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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: NeilBrown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	Chuck Lever <chuck.lever@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mel Gorman <mgorman@suse.de>,
	Christoph Hellwig <hch@infradead.org>,
	David Howells <dhowells@redhat.com>,
	"open list:NFS, SUNRPC, AND..." <linux-nfs@vger.kernel.org>,
	Linux MM <linux-mm@kvack.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 00/23 V3] Repair SWAP-over_NFS
Date: Mon, 7 Feb 2022 18:55:48 +0100	[thread overview]
Message-ID: <CAMuHMdXw6bhOf8BMWzje1h_gaBg8TxZXWAQgL0cpdYBkZ+LwXw@mail.gmail.com> (raw)
In-Reply-To: <164299573337.26253.7538614611220034049.stgit@noble.brown>

Hi Neil,

On Mon, Jan 24, 2022 at 5:40 PM NeilBrown <neilb@suse.de> wrote:
> swap-over-NFS currently has a variety of problems.
>
> swap writes call generic_write_checks(), which always fails on a swap
> file, so it completely fails.
> Even without this, various deadlocks are possible - largely due to
> improvements in NFS memory allocation (using NOFS instead of ATOMIC)
> which weren't tested against swap-out.
>
> NFS is the only filesystem that has supported fs-based swap IO, and it
> hasn't worked for several releases, so now is a convenient time to clean
> up the swap-via-filesystem interfaces - we cannot break anything !
>
> So the first few patches here clean up and improve various parts of the
> swap-via-filesystem code.  ->activate_swap() is given a cleaner
> interface, a new ->swap_rw is introduced instead of burdening
> ->direct_IO, etc.
>
> Current swap-to-filesystem code only ever submits single-page reads and
> writes.  These patches change that to allow multi-page IO when adjacent
> requests are submitted.  Writes are also changed to be async rather than
> sync.  This substantially speeds up write throughput for swap-over-NFS.
>
> Some of the NFS patches can land independently of the MM patches.  A few
> require the MM patches to land first.

Thanks for your series!
Swap over NFS was indeed broken last time I tried[1], but with your
series, it's working again on arm32 (RZ/A1 with 32 MiB of RAM, 100Mbps
Ethernet and Debian 9 nfsroot). My system was exercised using "apt
update", and the subsequent "apt upgrade" is still running, though
(it took more than 6 hours to build the apt dependency tree, now it's
trying hard to create a list of packages...).

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

BTW, I think you do want to run scripts/checkpatch.pl on your series,
and improve it by fixing a few of the reported warnings (function
definition arguments should also have an identifier name, missing
data_race() comment, missing SPDX-License-Identifier tag).

[1] https://lore.kernel.org/all/20191230153238.29878-1-geert+renesas@glider.be/

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

      parent reply	other threads:[~2022-02-07 18:02 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-24  3:48 [PATCH 00/23 V3] Repair SWAP-over_NFS NeilBrown
2022-01-24  3:48 ` [PATCH 05/23] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space NeilBrown
2022-01-24  7:31   ` Christoph Hellwig
2022-01-24  3:48 ` [PATCH 03/23] MM: drop swap_set_page_dirty NeilBrown
2022-01-24  7:28   ` Christoph Hellwig
2022-01-24  3:48 ` [PATCH 14/23] NFS: swap IO handling is slightly different for O_DIRECT IO NeilBrown
2022-01-24  8:58   ` Christoph Hellwig
2022-01-24 13:22   ` Mark Hemment
2022-01-26 22:51     ` NeilBrown
2022-01-24  3:48 ` [PATCH 22/23] NFS: swap-out must always use STABLE writes NeilBrown
2022-01-26  3:45   ` Trond Myklebust
2022-01-26 21:42     ` NeilBrown
2022-01-24  3:48 ` [PATCH 23/23] SUNRPC: lock against ->sock changing during sysfs read NeilBrown
2022-01-24  3:48 ` [PATCH 08/23] DOC: update documentation for swap_activate and swap_rw NeilBrown
2022-01-24  8:50   ` Christoph Hellwig
2022-01-24  3:48 ` [PATCH 07/23] MM: perform async writes to SWP_FS_OPS swap-space using ->swap_rw NeilBrown
2022-01-24  8:49   ` Christoph Hellwig
2022-01-24  3:48 ` [PATCH 02/23] MM: extend block-plugging to cover all swap reads with read-ahead NeilBrown
2022-01-24  7:27   ` Christoph Hellwig
2022-01-26 21:47     ` NeilBrown
2022-01-26 23:09       ` Hugh Dickins
2022-01-27  0:32         ` NeilBrown
2022-01-24  3:48 ` [PATCH 16/23] SUNRPC/auth: async tasks mustn't block waiting for memory NeilBrown
2022-01-24  3:48 ` [PATCH 04/23] MM: move responsibility for setting SWP_FS_OPS to ->swap_activate NeilBrown
2022-01-24  7:30   ` Christoph Hellwig
2022-01-24  3:48 ` [PATCH 06/23] MM: introduce ->swap_rw and use it for reads from SWP_FS_OPS swap-space NeilBrown
2022-01-24  8:48   ` Christoph Hellwig
2022-01-24  3:48 ` [PATCH 15/23] SUNRPC/call_alloc: async tasks mustn't block waiting for memory NeilBrown
2022-01-24  3:48 ` [PATCH 20/23] SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC NeilBrown
2022-01-24  3:48 ` [PATCH 01/23] MM: create new mm/swap.h header file NeilBrown
2022-02-07 13:51   ` Geert Uytterhoeven
2022-01-24  3:48 ` [PATCH 09/23] MM: submit multipage reads for SWP_FS_OPS swap-space NeilBrown
2022-01-24  8:25   ` kernel test robot
2022-01-24  8:25     ` kernel test robot
2022-01-24  8:52   ` Christoph Hellwig
2022-01-24  9:27   ` kernel test robot
2022-01-24  9:27     ` kernel test robot
2022-01-24 13:16   ` Mark Hemment
2022-01-26 22:04     ` NeilBrown
2022-02-08 11:07   ` Geert Uytterhoeven
2022-01-24  3:48 ` [PATCH 12/23] NFS: remove IS_SWAPFILE hack NeilBrown
2022-01-24  8:56   ` Christoph Hellwig
2022-01-24  3:48 ` [PATCH 19/23] NFS: discard NFS_RPC_SWAPFLAGS and RPC_TASK_ROOTCREDS NeilBrown
2022-01-24  3:48 ` [PATCH 17/23] SUNRPC/xprt: async tasks mustn't block waiting for memory NeilBrown
2022-01-24  3:48 ` [PATCH 18/23] SUNRPC: remove scheduling boost for "SWAPPER" tasks NeilBrown
2022-01-24  3:48 ` [PATCH 21/23] NFSv4: keep state manager thread active if swap is enabled NeilBrown
2022-01-24  3:48 ` [PATCH 11/23] VFS: Add FMODE_CAN_ODIRECT file flag NeilBrown
2022-01-24  8:56   ` Christoph Hellwig
2022-01-26 22:14     ` NeilBrown
2022-01-24  3:48 ` [PATCH 10/23] MM: submit multipage write for SWP_FS_OPS swap-space NeilBrown
2022-01-24  8:55   ` Christoph Hellwig
2022-01-24 10:29   ` kernel test robot
2022-01-24 10:29     ` kernel test robot
2022-01-24  3:48 ` [PATCH 13/23] NFS: rename nfs_direct_IO and use as ->swap_rw NeilBrown
2022-01-24  8:57   ` Christoph Hellwig
2022-02-07 17:55 ` Geert Uytterhoeven [this message]

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