From: Yu Zhao <yuzhao@google.com> To: Michal Hocko <mhocko@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, Andi Kleen <ak@linux.intel.com>, Catalin Marinas <catalin.marinas@arm.com>, Dave Hansen <dave.hansen@linux.intel.com>, Hillf Danton <hdanton@sina.com>, Jens Axboe <axboe@kernel.dk>, Jesse Barnes <jsbarnes@google.com>, Johannes Weiner <hannes@cmpxchg.org>, Jonathan Corbet <corbet@lwn.net>, Matthew Wilcox <willy@infradead.org>, Mel Gorman <mgorman@suse.de>, Michael Larabel <Michael@michaellarabel.com>, Rik van Riel <riel@surriel.com>, Vlastimil Babka <vbabka@suse.cz>, Will Deacon <will@kernel.org>, Ying Huang <ying.huang@intel.com>, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, page-reclaim@google.com, x86@kernel.org, Konstantin Kharlamov <Hi-Angel@yandex.ru> Subject: Re: [PATCH v6 5/9] mm: multigenerational lru: mm_struct list Date: Wed, 12 Jan 2022 01:08:14 -0700 [thread overview] Message-ID: <Yd6MbsVkU7fChCrc@google.com> (raw) In-Reply-To: <YdxPEdsfl771Z7IX@dhcp22.suse.cz> On Mon, Jan 10, 2022 at 04:21:53PM +0100, Michal Hocko wrote: > On Fri 07-01-22 17:19:28, Yu Zhao wrote: > > On Fri, Jan 07, 2022 at 10:06:15AM +0100, Michal Hocko wrote: > > > On Tue 04-01-22 13:22:24, Yu Zhao wrote: > > > > To exploit spatial locality, the aging prefers to walk page tables to > > > > search for young PTEs. And this patch paves the way for that. > > > > > > > > An mm_struct list is maintained for each memcg, and an mm_struct > > > > follows its owner task to the new memcg when this task is migrated. > > > > > > How does this work actually for the memcg reclaim? I can see you > > > lru_gen_migrate_mm on the task migration. My concern is, though, that > > > such a task leaves all the memory behind in the previous memcg (in > > > cgroup v2, in v1 you can opt in for charge migration). If you move the > > > mm to a new memcg then you age it somewhere where the memory is not > > > really consumed. > > > > There are two options to gather the accessed bit: page table walks and > > rmap walks. Page table walks sweep dense hotspots that are NOT > > misplaced in terms of reclaim scope (lruvec); rmap walks cover what > > page table walks miss, e.g., misplaced dense hotspots or sparse ones. > > > > Dense hotspots are stored in Bloom filters for each lruvec. > > > > If an mm leaves everything in the old memcg, page table walks in the > > new memcg reclaim path basically ignore this mm after the first scan, > > because everything is misplaced. > > OK, so do I get it right that pages mapped from a different memcg than > the reclaimed one are considered effectivelly non-present from the the > reclaim logic POV? This would be worth mentioning in the migration > callback because it is not really that straightforward to put those two > together. That's correct. Will document this in detail. > > In the old memcg reclaim path, page table walks won't see