From: Adam Borowski <kilobyte@angband.pl>
To: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>,
linux-fsdevel@vger.kernel.org, jlayton@kernel.org,
Christoph Hellwig <hch@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
dchinner@redhat.com, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: Could it be made possible to offer "supplementary" data to a DIO write ?
Date: Thu, 5 Aug 2021 19:45:34 +0200 [thread overview]
Message-ID: <YQwjvlvnBNPJbMwc@angband.pl> (raw)
In-Reply-To: <1186271.1628174281@warthog.procyon.org.uk>
On Thu, Aug 05, 2021 at 03:38:01PM +0100, David Howells wrote:
> Generally, I prefer to write back the minimum I can get away with (as does the
> Linux NFS client AFAICT).
>
> However, if everyone agrees that we should only ever write back a multiple of
> a certain block size, even to network filesystems, what block size should that
> be? Note that PAGE_SIZE varies across arches and folios are going to
> exacerbate this. What I don't want to happen is that you read from a file, it
> creates, say, a 4M (or larger) folio; you change three bytes and then you're
> forced to write back the entire 4M folio.
grep . /sys/class/block/*/queue/minimum_io_size
and also hw_sector_size, logical_block_size, physical_block_size.
The data seems suspect to me, though. I get 4096 for a spinner (looks
sane), 512 for nvme (less than page size), and 4096 for pmem (I'd expect
cacheline or ECC block).
Meow!
--
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⢿⡄⠘⠷⠚⠋⠀ Certified airhead; got the CT scan to prove that!
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prev parent reply other threads:[~2021-08-05 18:27 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-05 10:19 Could it be made possible to offer "supplementary" data to a DIO write ? David Howells
2021-08-05 12:37 ` Matthew Wilcox
2021-08-05 13:07 ` David Howells
2021-08-05 13:35 ` Matthew Wilcox
2021-08-05 14:38 ` David Howells
2021-08-05 15:06 ` Matthew Wilcox
2021-08-05 15:38 ` David Howells
2021-08-05 16:35 ` Canvassing for network filesystem write size vs page size David Howells
2021-08-05 17:27 ` Linus Torvalds
2021-08-05 17:43 ` Trond Myklebust
2021-08-05 22:11 ` Matthew Wilcox
2021-08-06 13:42 ` David Howells
2021-08-06 14:17 ` Matthew Wilcox
2021-08-06 15:04 ` David Howells
2021-08-05 17:52 ` Adam Borowski
2021-08-05 18:50 ` Jeff Layton
2021-08-05 23:47 ` Matthew Wilcox
2021-08-06 13:44 ` David Howells
2021-08-05 17:45 ` Adam Borowski [this message]
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