From: Michal Hocko <mhocko@kernel.org> To: Arnd Bergmann <arnd@arndb.de> Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>, Nishanth Menon <nm@ti.com>, Santosh Shilimkar <santosh.shilimkar@oracle.com>, Tero Kristo <t-kristo@ti.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Rik van Riel <riel@surriel.com>, Catalin Marinas <catalin.marinas@arm.com>, Santosh Shilimkar <ssantosh@kernel.org>, Dave Chinner <david@fromorbit.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Linux-MM <linux-mm@kvack.org>, Yafang Shao <laoar.shao@gmail.com>, Al Viro <viro@zeniv.linux.org.uk>, Johannes Weiner <hannes@cmpxchg.org>, linux-fsdevel <linux-fsdevel@vger.kernel.org>, kernel-team@fb.com, Kishon Vijay Abraham I <kishon@ti.com>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Roman Gushchin <guro@fb.com> Subject: Re: [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU Date: Tue, 10 Mar 2020 10:16:37 +0100 [thread overview] Message-ID: <20200310091637.GC8447@dhcp22.suse.cz> (raw) In-Reply-To: <CAK8P3a1HEhwie1uUObQMJyGcs_WSwz4Gj81tAWXZX4d2ff77XA@mail.gmail.com> I am worried this went quite tangent to the original patch under discussion here, but let me clarify at least one point. On Mon 09-03-20 16:04:54, Arnd Bergmann wrote: > On Mon, Mar 9, 2020 at 3:05 PM Russell King - ARM Linux admin [...] > > What happened to requests for memory from highmem being able to be > > sourced from lowmem if highmem wasn't available? That used to be > > standard kernel behaviour. > > AFAICT this is how it's supposed to work, but for some reason it > doesn't always. I don't know the details, but have heard of recent > complaints about it. I don't think it's the actual get_free_pages > failing, but rather some heuristic looking at the number of free pages. This is indeed the case. There are low memory reserves which are not allowed for requests which can be satisfied from higher zones. This is the case for many many years. Just have a look at lowmem_reserve and their usage in __zone_watermark_ok. The layout of the reserves can be configured by /proc/sys/vm/lowmem_reserve_ratio. HTH -- Michal Hocko SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org> To: Arnd Bergmann <arnd@arndb.de> Cc: Nishanth Menon <nm@ti.com>, Johannes Weiner <hannes@cmpxchg.org>, Rik van Riel <riel@surriel.com>, Catalin Marinas <catalin.marinas@arm.com>, Roman Gushchin <guro@fb.com>, Santosh Shilimkar <santosh.shilimkar@oracle.com>, Dave Chinner <david@fromorbit.com>, Russell King - ARM Linux admin <linux@armlinux.org.uk>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Tero Kristo <t-kristo@ti.com>, Linux-MM <linux-mm@kvack.org>, Yafang Shao <laoar.shao@gmail.com>, Al Viro <viro@zeniv.linux.org.uk>, Santosh Shilimkar <ssantosh@kernel.org>, linux-fsdevel <linux-fsdevel@vger.kernel.org>, kernel-team@fb.com, Kishon Vijay Abraham I <kishon@ti.com>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Linux ARM <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU Date: Tue, 10 Mar 2020 10:16:37 +0100 [thread overview] Message-ID: <20200310091637.GC8447@dhcp22.suse.cz> (raw) In-Reply-To: <CAK8P3a1HEhwie1uUObQMJyGcs_WSwz4Gj81tAWXZX4d2ff77XA@mail.gmail.com> I am worried this went quite tangent to the original patch under discussion here, but let me clarify at least one point. On Mon 09-03-20 16:04:54, Arnd Bergmann wrote: > On Mon, Mar 9, 2020 at 3:05 PM Russell King - ARM Linux admin [...] > > What happened to requests for memory from highmem being able to be > > sourced from lowmem if highmem wasn't available? That used to be > > standard kernel behaviour. > > AFAICT this is how it's supposed to work, but for some reason it > doesn't always. I don't know the details, but have heard of recent > complaints about it. I don't think it's the actual get_free_pages > failing, but rather some heuristic looking at the number of free pages. This is indeed the case. There are low memory reserves which are not allowed for requests which can be satisfied from higher zones. This is the case for many many years. Just have a look at lowmem_reserve and their usage in __zone_watermark_ok. The layout of the reserves can be configured by /proc/sys/vm/lowmem_reserve_ratio. HTH -- Michal Hocko SUSE Labs _______________________________________________ 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:[~2020-03-10 9:16 UTC|newest] Thread overview: 