this mm > > at all. But rmap walks will catch everything later in the eviction > > path, i.e., lru_gen_look_around(). This function is less efficient > > compared with page table walks because, for each rmap walk of a > > non-shared page, it only can gather the accessed bit from 64 PTEs at > > most. But it's still a lot faster than the original rmap, which only > > gathers the accessed bit from a single PTE, for each walk of a > > non-shared page. > > Again, something that should be really documented. Noted.
WARNING: multiple messages have this Message-ID (diff)
From: Yu Zhao <yuzhao@google.com> To: Michal Hocko <mhocko@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, Andi Kleen <ak@linux.intel.com>, Catalin Marinas <catalin.marinas@arm.com>, Dave Hansen <dave.hansen@linux.intel.com>, Hillf Danton <hdanton@sina.com>, Jens Axboe <axboe@kernel.dk>, Jesse Barnes <jsbarnes@google.com>, Johannes Weiner <hannes@cmpxchg.org>, Jonathan Corbet <corbet@lwn.net>, Matthew Wilcox <willy@infradead.org>, Mel Gorman <mgorman@suse.de>, Michael Larabel <Michael@michaellarabel.com>, Rik van Riel <riel@surriel.com>, Vlastimil Babka <vbabka@suse.cz>, Will Deacon <will@kernel.org>, Ying Huang <ying.huang@intel.com>, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, page-reclaim@google.com, x86@kernel.org, Konstantin Kharlamov <Hi-Angel@yandex.ru> Subject: Re: [PATCH v6 5/9] mm: multigenerational lru: mm_struct list Date: Wed, 12 Jan 2022 01:08:14 -0700 [thread overview] Message-ID: <Yd6MbsVkU7fChCrc@google.com> (raw) In-Reply-To: <YdxPEdsfl771Z7IX@dhcp22.suse.cz> On Mon, Jan 10, 2022 at 04:21:53PM +0100, Michal Hocko wrote: > On Fri 07-01-22 17:19:28, Yu Zhao wrote: > > On Fri, Jan 07, 2022 at 10:06:15AM +0100, Michal Hocko wrote: > > > On Tue 04-01-22 13:22:24, Yu Zhao wrote: > > > > To exploit spatial locality, the aging prefers to walk page tables to > > > > search for young PTEs. And this patch paves the way for that. > > > > > > > > An mm_struct list is maintained for each memcg, and an mm_struct > > > > follows its owner task to the new memcg when this task is migrated. > > > > > > How does this work actually for the memcg reclaim? I can see you > > > lru_gen_migrate_mm on the task migration. My concern is, though, that > > > such a task leaves all the memory behind in the previous memcg (in > > > cgroup v2, in v1 you can opt in for charge migration). If you move the > > > mm to a new memcg then you age it somewhere where the memory is not > > > really consumed. > > > > There are two options to gather the accessed bit: page table walks and > > rmap walks. Page table walks sweep dense hotspots that are NOT > > misplaced in terms of reclaim scope (lruvec); rmap walks cover what > > page table walks miss, e.g., misplaced dense hotspots or sparse ones. > > > > Dense hotspots are stored in Bloom filters for each lruvec. > > > > If an mm leaves