Re: [PATCH 02/23] memcg, thp: charge huge cache pages
From: Michal Hocko <hidden>
Date: 2013-08-04 08:25:09
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On Sun 04-08-13 05:17:04, Kirill A. Shutemov wrote:
From: "Kirill A. Shutemov" <redacted> mem_cgroup_cache_charge() has check for PageCompound(). The check prevents charging huge cache pages. I don't see a reason why the check is present. Looks like it's just legacy (introduced in 52d4b9a memcg: allocate all page_cgroup at boot). Let's just drop it.
If the page cache charging path only sees THP as compound pages then OK. Can we keep at least VM_BUG_ON(PageCompound(page) && !PageTransHuge(page)) Otherwise mem_cgroup_charge_common would be confused and charge such a page as order-0
Signed-off-by: Kirill A. Shutemov <redacted> Cc: Michal Hocko <redacted> Cc: KAMEZAWA Hiroyuki <redacted> Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Other than that, looks good to me. Acked-by: Michal Hocko <redacted>
quoted hunk ↗ jump to hunk
--- mm/memcontrol.c | 2 -- 1 file changed, 2 deletions(-)diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b6cd870..dc50c1a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c@@ -3921,8 +3921,6 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, if (mem_cgroup_disabled()) return 0; - if (PageCompound(page)) - return 0; if (!PageSwapCache(page)) ret = mem_cgroup_charge_common(page, mm, gfp_mask, type);-- 1.8.3.2
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