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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id b24-20020a9d5d18000000b0066da36d2c45sm9763064oti.22.2022.12.06.17.52.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Dec 2022 17:52:32 -0800 (PST) Date: Tue, 6 Dec 2022 17:52:30 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Johannes Weiner cc: Andrew Morton , Linus Torvalds , Hugh Dickins , Shakeel Butt , Michal Hocko , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] mm: rmap: remove lock_page_memcg() In-Reply-To: <20221206171340.139790-3-hannes@cmpxchg.org> Message-ID: <424a805a-28b8-afe1-ad61-f4fdc42aaa8@google.com> References: <20221206171340.139790-1-hannes@cmpxchg.org> <20221206171340.139790-3-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 6 Dec 2022, Johannes Weiner wrote: > The previous patch made sure charge moving only touches pages for > which page_mapped() is stable. lock_page_memcg() is no longer needed. > > Signed-off-by: Johannes Weiner Acked-by: Hugh Dickins > --- > mm/rmap.c | 26 ++++++++------------------ > 1 file changed, 8 insertions(+), 18 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index b616870a09be..32e48b1c5847 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -1222,9 +1222,6 @@ void page_add_anon_rmap(struct page *page, > bool compound = flags & RMAP_COMPOUND; > bool first = true; > > - if (unlikely(PageKsm(page))) > - lock_page_memcg(page); > - > /* Is page being mapped by PTE? Is this its first map to be added? */ > if (likely(!compound)) { > first = atomic_inc_and_test(&page->_mapcount); > @@ -1262,15 +1259,14 @@ void page_add_anon_rmap(struct page *page, > if (nr) > __mod_lruvec_page_state(page, NR_ANON_MAPPED, nr); > > - if (unlikely(PageKsm(page))) > - unlock_page_memcg(page); > - > - /* address might be in next vma when migration races vma_adjust */ > - else if (first) > - __page_set_anon_rmap(page, vma, address, > - !!(flags & RMAP_EXCLUSIVE)); > - else > - __page_check_anon_rmap(page, vma, address); > + if (likely(!PageKsm(page))) { > + /* address might be in next vma when migration races vma_adjust */ > + if (first) > + __page_set_anon_rmap(page, vma, address, > + !!(flags & RMAP_EXCLUSIVE)); > + else > + __page_check_anon_rmap(page, vma, address); > + } > > mlock_vma_page(page, vma, compound); > } > @@ -1329,7 +1325,6 @@ void page_add_file_rmap(struct page *page, > bool first; > > VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page); > - lock_page_memcg(page); > > /* Is page being mapped by PTE? Is this its first map to be added? */ > if (likely(!compound)) { > @@ -1365,7 +1360,6 @@ void page_add_file_rmap(struct page *page, > NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, nr_pmdmapped); > if (nr) > __mod_lruvec_page_state(page, NR_FILE_MAPPED, nr); > - unlock_page_memcg(page); > > mlock_vma_page(page, vma, compound); > } > @@ -1394,8 +1388,6 @@ void page_remove_rmap(struct page *page, > return; > } > > - lock_page_memcg(page); > - > /* Is page being unmapped by PTE? Is this its last map to be removed? */ > if (likely(!compound)) { > last = atomic_add_negative(-1, &page->_mapcount); > @@ -1451,8 +1443,6 @@ void page_remove_rmap(struct page *page, > * and remember that it's only reliable while mapped. > */ > > - unlock_page_memcg(page); > - > munlock_vma_page(page, vma, compound); > } > > -- > 2.38.1 > >