From: Stefan Hajnoczi <stefanha@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Fam Zheng" <fam@euphon.net>, "Kevin Wolf" <kwolf@redhat.com>,
qemu-block@nongnu.org, "Stefan Hajnoczi" <stefanha@gmail.com>,
qemu-devel@nongnu.org, "Max Reitz" <mreitz@redhat.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>
Subject: Re: [PATCH 5/5] aio-posix: make AioHandler dispatch O(1) with epoll
Date: Fri, 21 Feb 2020 14:44:34 +0000 [thread overview]
Message-ID: <20200221144434.GC1501077@stefanha-x1.localdomain> (raw)
In-Reply-To: <425318ef-0b19-983b-b2ea-93754c48cb8d@redhat.com>
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On Fri, Feb 21, 2020 at 02:06:26PM +0100, Paolo Bonzini wrote:
> On 21/02/20 13:59, Stefan Hajnoczi wrote:
> > 1. It doesn't crash if the node is currently not on a list.
> > 2. It clears the node's linked list pointers so that future linked
> > list operations (like QLIST_SAFE_REMOVE()) aren't accidentally
> > performed on stale pointers.
> >
> > The node has a long lifespan and will be inserted into ready_lists
> > multiple times. We need to safely remove it from ready_list to protect
> > against a corruption the next time the node is inserted into a
> > ready_list again:
>
> Ah, so the one I singled out is for (2) (we know the node is currently
> on a list), while the one below is for (1). Would it make sense to move
> (2) to Q*_REMOVE_*? We can do it separately after this pull request.
Extending all Q*_REMOVE*() macros to clear the linked list pointers is
nice. I'll send a follow-up patch.
Stefan
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next prev parent reply other threads:[~2020-02-21 14:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-14 17:17 [PATCH 0/5] aio-posix: towards an O(1) event loop Stefan Hajnoczi
2020-02-14 17:17 ` [PATCH 1/5] aio-posix: fix use after leaving scope in aio_poll() Stefan Hajnoczi
2020-02-19 7:02 ` Sergio Lopez
2020-02-14 17:17 ` [PATCH 2/5] aio-posix: don't pass ns timeout to epoll_wait() Stefan Hajnoczi
2020-02-19 10:12 ` Sergio Lopez
2020-02-14 17:17 ` [PATCH 3/5] qemu/queue.h: add QLIST_SAFE_REMOVE() Stefan Hajnoczi
2020-02-19 10:30 ` Sergio Lopez
2020-02-14 17:17 ` [PATCH 4/5] aio-posix: make AioHandler deletion O(1) Stefan Hajnoczi
2020-02-19 10:41 ` Sergio Lopez
2020-02-14 17:17 ` [PATCH 5/5] aio-posix: make AioHandler dispatch O(1) with epoll Stefan Hajnoczi
2020-02-19 11:00 ` Sergio Lopez
2020-02-19 11:13 ` Paolo Bonzini
2020-02-21 12:59 ` Stefan Hajnoczi
2020-02-21 13:06 ` Paolo Bonzini
2020-02-21 14:44 ` Stefan Hajnoczi [this message]
2020-02-21 14:47 ` Stefan Hajnoczi
2020-02-21 15:04 ` Paolo Bonzini
2020-02-21 15:29 ` Stefan Hajnoczi
2020-02-21 15:37 ` Paolo Bonzini
2020-02-21 15:29 ` [PATCH 0/5] aio-posix: towards an O(1) event loop Stefan Hajnoczi
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