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 02/23] MM: extend block-plugging to cover all swap reads with read-ahead
Date: Sun, 23 Jan 2022 23:27:08 -0800 [thread overview]
Message-ID: <Ye5UzEzvN8WWMNBn@infradead.org> (raw)
In-Reply-To: <164299611274.26253.13900771841681128440.stgit@noble.brown>
On Mon, Jan 24, 2022 at 02:48:32PM +1100, NeilBrown wrote:
> Code that does swap read-ahead uses blk_start_plug() and
> blk_finish_plug() to allow lower levels to combine multiple read-ahead
> pages into a single request, but calls blk_finish_plug() *before*
> submitting the original (non-ahead) read request.
> This missed an opportunity to combine read requests.
>
> This patch moves the blk_finish_plug to *after* all the reads.
> This will likely combine the primary read with some of the "ahead"
> reads, and that may slightly increase the latency of that read, but it
> should more than make up for this by making more efficient use of the
> storage path.
>
> The patch mostly makes the code look more consistent. Performance
> change is unlikely to be noticeable.
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
> Fixes-no-auto-backport: 3fb5c298b04e ("swap: allow swap readahead to be merged")
Is this really a thing?
next prev parent reply other threads:[~2022-01-24 7:27 UTC|newest]
Thread overview: 53+ 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 [this message]
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 8:52 ` Christoph Hellwig
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 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 ` [PATCH 00/23 V3] Repair SWAP-over_NFS Geert Uytterhoeven
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