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Commit 6071ca52 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

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: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f5fc3c5d

include/linux/page_counter.h

+3 −3
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ static inline unsigned long page_counter_read(struct page_counter *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,

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);

mm/hugetlb_cgroup.c

+2 −1
Original line number Diff line number Diff line
@@ -186,7 +186,8 @@ int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, 
	}

	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;

mm/memcontrol.c

+5 −6
Original line number Diff line number Diff line
@@ -2016,8 +2016,8 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, 
		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 page *page, gfp_t gfp, int order, 
{

	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) {

mm/page_counter.c

+7 −7
Original line number Diff line number Diff line
@@ -56,10 +56,10 @@ void page_counter_charge(struct page_counter *counter, unsigned long nr_pages) 
 * @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,

bool page_counter_try_charge(struct page_counter *counter,

			     unsigned long nr_pages,

			     struct page_counter **fail)

{
@@ -99,13 +99,13 @@ int page_counter_try_charge(struct page_counter *counter, 
		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;

}



/**