From: Alex Shi <alex.shi@linux.alibaba.com> To: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org>, Vladimir Davydov <vdavydov.dev@gmail.com>, Andrew Morton <akpm@linux-foundation.org>, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm/memcg: remove useless check on page->mem_cgroup Date: Fri, 31 Jul 2020 11:34:40 +0800 [thread overview] Message-ID: <1596166480-22814-1-git-send-email-alex.shi@linux.alibaba.com> (raw) Since readahead page will be charged on memcg too. We don't need to check this exception now. Rmove them is safe as all user pages are charged before use. Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: cgroups@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/memcontrol.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e84c2b5596f2..9e44ae22d591 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1322,12 +1322,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd } memcg = page->mem_cgroup; - /* - * Swapcache readahead pages are added to the LRU - and - * possibly migrated - before they are charged. - */ - if (!memcg) - memcg = root_mem_cgroup; + VM_BUG_ON_PAGE(!memcg, page); mz = mem_cgroup_page_nodeinfo(memcg, page); lruvec = &mz->lruvec; @@ -6897,10 +6892,8 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage) if (newpage->mem_cgroup) return; - /* Swapcache readahead pages can get replaced before being charged */ memcg = oldpage->mem_cgroup; - if (!memcg) - return; + VM_BUG_ON_PAGE(!memcg, oldpage); /* Force-charge the new page. The old one will be freed soon */ nr_pages = thp_nr_pages(newpage); @@ -7094,10 +7087,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) return; memcg = page->mem_cgroup; - - /* Readahead page, never charged */ - if (!memcg) - return; + VM_BUG_ON_PAGE(!memcg, page); /* * In case the memcg owning these pages has been offlined and doesn't @@ -7158,10 +7148,7 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) return 0; memcg = page->mem_cgroup; - - /* Readahead page, never charged */ - if (!memcg) - return 0; + VM_BUG_ON_PAGE(!memcg, page); if (!entry.val) { memcg_memory_event(memcg, MEMCG_SWAP_FAIL); -- 1.8.3.1
WARNING: multiple messages have this Message-ID (diff)
From: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> To: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org> Cc: Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Vladimir Davydov <vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: [PATCH] mm/memcg: remove useless check on page->mem_cgroup Date: Fri, 31 Jul 2020 11:34:40 +0800 [thread overview] Message-ID: <1596166480-22814-1-git-send-email-alex.shi@linux.alibaba.com> (raw) Since readahead page will be charged on memcg too. We don't need to check this exception now. Rmove them is safe as all user pages are charged before use. Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org> Cc: Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Cc: Vladimir Davydov <vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org --- mm/memcontrol.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e84c2b5596f2..9e44ae22d591 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1322,12 +1322,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd } memcg = page->mem_cgroup; - /* - * Swapcache readahead pages are added to the LRU - and - * possibly migrated - before they are charged. - */ - if (!memcg) - memcg = root_mem_cgroup; + VM_BUG_ON_PAGE(!memcg, page); mz = mem_cgroup_page_nodeinfo(memcg, page); lruvec = &mz->lruvec; @@ -6897,10 +6892,8 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage) if (newpage->mem_cgroup) return; - /* Swapcache readahead pages can get replaced before being charged */ memcg = oldpage->mem_cgroup; - if (!memcg) - return; + VM_BUG_ON_PAGE(!memcg, oldpage); /* Force-charge the new page. The old one will be freed soon */ nr_pages = thp_nr_pages(newpage); @@ -7094,10 +7087,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) return; memcg = page->mem_cgroup; - - /* Readahead page, never charged */ - if (!memcg) - return; + VM_BUG_ON_PAGE(!memcg, page); /* * In case the memcg owning these pages has been offlined and doesn't @@ -7158,10 +7148,7 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) return 0; memcg = page->mem_cgroup; - - /* Readahead page, never charged */ - if (!memcg) - return 0; + VM_BUG_ON_PAGE(!memcg, page); if (!entry.val) { memcg_memory_event(memcg, MEMCG_SWAP_FAIL); -- 1.8.3.1
next reply other threads:[~2020-07-31 3:34 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-31 3:34 Alex Shi [this message] 2020-07-31 3:34 ` [PATCH] mm/memcg: remove useless check on page->mem_cgroup Alex Shi 2020-07-31 15:16 ` Johannes Weiner 2020-07-31 15:16 ` Johannes Weiner 2020-08-01 3:58 ` Alex Shi 2020-08-01 3:58 ` Alex Shi 2020-08-03 8:18 ` Michal Hocko 2020-08-03 8:18 ` Michal Hocko 2020-08-04 7:35 ` Alex Shi 2020-08-04 7:35 ` Alex Shi 2020-08-05 12:28 ` Alex Shi 2020-08-05 13:02 ` Alex Shi 2020-08-08 13:22 ` Alex Shi 2020-08-08 13:22 ` Alex Shi 2020-08-08 21:43 ` Roman Gushchin 2020-08-08 21:43 ` Roman Gushchin 2020-08-10 7:44 ` Alex Shi 2020-08-10 7:44 ` Alex Shi 2020-08-10 9:52 ` Michal Hocko 2020-08-10 9:52 ` Michal Hocko 2020-08-10 9:53 ` Michal Hocko 2020-08-10 9:53 ` Michal Hocko 2020-08-10 9:55 ` Michal Hocko 2020-08-10 9:55 ` Michal Hocko 2020-08-10 12:29 ` Alex Shi 2020-08-10 12:29 ` Alex Shi
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