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Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rVcU6-0000000GasR-0ACZ; Thu, 01 Feb 2024 19:12:26 +0000 Date: Thu, 1 Feb 2024 19:12:25 +0000 From: Matthew Wilcox To: Kefeng Wang Cc: Andrew Morton , linux-mm@kvack.org, Tony Luck , Naoya Horiguchi , Miaohe Lin , David Hildenbrand , Muchun Song , Benjamin LaHaise , jglisse@redhat.com, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH rfc 1/9] mm: migrate: simplify __buffer_migrate_folio() Message-ID: References: <20240129070934.3717659-1-wangkefeng.wang@huawei.com> <20240129070934.3717659-2-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240129070934.3717659-2-wangkefeng.wang@huawei.com> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 42F1B1C000B X-Stat-Signature: cqdrqn1f1yk9yhhrxg8wass6rmj98z8z X-HE-Tag: 1706814752-335308 X-HE-Meta: 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 lkwMKvpP BFXl5M04I2J+4hvLqa13z0PQW+wNFmfaUMjYm4ndagtTGbh78q7/JKNN9hmZx8AcTQh3s4Jt1RrPSxz4HDGvRTxRJFZUD+UUrcxHRmlB5g6BdPKOYmLJl+17pf0r3bsWopyV4GDYVBx9rwmNh9A94rxBQ6SiE8QdaxqogPHrLn3RM/6rcUtCfzbg9yRwg0tbH8PlleTsbpusyZl/z0eFPTvcXv6fTcntwbApP+av//EcuU8r55F7bhhSPniXE14FQem5OV3k/eJ2n1Lc= 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: List-Subscribe: List-Unsubscribe: On Mon, Jan 29, 2024 at 03:09:26PM +0800, Kefeng Wang wrote: > @@ -774,24 +774,16 @@ static int __buffer_migrate_folio(struct address_space *mapping, > } > } > > - rc = folio_migrate_mapping(mapping, dst, src, 0); > + rc = filemap_migrate_folio(mapping, dst, src, mode); > if (rc != MIGRATEPAGE_SUCCESS) > goto unlock_buffers; > > - folio_attach_private(dst, folio_detach_private(src)); > - > bh = head; > do { > folio_set_bh(bh, dst, bh_offset(bh)); > bh = bh->b_this_page; > } while (bh != head); > > - if (mode != MIGRATE_SYNC_NO_COPY) > - folio_migrate_copy(dst, src); > - else > - folio_migrate_flags(dst, src); > - > - rc = MIGRATEPAGE_SUCCESS; I wondered if maybe there was an ordering requirement; that we had to set up the BHs before copying the data over. But I don't think there is; the page should be frozen, the buffer heads are locked, and I don't think the ordering matters. So ... Reviewed-by: Matthew Wilcox (Oracle)