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From: Uday Shankar <ushankar@purestorage.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org
Subject: Re: [PATCH] ublk: decouple hctx and ublk server threads
Date: Wed, 9 Oct 2024 15:11:19 -0600	[thread overview]
Message-ID: <Zwbxd0947cRh7NyY@dev-ushankar.dev.purestorage.com> (raw)
In-Reply-To: <ZwSU1yRc0e6ipehp@fedora>

On Tue, Oct 08, 2024 at 10:11:35AM +0800, Ming Lei wrote:
> Forget to mention, `struct ublk_queue` and `struct ublk_io` are operated
> lockless now, since we suppose both two are read/write in single pthread.
> 
> If we kill this limit, READ/WRITE on the two structures have to
> protected, which may add extra cost, :-(

Argh, yes you're right. Fortunately, ublk_queue looks like it is
read-only in the completion path, so we should be able to get away
without synchronization there. ublk_io will need some synchronization
but with a correctly written ublk server, the synchronization should
almost always be uncontended and therefore, hopefully, unnoticeable.

I'll see what I can come up with in v2.


      reply	other threads:[~2024-10-09 21:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-02 22:44 [PATCH] ublk: decouple hctx and ublk server threads Uday Shankar
2024-10-03 23:40 ` Uday Shankar
2024-10-05 21:24 ` kernel test robot
2024-10-06  9:20 ` Ming Lei
2024-10-07 19:50   ` Uday Shankar
2024-10-08  1:47     ` Ming Lei
2024-10-08  2:11       ` Ming Lei
2024-10-09 21:11         ` Uday Shankar [this message]

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