116+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-11 17:55 [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU Johannes Weiner 2020-02-11 18:20 ` Johannes Weiner 2020-02-11 19:05 ` Rik van Riel 2020-02-11 19:05 ` Rik van Riel 2020-02-11 19:31 ` Johannes Weiner 2020-02-11 23:44 ` Andrew Morton 2020-02-12 0:28 ` Linus Torvalds 2020-02-12 0:28 ` Linus Torvalds 2020-02-12 0:47 ` Andrew Morton 2020-02-12 1:03 ` Linus Torvalds 2020-02-12 1:03 ` Linus Torvalds 2020-02-12 1:03 ` Linus Torvalds 2020-02-12 8:50 ` Russell King - ARM Linux admin 2020-02-12 8:50 ` Russell King - ARM Linux admin 2020-02-13 9:50 ` Lucas Stach 2020-02-13 9:50 ` Lucas Stach 2020-02-13 9:50 ` Lucas Stach 2020-02-13 16:52 ` Arnd Bergmann 2020-02-13 16:52 ` Arnd Bergmann 2020-02-13 16:52 ` Arnd Bergmann 2020-02-15 11:25 ` Geert Uytterhoeven 2020-02-15 11:25 ` [cip-dev] " Geert Uytterhoeven 2020-02-15 11:25 ` Geert Uytterhoeven 2020-02-15 11:25 ` Geert Uytterhoeven 2020-02-15 16:59 ` Arnd Bergmann 2020-02-15 16:59 ` [cip-dev] " Arnd Bergmann 2020-02-15 16:59 ` Arnd Bergmann 2020-02-15 16:59 ` Arnd Bergmann 2020-02-16 9:44 ` Geert Uytterhoeven 2020-02-16 9:44 ` [cip-dev] " Geert Uytterhoeven 2020-02-16 9:44 ` Geert Uytterhoeven 2020-02-16 9:44 ` Geert Uytterhoeven 2020-02-16 19:54 ` Chris Paterson 2020-02-16 19:54 ` [cip-dev] " Chris Paterson 2020-02-16 19:54 ` Chris Paterson 2020-02-16 20:38 ` Arnd Bergmann 2020-02-16 20:38 ` [cip-dev] " Arnd Bergmann 2020-02-16 20:38 ` Arnd Bergmann 2020-02-16 20:38 ` Arnd Bergmann 2020-02-20 14:35 ` Chris Paterson 2020-02-20 14:35 ` [cip-dev] " Chris Paterson 2020-02-20 14:35 ` Chris Paterson 2020-02-26 18:04 ` santosh.shilimkar 2020-02-26 18:04 ` santosh.shilimkar 2020-02-26 21:01 ` Arnd Bergmann 2020-02-26 21:01 ` Arnd Bergmann 2020-02-26 21:01 ` Arnd Bergmann 2020-02-26 21:11 ` santosh.shilimkar 2020-02-26 21:11 ` santosh.shilimkar 2020-03-06 20:34 ` Nishanth Menon 2020-03-06 20:34 ` Nishanth Menon 2020-03-07 1:08 ` santosh.shilimkar 2020-03-07 1:08 ` santosh.shilimkar 2020-03-08 10:58 ` Arnd Bergmann 2020-03-08 10:58 ` Arnd Bergmann 2020-03-08 10:58 ` Arnd Bergmann 2020-03-08 14:19 ` Russell King - ARM Linux admin 2020-03-08 14:19 ` Russell King - ARM Linux admin 2020-03-09 13:33 ` Arnd Bergmann 2020-03-09 13:33 ` Arnd Bergmann 2020-03-09 13:33 ` Arnd Bergmann 2020-03-09 14:04 ` Russell King - ARM Linux admin 2020-03-09 14:04 ` Russell King - ARM Linux admin 2020-03-09 15:04 ` Arnd Bergmann 2020-03-09 15:04 ` Arnd Bergmann 2020-03-09 15:04 ` Arnd Bergmann 2020-03-10 9:16 ` Michal Hocko [this message] 2020-03-10 9:16 ` Michal Hocko 2020-03-09 15:59 ` Catalin Marinas 2020-03-09 15:59 ` Catalin Marinas 2020-03-09 16:09 ` Russell King - ARM Linux admin 2020-03-09 16:09 ` Russell King - ARM Linux admin 2020-03-09 16:57 ` Catalin Marinas 2020-03-09 16:57 ` Catalin Marinas 2020-03-09 19:46 ` Arnd Bergmann 2020-03-09 19:46 ` Arnd Bergmann 2020-03-09 19:46 ` Arnd Bergmann 2020-03-11 14:29 ` Catalin Marinas 2020-03-11 14:29 ` Catalin Marinas 2020-03-11 16:59 ` Arnd Bergmann 2020-03-11 16:59 ` Arnd Bergmann 2020-03-11 16:59 ` Arnd Bergmann 2020-03-11 17:26 ` Catalin Marinas 2020-03-11 17:26 ` Catalin Marinas 2020-03-11 22:21 ` Arnd Bergmann 2020-03-11 22:21 ` Arnd Bergmann 2020-03-11 22:21 ` Arnd Bergmann 2020-02-12 3:58 ` Matthew Wilcox 2020-02-12 8:09 ` Michal Hocko 2020-02-17 13:31 ` Pavel Machek 2020-02-12 16:35 ` Johannes Weiner 2020-02-12 18:26 ` Andrew Morton 2020-02-12 18:52 ` Johannes Weiner 2020-02-12 12:25 ` Yafang Shao 2020-02-12 12:25 ` Yafang Shao 2020-02-12 16:42 ` Johannes Weiner 2020-02-13 1:47 ` Yafang Shao 2020-02-13 1:47 ` Yafang Shao 2020-02-13 13:46 ` Johannes Weiner 2020-02-14 2:02 ` Yafang Shao 2020-02-14 2:02 ` Yafang Shao 2020-02-13 18:34 ` [PATCH v2] " Johannes Weiner 2020-02-14 16:53 ` [PATCH] " kbuild test robot 2020-02-14 16:53 ` kbuild test robot 2020-02-14 21:30 ` kbuild test robot 2020-02-14 21:30 ` kbuild test robot 2020-02-14 21:30 ` [PATCH] vfs: fix boolreturn.cocci warnings kbuild test robot 2020-02-14 21:30 ` kbuild test robot 2020-05-12 21:29 ` [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU Johannes Weiner 2020-05-13 1:32 ` Yafang Shao 2020-05-13 1:32 ` Yafang Shao 2020-05-13 13:00 ` Johannes Weiner 2020-05-13 21:15 ` Andrew Morton 2020-05-14 11:27 ` Johannes Weiner 2020-05-14 2:24 ` Andrew Morton 2020-05-14 10:37 ` Johannes Weiner
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