The commit is pushed to "branch-rh7-3.10.0-514.vz7.27.x-ovz" and will appear at
https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.vz7.27.10
------>
commit aa466d093712b6859118b15830f150a5c7ec74b4
Author: Johannes Weiner <han...@cmpxchg.org>
Date: Mon Jan 16 20:27:11 2017 +0400
ms/mm: memcontrol: simplify move precharge function
The move precharge function does some baroque things: it tries raw
res_counter charging of the entire amount first, and then falls back to
a loop of one-by-one charges, with checks for pending signals and
cond_resched() batching.
Just use mem_cgroup_try_charge() without __GFP_WAIT for the first bulk
charge attempt. In the one-by-one loop, remove the signal check (this
is already checked in try_charge), and simply call cond_resched() after
every charge - it's not that expensive.
Signed-off-by: Johannes Weiner <han...@cmpxchg.org>
Acked-by: Michal Hocko <mho...@suse.cz>
Cc: Hugh Dickins <hu...@google.com>
Cc: Tejun Heo <t...@kernel.org>
Cc: Vladimir Davydov <vdavy...@parallels.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
https://jira.sw.ru/browse/PSBM-51558
(cherry picked from commit 9476db974d9e18885123fcebc09f4596bb922e5f)
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
mm/memcontrol.c | 48 +++++++++++++++---------------------------------
1 file changed, 15 insertions(+), 33 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a1aab9f..32533bf 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6722,56 +6722,38 @@ static void mem_cgroup_css_free(struct cgroup *cont)
#ifdef CONFIG_MMU
/* Handlers for move charge at task migration. */
-#define PRECHARGE_COUNT_AT_ONCE 256
static int mem_cgroup_do_precharge(unsigned long count)
{
int ret = 0;
- int batch_count = PRECHARGE_COUNT_AT_ONCE;
- struct mem_cgroup *memcg = mc.to;
- if (mem_cgroup_is_root(memcg)) {
+ if (mem_cgroup_is_root(mc.to)) {
mc.precharge += count;
/* we don't need css_get for root */
return ret;
}
- /* try to charge at once */
- if (count > 1) {
- struct page_counter *dummy;
- /*
- * "memcg" cannot be under rmdir() because we've already checked
- * by cgroup_lock_live_cgroup() that it is not removed and we
- * are still under the same cgroup_mutex. So we can postpone
- * css_get().
- */
- if (page_counter_try_charge(&memcg->memory, count, &dummy))
- goto one_by_one;
- if (do_swap_account &&
- page_counter_try_charge(&memcg->memsw, count, &dummy)) {
- page_counter_uncharge(&memcg->memory, count);
- goto one_by_one;
- }
+
+ /* Try a single bulk charge without reclaim first */
+ ret = mem_cgroup_try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count);
+ if (!ret) {
mc.precharge += count;
return ret;
}
-one_by_one:
- /* fall back to one by one charge */
+
+ /* Try charges one by one with reclaim */
while (count--) {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
- if (!batch_count--) {
- batch_count = PRECHARGE_COUNT_AT_ONCE;
- cond_resched();
- }
- ret = mem_cgroup_try_charge(memcg,
+ ret = mem_cgroup_try_charge(mc.to,
GFP_KERNEL & ~__GFP_NORETRY, 1);
+ /*
+ * In case of failure, any residual charges against
+ * mc.to will be dropped by mem_cgroup_clear_mc()
+ * later on.
+ */
if (ret)
- /* mem_cgroup_clear_mc() will do uncharge later */
return ret;
mc.precharge++;
+ cond_resched();
}
- return ret;
+ return 0;
}
/**
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