The patch titled
memrlimit: improve fork and error handling
has been added to the -mm tree. Its filename is
memrlimit-add-memrlimit-controller-accounting-and-control-memrlimit-improve-fork-and-error-handling.patch
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See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memrlimit: improve fork and error handling
From: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
The fork path of the memrlimit patches adds an additional down_write() of
mmap_sem. Ideally memrlimit should be zero overhead for non users and the
error handling path also needed improvement. This patch fixes both problems.
The accounting has now been moved from copy_mm() to dup_mmap()
Reviewed-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: Sudhir Kumar <skumar@xxxxxxxxxxxxxxxxxx>
Cc: YAMAMOTO Takashi <yamamoto@xxxxxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Pavel Emelianov <xemul@xxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/fork.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff -puN kernel/fork.c~memrlimit-add-memrlimit-controller-accounting-and-control-memrlimit-improve-fork-and-error-handling kernel/fork.c
--- a/kernel/fork.c~memrlimit-add-memrlimit-controller-accounting-and-control-memrlimit-improve-fork-and-error-handling
+++ a/kernel/fork.c
@@ -261,7 +261,7 @@ static int dup_mmap(struct mm_struct *mm
struct vm_area_struct *mpnt, *tmp, **pprev;
struct rb_node **rb_link, *rb_parent;
int retval;
- unsigned long charge;
+ unsigned long charge, uncharged = 0;
struct mempolicy *pol;
down_write(&oldmm->mmap_sem);
@@ -271,6 +271,15 @@ static int dup_mmap(struct mm_struct *mm
*/
down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);
+ /*
+ * Uncharging as a result of failure is done by mmput()
+ * in dup_mm()
+ */
+ if (memrlimit_cgroup_charge_as(oldmm, oldmm->total_vm)) {
+ retval = -ENOMEM;
+ goto out;
+ }
+
mm->locked_vm = 0;
mm->mmap = NULL;
mm->mmap_cache = NULL;
@@ -292,6 +301,7 @@ static int dup_mmap(struct mm_struct *mm
vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file,
-pages);
memrlimit_cgroup_uncharge_as(mm, pages);
+ uncharged += pages;
continue;
}
charge = 0;
@@ -629,12 +639,6 @@ static int copy_mm(unsigned long clone_f
atomic_inc(&oldmm->mm_users);
mm = oldmm;
goto good_mm;
- } else {
- down_write(&oldmm->mmap_sem);
- retval = memrlimit_cgroup_charge_as(oldmm, oldmm->total_vm);
- up_write(&oldmm->mmap_sem);
- if (retval)
- goto fail_nomem;
}
retval = -ENOMEM;
_
Patches currently in -mm which might be from balbir@xxxxxxxxxxxxxxxxxx are
delay-accounting-maintainer-update.patch
cgroup-use-read-lock-to-guard-find_existing_css_set.patch
mark-res_counter_charge_locked-with-__must_check.patch
memcg-make-global-var-read_mostly.patch
memcg-avoid-unnecessary-initialization.patch
memcg-remove-refcnt-from-page_cgroup-fix-memcg-fix-mem_cgroup_end_migration-race.patch
memcg-clean-up-checking-of-the-disabled-flag.patch
memrlimit-add-memrlimit-controller-documentation.patch
memrlimit-setup-the-memrlimit-controller.patch
memrlimit-cgroup-mm-owner-callback-changes-to-add-task-info.patch
memrlimit-cgroup-mm-owner-callback-changes-to-add-task-info-memrlimit-fix-sleep-inside-sleeplock-in-mm_update_next_owner.patch
memrlimit-add-memrlimit-controller-accounting-and-control.patch
memrlimit-add-memrlimit-controller-accounting-and-control-fix.patch
memrlimit-add-memrlimit-controller-accounting-and-control-memrlimit-improve-fork-and-error-handling.patch
memrlimit-improve-error-handling.patch
memrlimit-improve-error-handling-update.patch
memrlimit-handle-attach_task-failure-add-can_attach-callback.patch
memrlimit-handle-attach_task-failure-add-can_attach-callback-update.patch
distinct-tgid-tid-i-o-statistics.patch
per-task-delay-accounting-add-memory-reclaim-delay.patch
per-task-delay-accounting-update-document-and-getdelaysc-for-memory-reclaim.patch
gcov-architecture-specific-compile-flag-adjustments-x86_64-fix.patch
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