From: Al Viro <viro@zeniv.linux.org.uk>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>,
Matthew Wilcox <willy@infradead.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [RFC] what to do with IOCB_DSYNC?
Date: Mon, 23 May 2022 00:42:33 +0000 [thread overview]
Message-ID: <YorYeQpW9nBJEeSx@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <1b2cb369-2247-8c10-bd6e-405a8167f795@kernel.dk>
On Sun, May 22, 2022 at 02:03:35PM -0600, Jens Axboe wrote:
> Right, I'm saying it's not _immediately_ clear which cases are what when
> reading the code.
>
> > up a while ago. And no, turning that into indirect calls ended up with
> > arseloads of overhead, more's the pity...
>
> It's a shame, since indirect calls make for nicer code, but it's always
> been slower and these days even more so.
>
> > Anyway, at the moment I have something that builds; hadn't tried to
> > boot it yet.
>
> Nice!
Boots and survives LTP and xfstests... Current variant is in vfs.git#work.iov_iter
(head should be at 27fa77a9829c). I have *not* looked into the code generation
in primitives; the likely/unlikely on those cascades of ifs need rethinking.
I hadn't added ITER_KBUF (or KADDR, whatever); should be an easy incremental,
though.
At the moment it's carved up into 6 commits:
btrfs_direct_write(): cleaner way to handle generic_write_sync() suppression
struct file: use anonymous union member for rcuhead and llist
iocb: delay evaluation of IS_SYNC(...) until we want to check IOCB_DSYNC
keep iocb_flags() result cached in struct file
new iov_iter flavour - ITER_UBUF
switch new_sync_{read,write}() to ITER_UBUF
Review and testing would be welcome, but it's obviously not this window fodder.
next prev parent reply other threads:[~2022-05-23 0:42 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-21 0:46 [RFC] what to do with IOCB_DSYNC? Al Viro
2021-06-21 13:59 ` Christoph Hellwig
2021-06-21 14:03 ` Matthew Wilcox
2021-06-21 14:09 ` Christoph Hellwig
2021-06-21 14:16 ` Matthew Wilcox
2021-06-21 14:22 ` Christoph Hellwig
2021-06-21 14:32 ` Al Viro
2021-06-21 14:35 ` Christoph Hellwig
2021-06-21 15:22 ` Jens Axboe
2022-05-21 17:48 ` Al Viro
2022-05-21 19:03 ` Jens Axboe
2022-05-21 22:14 ` Jens Axboe
2022-05-22 7:45 ` Christoph Hellwig
2022-05-22 10:23 ` Matthew Wilcox
2022-05-22 10:36 ` Al Viro
2022-05-22 11:15 ` Matthew Wilcox
2022-05-22 11:45 ` Christoph Hellwig
2022-05-22 12:39 ` Jens Axboe
2022-05-22 12:48 ` Al Viro
2022-05-22 13:02 ` Jens Axboe
2022-05-22 13:07 ` Al Viro
2022-05-22 13:09 ` Jens Axboe
2022-05-22 18:06 ` Jens Axboe
2022-05-22 18:25 ` Al Viro
2022-05-22 18:29 ` Jens Axboe
2022-05-22 18:39 ` Al Viro
2022-05-22 18:48 ` Jens Axboe
2022-05-22 19:04 ` Al Viro
2022-05-22 20:03 ` Jens Axboe
2022-05-23 0:42 ` Al Viro [this message]
2022-05-23 1:22 ` Jens Axboe
2022-05-23 1:28 ` Jens Axboe
2022-05-23 1:50 ` Jens Axboe
2022-05-23 2:43 ` Jens Axboe
2022-05-23 14:22 ` Al Viro
2022-05-23 14:34 ` Jens Axboe
2022-05-23 14:47 ` Al Viro
2022-05-23 15:12 ` Jens Axboe
2022-05-23 15:44 ` Jens Axboe
2022-05-23 15:49 ` Matthew Wilcox
2022-05-23 15:55 ` Jens Axboe
2022-05-23 16:03 ` Jens Axboe
2022-05-26 14:46 ` Jason A. Donenfeld
2022-05-27 10:09 ` Ingo Molnar
2022-05-27 10:15 ` Jason A. Donenfeld
2022-05-27 14:45 ` Samuel Neves
2022-05-27 10:25 ` Ingo Molnar
2022-05-27 10:36 ` Borislav Petkov
2022-05-28 20:54 ` Sedat Dilek
2022-05-28 20:38 ` Sedat Dilek
2022-05-28 20:39 ` Sedat Dilek
2022-05-23 16:15 ` Al Viro
2022-05-25 14:34 ` Matthew Wilcox
2022-05-26 23:19 ` Al Viro
2022-05-27 14:51 ` Jens Axboe
2022-05-22 12:21 ` Al Viro
2022-05-22 7:43 ` Christoph Hellwig
2022-05-22 12:41 ` Al Viro
2022-05-22 12:51 ` Christoph Hellwig
2021-06-21 14:22 ` Al Viro
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