Messages in this thread | | | From | Shakeel Butt <> | Date | Thu, 4 Mar 2021 10:55:03 -0800 | Subject | Re: [PATCH v2 2/2] mm/memcg: set memcg when split page |
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On Wed, Mar 3, 2021 at 11:57 PM Zhou Guanghui <zhouguanghui1@huawei.com> wrote: > > As described in the split_page function comment, for the non-compound > high order page, the sub-pages must be freed individually. If the > memcg of the fisrt page is valid, the tail pages cannot be uncharged > when be freed. > > For example, when alloc_pages_exact is used to allocate 1MB continuous > physical memory, 2MB is charged(kmemcg is enabled and __GFP_ACCOUNT is > set). When make_alloc_exact free the unused 1MB and free_pages_exact > free the applied 1MB, actually, only 4KB(one page) is uncharged. > > Therefore, the memcg of the tail page needs to be set when split page. > > Signed-off-by: Zhou Guanghui <zhouguanghui1@huawei.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
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