread_flag(TIF_MEMDIE);
}
/*
diff -puN mm/oom_kill.c~mm-oom-remove-unnecessary-exit_state-check mm/oom_kill.c
--- a/mm/oom_kill.c~mm-oom-remove-unnecessary-exit_state-check
+++ a/mm/oom_kill.c
@@ -256,8 +256,6 @@ enum oom_scan_t oom_scan_process_thread(
unsigned long totalpages, const nodemask_t *nodemask,
bool force_kill)
{
- if (task->exit_state)
- return OOM_SCAN_CONTINUE;
if (oom_unkillable_task(task, NULL, nodemask))
return OOM_SCAN_CONTINUE;
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
mm-thp-do-not-allow-thp-faults-to-avoid-cpuset-restrictions.patch
x86-numa-setup_node_data-drop-dead-code-and-rename-function.patch
x86-numa-setup_node_data-drop-dead-code-and-rename-function-v2.patch
score-ptrace-remove-the-macros-which-not-be-used-currently.patch
mm-slabc-add-__init-to-init_lock_keys.patch
slab-common-add-functions-for-kmem_cache_node-access.patch
slab-common-add-functions-for-kmem_cache_node-access-fix.patch
slub-use-new-node-functions.patch
slub-use-new-node-functions-fix.patch
slab-use-get_node-and-kmem_cache_node-functions.patch
slab-use-get_node-and-kmem_cache_node-functions-fix.patch
slab-use-get_node-and-kmem_cache_node-functions-fix-2.patch
mm-slabh-wrap-the-whole-file-with-guarding-macro.patch
mm-slub-mark-resiliency_test-as-init-text.patch
mm-slub-slub_debug=n-use-the-same-alloc-free-hooks-as-for-slub_debug=y.patch
slab-add-unlikely-macro-to-help-compiler.patch
slab-move-up-code-to-get-kmem_cache_node-in-free_block.patch
slab-defer-slab_destroy-in-free_block.patch
slab-defer-slab_destroy-in-free_block-v4.patch
slab-factor-out-initialization-of-arracy-cache.patch
slab-introduce-alien_cache.patch
slab-use-the-lock-on-alien_cache-instead-of-the-lock-on-array_cache.patch
slab-destroy-a-slab-without-holding-any-alien-cache-lock.patch
slab-remove-a-useless-lockdep-annotation.patch
slab-remove-bad_alien_magic.patch
slab-change-int-to-size_t-for-representing-allocation-size.patch
slub-reduce-duplicate-creation-on-the-first-object.patch
mm-move-slab-related-stuff-from-utilc-to-slab_commonc.patch
mm-trivial-comment-cleanup-in-slabc.patch
mm-slub-fix-some-indenting-in-cmpxchg_double_slab.patch
slab-fix-the-alias-countvia-sysfs-of-slab-cache.patch
mm-readaheadc-remove-unused-file_ra_state-from-count_history_pages.patch
mm-memory_hotplugc-add-__meminit-to-grow_zone_span-grow_pgdat_span.patch
mm-page_allocc-unexport-alloc_pages_exact_nid.patch
mm-page_alloc-simplify-drain_zone_pages-by-using-min.patch
mm-mem-hotplug-replace-simple_strtoull-with-kstrtoull.patch
mm-vmallocc-add-a-schedule-point-to-vmalloc.patch
mm-vmallocc-add-a-schedule-point-to-vmalloc-fix.patch
mm-vmalloc-constify-allocation-mask.patch
mmhugetlb-make-unmap_ref_private-return-void.patch
mmhugetlb-simplify-error-handling-in-hugetlb_cow.patch
mm-hugetlb-generalize-writes-to-nr_hugepages.patch
mm-hugetlb-generalize-writes-to-nr_hugepages-fix.patch
mm-hugetlb-remove-hugetlb_zero-and-hugetlb_infinity.patch
mm-make-copy_pte_range-static-again.patch
mm-thp-only-collapse-hugepages-to-nodes-with-affinity-for-zone_reclaim_mode.patch
mm-writeback-prevent-race-when-calculating-dirty-limits.patch
slub-remove-kmemcg-id-from-create_unique_id.patch
mm-oom-ensure-memoryless-node-zonelist-always-includes-zones.patch
mm-oom-remove-unnecessary-check-for-null-zonelist.patch
mm-oom-rename-zonelist-locking-functions.patch
mm-thp-restructure-thp-avoidance-of-light-synchronous-migration.patch
mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch
mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages-fix.patch
mm-oom-remove-unnecessary-exit_state-check.patch
include-kernelh-rewrite-min3-max3-and-clamp-using-min-and-max.patch
lib-add-size-unit-t-p-e-to-memparse.patch
mm-utilc-add-kstrimdup.patch
fs-proc-kcorec-use-page_align-instead-of-alignpage_size.patch
fork-exec-cleanup-mm-initialization.patch
fork-reset-mm-pinned_vm.patch
fork-copy-mms-vm-usage-counters-under-mmap_sem.patch
linux-next.patch
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