everything in the old memcg, page table walks in the > > new memcg reclaim path basically ignore this mm after the first scan, > > because everything is misplaced. > > OK, so do I get it right that pages mapped from a different memcg than > the reclaimed one are considered effectivelly non-present from the the > reclaim logic POV? This would be worth mentioning in the migration > callback because it is not really that straightforward to put those two > together. That's correct. Will document this in detail. > > In the old memcg reclaim path, page table walks won't see this mm > > at all. But rmap walks will catch everything later in the eviction > > path, i.e., lru_gen_look_around(). This function is less efficient > > compared with page table walks because, for each rmap walk of a > > non-shared page, it only can gather the accessed bit from 64 PTEs at > > most. But it's still a lot faster than the original rmap, which only > > gathers the accessed bit from a single PTE, for each walk of a > > non-shared page. > > Again, something that should be really documented. Noted. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-01-12 8:08 UTC|newest] Thread overview: 223+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-04 20:22 [PATCH v6 0/9] Multigenerational LRU Framework Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-04 20:22 ` [PATCH v6 1/9] mm: x86, arm64: add arch_has_hw_pte_young() Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-05 10:45 ` Will Deacon 2022-01-05 10:45 ` Will Deacon 2022-01-05 20:47 ` Yu Zhao 2022-01-05 20:47 ` Yu Zhao 2022-01-06 10:30 ` Will Deacon 2022-01-06 10:30 ` Will Deacon 2022-01-07 7:25 ` Yu Zhao 2022-01-07 7:25 ` Yu Zhao 2022-01-11 14:19 ` Will Deacon 2022-01-11 14:19 ` Will Deacon 2022-01-11 22:27 ` Yu Zhao 2022-01-11 22:27 ` Yu Zhao 2022-01-04 20:22 ` [PATCH v6 2/9] mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-04 21:24 ` Linus Torvalds 2022-01-04 21:24 ` Linus Torvalds 2022-01-04 20:22 ` [PATCH v6 3/9] mm/vmscan.c: refactor shrink_node() Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-04 20:22 ` [PATCH v6 4/9] mm: multigenerational lru: groundwork Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-04 21:34 ` Linus Torvalds 2022-01-04 21:34 ` Linus Torvalds 2022-01-11 8:16 ` Aneesh Kumar K.V 2022-01-11 8:16 ` Aneesh Kumar K.V 2022-01-12 2:16 ` Yu Zhao 2022-01-12 2:16 ` Yu Zhao 2022-01-04 20:22 ` [PATCH v6 5/9] mm: multigenerational lru: mm_struct list Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-07 9:06 ` Michal Hocko 2022-01-07 9:06 ` Michal Hocko 2022-01-08 0:19 ` Yu Zhao 2022-01-08 0:19 ` Yu Zhao 2022-01-10 15:21 ` Michal Hocko 2022-01-10 15:21 ` Michal Hocko 2022-01-12 8:08 ` Yu Zhao [this message] 2022-01-12 8:08 ` Yu Zhao 2022-01-04 20:22 ` [PATCH v6 6/9] mm: multigenerational lru: aging Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-06 16:06 ` Michal Hocko 