From: Christoph Hellwig <hch@infradead.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>,
linux-nfs@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/18] Structural cleanup for filesystem-based swap
Date: Tue, 21 Dec 2021 00:34:15 -0800 [thread overview]
Message-ID: <YcGRh+crvndawbT3@infradead.org> (raw)
In-Reply-To: <163969850251.20885.10819272484905153807.stgit@noble.brown>
On Fri, Dec 17, 2021 at 10:48:22AM +1100, NeilBrown wrote:
> Linux primarily uses IO to block devices for swap, but can send the IO
> requests to a filesystem. This has only ever worked for NFS, and that
> hasn't worked for a while due to a lack of testing. This seems like a
> good time for some tidy-up before restoring swap-over-NFS functionality.
The changes look good to me, but I think this needs to be split into
separate, self-contained patches.
>
> This patch:
Patch 1:
> - updates the documentation (both copies!) for swap_activate which
> is woefully out-of-date
Patch 2:
> - drops the call to the filesystem for ->set_page_dirty(). These
> pages do not belong to the filesystem, and it has no interest
> in the dirty status.
Patch 3:
> - move the responsibility for setting SWP_FS_OPS to ->swap_activate()
> and also requires it to always call add_swap_extent(). This makes
> it much easier to find filesystems that require SWP_FS_OPS.
Patch 4:
> - introduces a new address_space operation "swap_rw" for swap IO.
> The code currently used ->readpage for reads and ->direct_IO for
> writes. The former imposes a limit of one-page-at-a-time, the
> later means that direct writes and swap writes are encouraged to
> use the same path. While similar, swap can often be simpler as
> it can assume that no allocation is needed, and coherence with the
> page cache is irrelevant.
next prev parent reply other threads:[~2021-12-21 8:34 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-16 23:48 [PATCH 00/18 V2] Repair SWAP-over-NFS NeilBrown
2021-12-16 23:48 ` [PATCH 01/18] Structural cleanup for filesystem-based swap NeilBrown
2021-12-17 10:33 ` kernel test robot
2021-12-17 10:33 ` kernel test robot
2021-12-21 8:34 ` Christoph Hellwig [this message]
2021-12-16 23:48 ` [PATCH 04/18] MM: perform async writes to SWP_FS_OPS swap-space NeilBrown
2021-12-21 8:41 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 06/18] MM: submit multipage reads for " NeilBrown
2021-12-17 7:09 ` kernel test robot
2021-12-17 7:09 ` kernel test robot
2021-12-21 8:44 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 03/18] MM: use ->swap_rw for reads from " NeilBrown
2021-12-20 12:16 ` Mark Hemment
2021-12-21 8:40 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 02/18] MM: create new mm/swap.h header file NeilBrown
2021-12-17 10:03 ` kernel test robot
2021-12-17 10:03 ` kernel test robot
2021-12-21 8:36 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 05/18] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space NeilBrown
2021-12-17 8:51 ` kernel test robot
2021-12-17 8:51 ` kernel test robot
2021-12-21 8:43 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 16/18] SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC NeilBrown
2021-12-16 23:48 ` [PATCH 10/18] NFS: swap IO handling is slightly different for O_DIRECT IO NeilBrown
2021-12-20 15:02 ` Mark Hemment
2021-12-16 23:48 ` [PATCH 09/18] NFS: rename nfs_direct_IO and use as ->swap_rw NeilBrown
2021-12-16 23:48 ` [PATCH 07/18] MM: submit multipage write for SWP_FS_OPS swap-space NeilBrown
2021-12-20 12:21 ` Mark Hemment
2021-12-16 23:48 ` [PATCH 12/18] SUNRPC/auth: async tasks mustn't block waiting for memory NeilBrown
2021-12-16 23:48 ` [PATCH 15/18] NFS: discard NFS_RPC_SWAPFLAGS and RPC_TASK_ROOTCREDS NeilBrown
2021-12-16 23:48 ` [PATCH 18/18] NFS: swap-out must always use STABLE writes NeilBrown
2021-12-16 23:48 ` [PATCH 08/18] MM: Add AS_CAN_DIO mapping flag NeilBrown
2021-12-19 13:38 ` Mark Hemment
2021-12-19 20:59 ` NeilBrown
2021-12-21 8:46 ` Christoph Hellwig
2022-01-19 3:54 ` NeilBrown
2021-12-16 23:48 ` [PATCH 11/18] SUNRPC/call_alloc: async tasks mustn't block waiting for memory NeilBrown
2021-12-16 23:48 ` [PATCH 17/18] NFSv4: keep state manager thread active if swap is enabled NeilBrown
2021-12-16 23:48 ` [PATCH 14/18] SUNRPC: remove scheduling boost for "SWAPPER" tasks NeilBrown
2021-12-16 23:48 ` [PATCH 13/18] SUNRPC/xprt: async tasks mustn't block waiting for memory NeilBrown
2021-12-17 21:29 ` [PATCH 00/18 V2] Repair SWAP-over-NFS Anna Schumaker
2021-12-19 21:07 ` NeilBrown
2021-12-21 8:48 ` Christoph Hellwig
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