From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>, 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>,
Michal Hocko <mhocko@suse.com>, Rik van Riel <riel@surriel.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: Mon, 9 Mar 2020 16:09:19 +0000 [thread overview]
Message-ID: <20200309160919.GM25745@shell.armlinux.org.uk> (raw)
In-Reply-To: <20200309155945.GA4124965@arrakis.emea.arm.com>
On Mon, Mar 09, 2020 at 03:59:45PM +0000, Catalin Marinas wrote:
> On Sun, Mar 08, 2020 at 11:58:52AM +0100, Arnd Bergmann wrote:
> > - revisit CONFIG_VMSPLIT_4G_4G for arm32 (and maybe mips32)
> > to see if it can be done, and what the overhead is. This is probably
> > more work than the others combined, but also the most promising
> > as it allows the most user address space and physical ram to be used.
>
> A rough outline of such support (and likely to miss some corner cases):
>
> 1. Kernel runs with its own ASID and non-global page tables.
>
> 2. Trampoline code on exception entry/exit to handle the TTBR0 switching
> between user and kernel.
>
> 3. uaccess routines need to be reworked to pin the user pages in memory
> (get_user_pages()) and access them via the kernel address space.
>
> Point 3 is probably the ugliest and it would introduce a noticeable
> slowdown in certain syscalls.
We also need to consider that it has implications for the single-kernel
support; a kernel doing this kind of switching would likely be horrid
for a kernel supporting v6+ with VIPT aliasing caches. Would we be
adding a new red line between kernels supporting VIPT-aliasing caches
(present in earlier v6 implementations) and kernels using this system?
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up
next prev parent reply other threads:[~2020-03-09 16:10 UTC|newest]
Thread overview: 58+ 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 19:31 ` Johannes Weiner
2020-02-11 23:44 ` Andrew Morton
2020-02-12 0:28 ` Linus Torvalds
2020-02-12 0:47 ` Andrew Morton
2020-02-12 1:03 ` Linus Torvalds
2020-02-12 8:50 ` Russell King - ARM Linux admin
2020-02-13 9:50 ` Lucas Stach
2020-02-13 16:52 ` Arnd Bergmann
2020-02-15 11:25 ` Geert Uytterhoeven
2020-02-15 16:59 ` Arnd Bergmann
2020-02-16 9:44 ` Geert Uytterhoeven
2020-02-16 19:54 ` Chris Paterson
2020-02-16 20:38 ` Arnd Bergmann
2020-02-20 14:35 ` Chris Paterson
2020-02-26 18:04 ` santosh.shilimkar
2020-02-26 21:01 ` Arnd Bergmann
2020-02-26 21:11 ` santosh.shilimkar
2020-03-06 20:34 ` Nishanth Menon
2020-03-07 1:08 ` santosh.shilimkar
2020-03-08 10:58 ` Arnd Bergmann
2020-03-08 14:19 ` Russell King - ARM Linux admin
2020-03-09 13:33 ` Arnd Bergmann
2020-03-09 14:04 ` Russell King - ARM Linux admin
2020-03-09 15:04 ` Arnd Bergmann
2020-03-10 9:16 ` Michal Hocko
2020-03-09 15:59 ` Catalin Marinas
2020-03-09 16:09 ` Russell King - ARM Linux admin [this message]
2020-03-09 16:57 ` Catalin Marinas
2020-03-09 19:46 ` Arnd Bergmann
2020-03-11 14:29 ` Catalin Marinas
2020-03-11 16:59 ` Arnd Bergmann
2020-03-11 17:26 ` Catalin Marinas
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 16:42 ` Johannes Weiner
2020-02-13 1:47 ` Yafang Shao
2020-02-13 13:46 ` Johannes Weiner
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 21:30 ` kbuild test robot
2020-02-14 21:30 ` [PATCH] vfs: fix boolreturn.cocci warnings 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 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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