From: Paolo Bonzini <pbonzini@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>, qemu-devel@nongnu.org
Cc: Fam Zheng <fam@euphon.net>, Kevin Wolf <kwolf@redhat.com>,
qemu-block@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: Re: [PATCH 7/7] aio-posix: remove idle poll handlers to improve scalability
Date: Thu, 5 Mar 2020 18:28:29 +0100 [thread overview]
Message-ID: <58ce9251-77ba-9db2-b1c1-fd97cd175e9a@redhat.com> (raw)
In-Reply-To: <20200305170806.1313245-8-stefanha@redhat.com>
On 05/03/20 18:08, Stefan Hajnoczi wrote:
> + /*
> + * List of handlers participating in userspace polling. Accessed almost
> + * exclusively from aio_poll() and therefore not an RCU list. Protected by
> + * ctx->list_lock.
> + */
> + AioHandlerList poll_aio_handlers;
> +
Not sure I understand the "almost" part. If it's accessed only from
aio_poll() it is protected via either AIO_WAIT_WHILE or the BQL, not by
ctx->list_lock; if it's protected by ctx->list_lock (using
qemu_lockcnt_inc in readers), it is an RCU list.
Paolo
next prev parent reply other threads:[~2020-03-05 17:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-05 17:07 [PATCH 0/7] aio-posix: polling scalability improvements Stefan Hajnoczi
2020-03-05 17:08 ` [PATCH 1/7] aio-posix: completely stop polling when disabled Stefan Hajnoczi
2020-03-05 17:08 ` [PATCH 2/7] aio-posix: move RCU_READ_LOCK() into run_poll_handlers() Stefan Hajnoczi
2020-03-05 17:15 ` Paolo Bonzini
2020-03-06 13:43 ` Stefan Hajnoczi
2020-03-05 17:08 ` [PATCH 3/7] aio-posix: extract ppoll(2) and epoll(7) fd monitoring Stefan Hajnoczi
2020-03-05 17:08 ` [PATCH 4/7] aio-posix: simplify FDMonOps->update() prototype Stefan Hajnoczi
2020-03-05 17:08 ` [PATCH 5/7] aio-posix: add io_uring fd monitoring implementation Stefan Hajnoczi
2020-03-05 17:08 ` [PATCH 6/7] aio-posix: support userspace polling of fd monitoring Stefan Hajnoczi
2020-03-05 17:08 ` [PATCH 7/7] aio-posix: remove idle poll handlers to improve scalability Stefan Hajnoczi
2020-03-05 17:28 ` Paolo Bonzini [this message]
2020-03-06 13:50 ` Stefan Hajnoczi
2020-03-06 14:17 ` Paolo Bonzini
2020-03-09 16:37 ` Stefan Hajnoczi
2020-03-09 16:47 ` [PATCH 0/7] aio-posix: polling scalability improvements Stefan Hajnoczi
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