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Shutemov" , Matthew Wilcox , Vlastimil Babka , Jann Horn , Michal Hocko , Nadav Amit , Rik van Riel , Roman Gushchin , Andrea Arcangeli , Peter Xu , Donald Dutile , Christoph Hellwig , Oleg Nesterov , Jan Kara , Liang Zhang , Pedro Gomes , Oded Gabbay , Catalin Marinas , Will Deacon , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , linux-mm@kvack.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org Subject: Re: [PATCH v1 0/7] mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages Message-ID: <20220318234850.GD11336@nvidia.com> References: <20220315141837.137118-1-david@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220315141837.137118-1-david@redhat.com> X-ClientProxiedBy: BL0PR01CA0035.prod.exchangelabs.com (2603:10b6:208:71::48) To MN2PR12MB4192.namprd12.prod.outlook.com (2603:10b6:208:1d5::15) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: edaf932c-7fe5-4aa3-62a0-08da0939da98 X-MS-TrafficTypeDiagnostic: SN6PR12MB2607:EE_|BYAPR12MB3511:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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Fixing O_DIRECT is just a > nice side-product :) I know I would benefit alot from a description of the swap specific issue a bit more. Most of this message talks about clear_refs which I do understand a bit better. Is this talking about what happens after a page gets swapped back in? eg the exclusive bit is missing when the page is recreated? Otherwise nothing stood out to me here, but I know almost nothing about swap. 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Shutemov" , Mike Kravetz Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Mar 15, 2022 at 03:18:30PM +0100, David Hildenbrand wrote: > This is just the natural follow-up of part 2, that will also further > reduce "wrong COW" on the swapin path, for example, when we cannot remove > a page from the swapcache due to concurrent writeback, or if we have two > threads faulting on the same swapped-out page. Fixing O_DIRECT is just a > nice side-product :) I know I would benefit alot from a description of the swap specific issue a bit more. Most of this message talks about clear_refs which I do understand a bit better. Is this talking about what happens after a page gets swapped back in? eg the exclusive bit is missing when the page is recreated? Otherwise nothing stood out to me here, but I know almost nothing about swap. 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Shutemov" , Matthew Wilcox , Vlastimil Babka , Jann Horn , Michal Hocko , Nadav Amit , Rik van Riel , Roman Gushchin , Andrea Arcangeli , Peter Xu , Donald Dutile , Christoph Hellwig , Oleg Nesterov , Jan Kara , Liang Zhang , Pedro Gomes , Oded Gabbay , Catalin Marinas , Will Deacon , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , linux-mm@kvack.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org Subject: Re: [PATCH v1 0/7] mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages Message-ID: <20220318234850.GD11336@nvidia.com> References: <20220315141837.137118-1-david@redhat.com> Content-Disposition: inline In-Reply-To: <20220315141837.137118-1-david@redhat.com> X-ClientProxiedBy: BL0PR01CA0035.prod.exchangelabs.com (2603:10b6:208:71::48) To MN2PR12MB4192.namprd12.prod.outlook.com (2603:10b6:208:1d5::15) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: edaf932c-7fe5-4aa3-62a0-08da0939da98 X-MS-TrafficTypeDiagnostic: SN6PR12MB2607:EE_|BYAPR12MB3511:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Mar 15, 2022 at 03:18:30PM +0100, David Hildenbrand wrote: > This is just the natural follow-up of part 2, that will also further > reduce "wrong COW" on the swapin path, for example, when we cannot remove > a page from the swapcache due to concurrent writeback, or if we have two > threads faulting on the same swapped-out page. Fixing O_DIRECT is just a > nice side-product :) I know I would benefit alot from a description of the swap specific issue a bit more. Most of this message talks about clear_refs which I do understand a bit better. Is this talking about what happens after a page gets swapped back in? eg the exclusive bit is missing when the page is recreated? Otherwise nothing stood out to me here, but I know almost nothing about swap. Thanks, Jason _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel