From: Matthew Wilcox <willy@infradead.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
leon@kernel.org, hch@lst.de, kbusch@kernel.org, sagi@grimberg.me,
axboe@kernel.dk, joro@8bytes.org, brauner@kernel.org,
hare@suse.de, david@fromorbit.com, djwong@kernel.org,
john.g.garry@oracle.com, ritesh.list@gmail.com,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-mm@kvack.org, gost.dev@samsung.com, p.raghav@samsung.com,
da.gomez@samsung.com, kernel@pankajraghav.com
Subject: Re: [RFC 2/4] blkdev: lift BLK_MAX_BLOCK_SIZE to page cache limit
Date: Thu, 20 Mar 2025 16:06:45 +0000 [thread overview]
Message-ID: <Z9w9FWG2hKCe7mhR@casper.infradead.org> (raw)
In-Reply-To: <5459e3e0-656c-4d94-82c7-3880608f9ac8@acm.org>
On Thu, Mar 20, 2025 at 09:01:46AM -0700, Bart Van Assche wrote:
> On 3/20/25 4:13 AM, Luis Chamberlain wrote:
> > -/*
> > - * We should strive for 1 << (PAGE_SHIFT + MAX_PAGECACHE_ORDER)
> > - * however we constrain this to what we can validate and test.
> > - */
> > -#define BLK_MAX_BLOCK_SIZE SZ_64K
> > +#define BLK_MAX_BLOCK_SIZE 1 << (PAGE_SHIFT + MAX_PAGECACHE_ORDER)
> > /* blk_validate_limits() validates bsize, so drivers don't usually need to */
> > static inline int blk_validate_block_size(unsigned long bsize)
>
> All logical block sizes above 4 KiB trigger write amplification if there
> are applications that write 4 KiB at a time, isn't it? Isn't that issue
> even worse for logical block sizes above 64 KiB?
I think everybody knows this Bart. You've raised it before, we've
talked about it, and you're not bringing anything new to the discussion
this time. Why bring it up again?
next prev parent reply other threads:[~2025-03-20 16:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-20 11:13 [RFC 0/4] nvme-pci: breaking the 512 KiB max IO boundary Luis Chamberlain
2025-03-20 11:13 ` [RFC 1/4] iomap: use BLK_MAX_BLOCK_SIZE for the iomap zero page Luis Chamberlain
2025-03-20 11:13 ` [RFC 2/4] blkdev: lift BLK_MAX_BLOCK_SIZE to page cache limit Luis Chamberlain
2025-03-20 16:01 ` Bart Van Assche
2025-03-20 16:06 ` Matthew Wilcox [this message]
2025-03-20 16:15 ` Bart Van Assche
2025-03-20 16:27 ` Matthew Wilcox
2025-03-20 16:34 ` Bart Van Assche
2025-03-20 16:44 ` Christoph Hellwig
2025-03-24 10:58 ` Bart Van Assche
2025-03-24 15:02 ` Matthew Wilcox
2025-03-20 11:13 ` [RFC 3/4] nvme-pci: bump segments to what the device can use Luis Chamberlain
2025-03-20 11:13 ` [RFC 4/4] nvme-pci: add quirk for qemu with bogus NOWS Luis Chamberlain
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