From: Keith Busch <kbusch@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@infradead.org>,
Keith Busch <kbusch@meta.com>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
axboe@kernel.dk, iommu@lists.linux.dev
Subject: Re: [PATCHv3 1/2] block: accumulate segment page gaps per bio
Date: Tue, 26 Aug 2025 16:33:15 -0600 [thread overview]
Message-ID: <aK42K_-gHrOQsNyv@kbusch-mbp> (raw)
In-Reply-To: <20250826135734.GA4532@lst.de>
On Tue, Aug 26, 2025 at 03:57:34PM +0200, Christoph Hellwig wrote:
> On Tue, Aug 26, 2025 at 07:47:46AM -0600, Keith Busch wrote:
> > Currently, the virtual boundary is always compared to bv_offset, which
> > is a page offset. If the virtual boundary is larger than a page, then we
> > need something like "page_to_phys(bv.bv_page) + bv.bv_offset" every
> > place we need to check against the virt boundary.
>
> bv_offset is only guaranteed to be a page offset if your use
> bio_for_each_segment(_all) or the low-level helpers implementing
> it and not bio_for_each_bvec(_all) where it can be much larger
> than PAGE_SIZE.
Yes, good point. So we'd have a folio offset when it's not a single
page, but I don't think we want to special case large folios for every
virt boundary check. It's looking like replace bvec's "page + offset"
with phys addrs, yeah?!
next prev parent reply other threads:[~2025-08-26 22:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-21 20:44 [PATCHv3 0/2] block+nvme: reducing virtual boundary mask reliance Keith Busch
2025-08-21 20:44 ` [PATCHv3 1/2] block: accumulate segment page gaps per bio Keith Busch
2025-08-25 13:46 ` Christoph Hellwig
2025-08-25 14:10 ` Keith Busch
2025-08-26 13:03 ` Christoph Hellwig
2025-08-26 13:47 ` Keith Busch
2025-08-26 13:57 ` Christoph Hellwig
2025-08-26 22:33 ` Keith Busch [this message]
2025-08-27 7:37 ` Christoph Hellwig
2025-08-30 1:47 ` Keith Busch
2025-09-02 5:36 ` Christoph Hellwig
2025-08-21 20:44 ` [PATCHv3 2/2] nvme: remove virtual boundary for sgl capable devices Keith Busch
2025-08-25 13:49 ` Christoph Hellwig
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