From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f71.google.com (mail-oi0-f71.google.com [209.85.218.71]) by kanga.kvack.org (Postfix) with ESMTP id 5961A6B0655 for ; Fri, 18 May 2018 13:46:53 -0400 (EDT) Received: by mail-oi0-f71.google.com with SMTP id e2-v6so5567687oii.20 for ; Fri, 18 May 2018 10:46:53 -0700 (PDT) Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id s8-v6si2880816ota.184.2018.05.18.10.46.52 for ; Fri, 18 May 2018 10:46:52 -0700 (PDT) From: Punit Agrawal Subject: Re: [PATCH v2 3/7] memcg: use compound_order rather than hpage_nr_pages References: <262267fe-d98c-0b25-9013-3dafb52e8679@ascade.co.jp> Date: Fri, 18 May 2018 18:46:49 +0100 In-Reply-To: <262267fe-d98c-0b25-9013-3dafb52e8679@ascade.co.jp> (TSUKADA Koutaro's message of "Fri, 18 May 2018 13:34:26 +0900") Message-ID: <87wow0zwja.fsf@e105922-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: TSUKADA Koutaro Cc: Johannes Weiner , Michal Hocko , Vladimir Davydov , Jonathan Corbet , "Luis R. Rodriguez" , Kees Cook , Andrew Morton , Roman Gushchin , David Rientjes , Mike Kravetz , "Aneesh Kumar K.V" , Naoya Horiguchi , Anshuman Khandual , Marc-Andre Lureau , Dan Williams , Vlastimil Babka , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org Tsukada-san, I am not familiar with memcg so can't comment about whether the patchset is the right way to solve the problem outlined in the cover letter but had a couple of comments about this patch. TSUKADA Koutaro writes: > The current memcg implementation assumes that the compound page is THP. > In order to be able to charge surplus hugepage, we use compound_order. > > Signed-off-by: TSUKADA Koutaro Please move this before Patch 1/7. This is to prevent wrong accounting of pages to memcg for size != PMD_SIZE. > --- > memcontrol.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 2bd3df3..a8f1ff8 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -4483,7 +4483,7 @@ static int mem_cgroup_move_account(struct page *page, > struct mem_cgroup *to) > { > unsigned long flags; > - unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1; > + unsigned int nr_pages = compound ? (1 << compound_order(page)) : 1; Instead of replacing calls to hpage_nr_pages(), is it possible to modify it to do the calculation? Thanks, Punit > int ret; > bool anon; > > @@ -5417,7 +5417,7 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, > bool compound) > { > struct mem_cgroup *memcg = NULL; > - unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1; > + unsigned int nr_pages = compound ? (1 << compound_order(page)) : 1; > int ret = 0; > > if (mem_cgroup_disabled()) > @@ -5478,7 +5478,7 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, > void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg, > bool lrucare, bool compound) > { > - unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1; > + unsigned int nr_pages = compound ? (1 << compound_order(page)) : 1; > > VM_BUG_ON_PAGE(!page->mapping, page); > VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page); > @@ -5522,7 +5522,7 @@ void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg, > void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg, > bool compound) > { > - unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1; > + unsigned int nr_pages = compound ? (1 << compound_order(page)) : 1; > > if (mem_cgroup_disabled()) > return; > @@ -5729,7 +5729,7 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage) > > /* Force-charge the new page. The old one will be freed soon */ > compound = PageTransHuge(newpage); > - nr_pages = compound ? hpage_nr_pages(newpage) : 1; > + nr_pages = compound ? (1 << compound_order(newpage)) : 1; > > page_counter_charge(&memcg->memory, nr_pages); > if (do_memsw_account())