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mm, hugetlb_cgroup: round limit_in_bytes down to hugepage size

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The page_counter rounds limits down to page size values.  This makes
sense, except in the case of hugetlb_cgroup where it's not possible to
charge partial hugepages.  If the hugetlb_cgroup margin is less than the
hugepage size being charged, it will fail as expected.

Round the hugetlb_cgroup limit down to hugepage size, since it is the
effective limit of the cgroup.

For consistency, round down PAGE_COUNTER_MAX as well when a
hugetlb_cgroup is created: this prevents error reports when a user
cannot restore the value to the kernel default.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Nikolay Borisov <kernel@kyup.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Rientjes 2016-05-20 16:57:50 -07:00 committed by Linus Torvalds
parent 63678c32e2
commit 297880f4af
1 changed files with 26 additions and 9 deletions
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35
mm/hugetlb_cgroup.c
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@ -67,26 +67,42 @@ static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg)
return false;
}
static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup,
struct hugetlb_cgroup *parent_h_cgroup)
{
int idx;
for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) {
struct page_counter *counter = &h_cgroup->hugepage[idx];
struct page_counter *parent = NULL;
unsigned long limit;
int ret;
if (parent_h_cgroup)
parent = &parent_h_cgroup->hugepage[idx];
page_counter_init(counter, parent);
limit = round_down(PAGE_COUNTER_MAX,
1 << huge_page_order(&hstates[idx]));
ret = page_counter_limit(counter, limit);
VM_BUG_ON(ret);
}
}
static struct cgroup_subsys_state *
hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css);
struct hugetlb_cgroup *h_cgroup;
int idx;
h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
if (!h_cgroup)
return ERR_PTR(-ENOMEM);
if (parent_h_cgroup) {
for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
page_counter_init(&h_cgroup->hugepage[idx],
&parent_h_cgroup->hugepage[idx]);
} else {
if (!parent_h_cgroup)
root_h_cgroup = h_cgroup;
for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
page_counter_init(&h_cgroup->hugepage[idx], NULL);
}
hugetlb_cgroup_init(h_cgroup, parent_h_cgroup);
return &h_cgroup->css;
}
@ -285,6 +301,7 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
return ret;
idx = MEMFILE_IDX(of_cft(of)->private);
nr_pages = round_down(nr_pages, 1 << huge_page_order(&hstates[idx]));
switch (MEMFILE_ATTR(of_cft(of)->private)) {
case RES_LIMIT: