From: Christoph Hellwig <hch@infradead.org>
To: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC] zram: sleepable async read bio completion
Date: Wed, 4 Mar 2026 06:43:48 -0800 [thread overview]
Message-ID: <aahFJM-8VhAjq_IT@infradead.org> (raw)
In-Reply-To: <brqb2utojkegjv3vz542y6fz5pnkxngknaofz6ll4tviy5ljpx@fjvdjtr3tzfv>
On Wed, Mar 04, 2026 at 02:15:03PM +0900, Sergey Senozhatsky wrote:
> that async read back is not trivial anymore - zram needs to decompress
> the page upon bio completion. The problem is that bio completion is
> called from atomic context, while zram decompression is sleepable.
> So at this point we have to deffer the decompression to a workqueue,
> which adds (painful) latency to the read path. We clearly would like
> to avoid that workquque offloading. What can we do about it?
Nothing. bi_end_io is called from hard/softirq context usually.
prev parent reply other threads:[~2026-03-04 14:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-04 5:15 [RFC] zram: sleepable async read bio completion Sergey Senozhatsky
2026-03-04 14:43 ` Christoph Hellwig [this message]
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