2022-01-06 16:06 ` Michal Hocko 2022-01-06 21:27 ` Yu Zhao 2022-01-06 21:27 ` Yu Zhao 2022-01-07 8:43 ` Michal Hocko 2022-01-07 8:43 ` Michal Hocko 2022-01-07 21:12 ` Yu Zhao 2022-01-07 21:12 ` Yu Zhao 2022-01-06 16:12 ` Michal Hocko 2022-01-06 16:12 ` Michal Hocko 2022-01-06 21:41 ` Yu Zhao 2022-01-06 21:41 ` Yu Zhao 2022-01-07 8:55 ` Michal Hocko 2022-01-07 8:55 ` Michal Hocko 2022-01-07 9:00 ` Michal Hocko 2022-01-07 9:00 ` Michal Hocko 2022-01-10 3:58 ` Yu Zhao 2022-01-10 3:58 ` Yu Zhao 2022-01-10 14:37 ` Michal Hocko 2022-01-10 14:37 ` Michal Hocko 2022-01-13 9:43 ` Yu Zhao 2022-01-13 9:43 ` Yu Zhao 2022-01-13 12:02 ` Michal Hocko 2022-01-13 12:02 ` Michal Hocko 2022-01-19 6:31 ` Yu Zhao 2022-01-19 6:31 ` Yu Zhao 2022-01-19 9:44 ` Michal Hocko 2022-01-19 9:44 ` Michal Hocko 2022-01-10 15:01 ` Michal Hocko 2022-01-10 15:01 ` Michal Hocko 2022-01-10 16:01 ` Vlastimil Babka 2022-01-10 16:01 ` Vlastimil Babka 2022-01-10 16:25 ` Michal Hocko 2022-01-10 16:25 ` Michal Hocko 2022-01-11 23:16 ` Yu Zhao 2022-01-11 23:16 ` Yu Zhao 2022-01-12 10:28 ` Michal Hocko 2022-01-12 10:28 ` Michal Hocko 2022-01-13 9:25 ` Yu Zhao 2022-01-13 9:25 ` Yu Zhao 2022-01-07 13:11 ` Michal Hocko 2022-01-07 13:11 ` Michal Hocko 2022-01-07 23:36 ` Yu Zhao 2022-01-07 23:36 ` Yu Zhao 2022-01-10 15:35 ` Michal Hocko 2022-01-10 15:35 ` Michal Hocko 2022-01-11 1:18 ` Yu Zhao 2022-01-11 1:18 ` Yu Zhao 2022-01-11 9:00 ` Michal Hocko 2022-01-11 9:00 ` Michal Hocko [not found] ` <1641900108.61dd684cb0e59@mail.inbox.lv> 2022-01-11 12:15 ` Michal Hocko 2022-01-11 12:15 ` Michal Hocko 2022-01-13 17:00 ` Alexey Avramov 2022-01-13 17:00 ` Alexey Avramov 2022-01-11 14:22 ` Alexey Avramov 2022-01-11 14:22 ` Alexey Avramov 2022-01-07 14:44 ` Michal Hocko 2022-01-07 14:44 ` Michal Hocko 2022-01-10 4:47 ` Yu Zhao 2022-01-10 4:47 ` Yu Zhao 2022-01-10 10:54 ` Michal Hocko 2022-01-10 10:54 ` Michal Hocko 2022-01-19 7:04 ` Yu Zhao 2022-01-19 7:04 ` Yu Zhao 2022-01-19 9:42 ` Michal Hocko 2022-01-19 9:42 ` Michal Hocko 2022-01-23 21:28 ` Yu Zhao 2022-01-23 21:28 ` Yu Zhao 2022-01-24 14:01 ` Michal Hocko 2022-01-24 14:01 ` Michal Hocko 2022-01-10 16:57 ` Michal Hocko 2022-01-10 16:57 ` Michal Hocko 2022-01-12 1:01 ` Yu Zhao 2022-01-12 1:01 ` Yu Zhao 2022-01-12 10:17 ` Michal Hocko 2022-01-12 10:17 ` Michal Hocko 2022-01-12 23:43 ` Yu Zhao 2022-01-12 23:43 ` Yu Zhao 2022-01-13 11:57 ` Michal Hocko 2022-01-13 11:57 ` Michal Hocko 2022-01-23 21:40 ` Yu Zhao 2022-01-23 21:40 ` Yu Zhao 2022-01-04 20:22 ` [PATCH v6 7/9] mm: multigenerational lru: eviction Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-11 10:37 ` Aneesh Kumar K.V 2022-01-11 10:37 ` Aneesh Kumar K.V 2022-01-12 8:05 ` Yu Zhao 2022-01-12 8:05 ` Yu Zhao 2022-01-04 20:22 ` [PATCH v6 8/9] mm: multigenerational lru: user interface Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-10 10:27 ` Mike Rapoport 2022-01-10 10:27 ` Mike