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[174.93.75.200]) by smtp.gmail.com with ESMTPSA id d21sm2257461qtn.24.2021.06.10.07.48.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Jun 2021 07:48:33 -0700 (PDT) Date: Thu, 10 Jun 2021 10:48:31 -0400 From: Peter Xu To: Hugh Dickins Cc: Andrew Morton , "Kirill A. Shutemov" , Yang Shi , Wang Yugui , Matthew Wilcox , Alistair Popple , Ralph Campbell , Zi Yan , Will Deacon , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 05/11] mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block Message-ID: References: <589b358c-febc-c88e-d4c2-7834b37fa7bf@google.com> <378c8650-1488-2edf-9647-32a53cf2e21@google.com> MIME-Version: 1.0 In-Reply-To: <378c8650-1488-2edf-9647-32a53cf2e21@google.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=I8OqZYZO; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf06.hostedemail.com: domain of peterx@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=peterx@redhat.com X-Stat-Signature: bannym5g7bkqb5iz3qy78919i1ku9e9k X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 68C65C00F787 X-HE-Tag: 1623336511-732798 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jun 09, 2021 at 11:42:12PM -0700, Hugh Dickins wrote: > page_vma_mapped_walk() cleanup: rearrange the !pmd_present() block to > follow the same "return not_found, return not_found, return true" pattern > as the block above it (note: returning not_found there is never premature, > since existence or prior existence of huge pmd guarantees good alignment). > > Signed-off-by: Hugh Dickins > Cc: > --- > mm/page_vma_mapped.c | 30 ++++++++++++++---------------- > 1 file changed, 14 insertions(+), 16 deletions(-) > > diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c > index 81000dd0b5da..b96fae568bc2 100644 > --- a/mm/page_vma_mapped.c > +++ b/mm/page_vma_mapped.c > @@ -201,24 +201,22 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) > if (pmd_page(pmde) != page) > return not_found(pvmw); > return true; > - } else if (!pmd_present(pmde)) { > - if (thp_migration_supported()) { > - if (!(pvmw->flags & PVMW_MIGRATION)) > - return not_found(pvmw); > - if (is_migration_entry(pmd_to_swp_entry(pmde))) { > - swp_entry_t entry = pmd_to_swp_entry(pmde); > + } > + if (!pmd_present(pmde)) { > + swp_entry_t entry; > > - if (migration_entry_to_page(entry) != page) > - return not_found(pvmw); > - return true; > - } > - } > - return not_found(pvmw); > - } else { > - /* THP pmd was split under us: handle on pte level */ > - spin_unlock(pvmw->ptl); > - pvmw->ptl = NULL; > + if (!thp_migration_supported() || > + !(pvmw->flags & PVMW_MIGRATION)) > + return not_found(pvmw); > + entry = pmd_to_swp_entry(pmde); > + if (!is_migration_entry(entry) || > + migration_entry_to_page(entry) != page) We'll need to do s/migration_entry_to_page/pfn_swap_entry_to_page/, depending on whether Alistair's series lands first or not I guess (as you mentioned in the cover letter). Thanks for the change, it does look much better. Reviewed-by: Peter Xu > + return not_found(pvmw); > + return true; > } > + /* THP pmd was split under us: handle on pte level */ > + spin_unlock(pvmw->ptl); > + pvmw->ptl = NULL; > } else if (!pmd_present(pmde)) { > /* > * If PVMW_SYNC, take and drop THP pmd lock so that we > -- > 2.26.2 > -- Peter Xu