The patch titled
Subject: mm: page_counter: let page_counter_try_charge() return bool
has been added to the -mm tree. Its filename is
mm-page_counter-let-page_counter_try_charge-return-bool.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_counter-let-page_counter_try_charge-return-bool.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_counter-let-page_counter_try_charge-return-bool.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: page_counter: let page_counter_try_charge() return bool
page_counter_try_charge() currently returns 0 on success and -ENOMEM on
failure, which is surprising behavior given the function name.
Make it follow the expected pattern of try_stuff() functions that return a
boolean true to indicate success, or false for failure.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page_counter.h | 6 +++---
mm/hugetlb_cgroup.c | 3 ++-
mm/memcontrol.c | 11 +++++------
mm/page_counter.c | 14 +++++++-------
4 files changed, 17 insertions(+), 17 deletions(-)
diff -puN include/linux/page_counter.h~mm-page_counter-let-page_counter_try_charge-return-bool include/linux/page_counter.h
--- a/include/linux/page_counter.h~mm-page_counter-let-page_counter_try_charge-return-bool
+++ a/include/linux/page_counter.h
@@ -36,9 +36,9 @@ static inline unsigned long page_counter
void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
void page_counter_charge(struct page_counter *counter, unsigned long nr_pages);
-int page_counter_try_charge(struct page_counter *counter,
- unsigned long nr_pages,
- struct page_counter **fail);
+bool page_counter_try_charge(struct page_counter *counter,
+ unsigned long nr_pages,
+ struct page_counter **fail);
void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
int page_counter_limit(struct page_counter *counter, unsigned long limit);
int page_counter_memparse(const char *buf, const char *max,
diff -puN mm/hugetlb_cgroup.c~mm-page_counter-let-page_counter_try_charge-return-bool mm/hugetlb_cgroup.c
--- a/mm/hugetlb_cgroup.c~mm-page_counter-let-page_counter_try_charge-return-bool
+++ a/mm/hugetlb_cgroup.c
@@ -186,7 +186,8 @@ again:
}
rcu_read_unlock();
- ret = page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, &counter);
+ if (!page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, &counter))
+ ret = -ENOMEM;
css_put(&h_cg->css);
done:
*ptr = h_cg;
diff -puN mm/memcontrol.c~mm-page_counter-let-page_counter_try_charge-return-bool mm/memcontrol.c
--- a/mm/memcontrol.c~mm-page_counter-let-page_counter_try_charge-return-bool
+++ a/mm/memcontrol.c
@@ -2016,8 +2016,8 @@ retry:
return 0;
if (!do_swap_account ||
- !page_counter_try_charge(&memcg->memsw, batch, &counter)) {
- if (!page_counter_try_charge(&memcg->memory, batch, &counter))
+ page_counter_try_charge(&memcg->memsw, batch, &counter)) {
+ if (page_counter_try_charge(&memcg->memory, batch, &counter))
goto done_restock;
if (do_swap_account)
page_counter_uncharge(&memcg->memsw, batch);
@@ -2381,14 +2381,13 @@ int __memcg_kmem_charge_memcg(struct pag
{
unsigned int nr_pages = 1 << order;
struct page_counter *counter;
- int ret = 0;
+ int ret;
if (!memcg_kmem_is_active(memcg))
return 0;
- ret = page_counter_try_charge(&memcg->kmem, nr_pages, &counter);
- if (ret)
- return ret;
+ if (!page_counter_try_charge(&memcg->kmem, nr_pages, &counter))
+ return -ENOMEM;
ret = try_charge(memcg, gfp, nr_pages);
if (ret) {
diff -puN mm/page_counter.c~mm-page_counter-let-page_counter_try_charge-return-bool mm/page_counter.c
--- a/mm/page_counter.c~mm-page_counter-let-page_counter_try_charge-return-bool
+++ a/mm/page_counter.c
@@ -56,12 +56,12 @@ void page_counter_charge(struct page_cou
* @nr_pages: number of pages to charge
* @fail: points first counter to hit its limit, if any
*
- * Returns 0 on success, or -ENOMEM and @fail if the counter or one of
- * its ancestors has hit its configured limit.
+ * Returns %true on success, or %false and @fail if the counter or one
+ * of its ancestors has hit its configured limit.
*/
-int page_counter_try_charge(struct page_counter *counter,
- unsigned long nr_pages,
- struct page_counter **fail)
+bool page_counter_try_charge(struct page_counter *counter,
+ unsigned long nr_pages,
+ struct page_counter **fail)
{
struct page_counter *c;
@@ -99,13 +99,13 @@ int page_counter_try_charge(struct page_
if (new > c->watermark)
c->watermark = new;
}
- return 0;
+ return true;
failed:
for (c = counter; c != *fail; c = c->parent)
page_counter_cancel(c, nr_pages);
- return -ENOMEM;
+ return false;
}
/**
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
memcg-unify-slab-and-other-kmem-pages-charging-fix.patch
mm-memcontrol-eliminate-root-memorycurrent.patch
mm-page_counter-let-page_counter_try_charge-return-bool.patch
mm-increase-swap_cluster_max-to-batch-tlb-flushes-fix.patch
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