Rapoport 2022-01-12 8:35 ` Yu Zhao 2022-01-12 8:35 ` Yu Zhao 2022-01-12 10:31 ` Michal Hocko 2022-01-12 10:31 ` Michal Hocko 2022-01-12 15:45 ` Mike Rapoport 2022-01-12 15:45 ` Mike Rapoport 2022-01-13 9:47 ` Yu Zhao 2022-01-13 9:47 ` Yu Zhao 2022-01-13 10:31 ` Aneesh Kumar K.V 2022-01-13 10:31 ` Aneesh Kumar K.V 2022-01-13 23:02 ` Yu Zhao 2022-01-13 23:02 ` Yu Zhao 2022-01-14 5:20 ` Aneesh Kumar K.V 2022-01-14 5:20 ` Aneesh Kumar K.V 2022-01-14 6:50 ` Yu Zhao 2022-01-14 6:50 ` Yu Zhao 2022-01-04 20:22 ` [PATCH v6 9/9] mm: multigenerational lru: Kconfig Yu Zhao 2022-01-04 20:22 ` Yu Zhao 2022-01-04 21:39 ` Linus Torvalds 2022-01-04 21:39 ` Linus Torvalds 2022-01-04 20:22 ` [PATCH v6 0/9] Multigenerational LRU Framework Yu Zhao 2022-01-04 20:30 ` Yu Zhao 2022-01-04 20:30 ` Yu Zhao 2022-01-04 21:43 ` Linus Torvalds 2022-01-04 21:43 ` Linus Torvalds 2022-01-05 21:12 ` Yu Zhao 2022-01-05 21:12 ` Yu Zhao 2022-01-07 9:38 ` Michal Hocko 2022-01-07 9:38 ` Michal Hocko 2022-01-07 18:45 ` Yu Zhao 2022-01-07 18:45 ` Yu Zhao 2022-01-10 15:39 ` Michal Hocko 2022-01-10 15:39 ` Michal Hocko 2022-01-10 22:04 ` Yu Zhao 2022-01-10 22:04 ` Yu Zhao 2022-01-10 22:46 ` Jesse Barnes 2022-01-10 22:46 ` Jesse Barnes 2022-01-11 1:41 ` Linus Torvalds 2022-01-11 1:41 ` Linus Torvalds 2022-01-11 10:40 ` Michal Hocko 2022-01-11 10:40 ` Michal Hocko 2022-01-11 8:41 ` Yu Zhao 2022-01-11 8:41 ` Yu Zhao 2022-01-11 8:53 ` Holger Hoffstätte 2022-01-11 8:53 ` Holger Hoffstätte 2022-01-11 9:26 ` Jan Alexander Steffens (heftig) 2022-01-11 16:04 ` Shuang Zhai 2022-01-11 16:04 ` Shuang Zhai 2022-01-12 1:46 ` Suleiman Souhlal 2022-01-12 1:46 ` Suleiman Souhlal 2022-01-12 6:07 ` Sofia Trinh 2022-01-12 6:07 ` Sofia Trinh 2022-01-12 16:17 ` Daniel Byrne 2022-01-18 9:21 ` Yu Zhao 2022-01-18 9:21 ` Yu Zhao 2022-01-18 9:36 ` Donald Carr 2022-01-18 9:36 ` Donald Carr 2022-01-19 20:19 ` Steven Barrett 2022-01-19 20:19 ` Steven Barrett 2022-01-19 22:25 ` Brian Geffon 2022-01-19 22:25 ` Brian Geffon 2022-01-05 2:44 ` Shuang Zhai 2022-01-05 2:44 ` Shuang Zhai 2022-01-05 8:55 ` SeongJae Park 2022-01-05 8:55 ` SeongJae Park 2022-01-05 10:53 ` Yu Zhao 2022-01-05 10:53 ` Yu Zhao 2022-01-05 11:12 ` Borislav Petkov 2022-01-05 11:12 ` Borislav Petkov 2022-01-05 11:25 ` SeongJae Park 2022-01-05 11:25 ` SeongJae Park 2022-01-05 21:06 ` Yu Zhao 2022-01-05 21:06 ` Yu Zhao 2022-01-10 14:49 ` Alexey Avramov 2022-01-10 14:49 ` Alexey Avramov 2022-01-11 10:24 ` Alexey Avramov 2022-01-11 10:24 ` Alexey Avramov 2022-01-12 20:56 ` Oleksandr Natalenko 2022-01-12 20:56 ` Oleksandr Natalenko 2022-01-13 8:59 ` Yu Zhao 2022-01-13 8:59 ` Yu Zhao 2022-01-23 5:43 ` Barry Song 2022-01-23 5:43 ` Barry Song 2022-01-25 6:48 ` Yu Zhao 2022-01-25 6:48 ` Yu Zhao 2022-01-28 8:54 ` Barry Song 2022-01-28 8:54 ` Barry Song 2022-02-08 9:16 ` Yu Zhao 2022-02-08 9:16 ` Yu Zhao
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