From: Christoph Hellwig <hch@infradead.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
netdev@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH] mm: Decline to manipulate the refcount on a slab page
Date: Tue, 11 Mar 2025 22:47:27 -0700 [thread overview]
Message-ID: <Z9Ef75c1ffTWGU_c@infradead.org> (raw)
In-Reply-To: <20250311111511.2531b260@kernel.org>
On Tue, Mar 11, 2025 at 11:15:11AM +0100, Jakub Kicinski wrote:
> On Mon, 10 Mar 2025 14:35:24 +0000 Matthew Wilcox (Oracle) wrote:
> > Long-term, networking needs to stop taking a refcount on the pages that
> > it uses and rely on the caller to hold whatever references are necessary
> > to make the memory stable.
>
> TBH I'm not clear on who is going to fix this.
> IIRC we already told NVMe people that sending slab memory over sendpage
> is not well supported. Plus the bug is in BPF integration, judging by
> the stack traces (skmsg is a BPF thing). Joy.
slab over sendpage doesn't work because you refuse to take the patches
to make it work by transparently falling back to sendmsg. It's a giant
pain for all network storage drivers caused by the networking
maintainers. The ultimate root cause is the fact that networking messes
with the refcounts.
next prev parent reply other threads:[~2025-03-12 5:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-10 14:35 Matthew Wilcox (Oracle)
2025-03-10 14:37 ` Vlastimil Babka
2025-03-10 14:50 ` Matthew Wilcox
2025-03-11 10:15 ` Jakub Kicinski
2025-03-11 15:46 ` Hannes Reinecke
2025-03-11 16:59 ` Matthew Wilcox
2025-03-12 5:48 ` Christoph Hellwig
2025-03-13 7:22 ` Hannes Reinecke
2025-03-13 7:36 ` Christoph Hellwig
2025-03-13 8:34 ` Hannes Reinecke
2025-03-13 8:44 ` Christoph Hellwig
2025-03-13 8:52 ` Hannes Reinecke
2025-03-13 9:15 ` Christoph Hellwig
2025-03-12 5:47 ` Christoph Hellwig [this message]
[not found] <20250310142750.1209192-1-willy@infradead.org>
[not found] ` <77fa8d7e-4752-4979-affe-aa45c8d7795a@suse.de>
[not found] ` <Z88vUFweLyk5s8UD@casper.infradead.org>
2025-03-11 7:05 ` Hannes Reinecke
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