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Re: [Qemu-devel] [Qemu-block] [PATCH v3 00/13] main-loop: Get rid of fd_
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [Qemu-block] [PATCH v3 00/13] main-loop: Get rid of fd_read_poll and qemu_set_fd_handler2 |
Date: |
Wed, 20 May 2015 12:35:02 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Tue, 05/19 16:02, Stefan Hajnoczi wrote:
> On Tue, May 19, 2015 at 10:50:57AM +0000, Fam Zheng wrote:
> > v3: Replace previous 13 with a simple return type conversion patch.
> > Drop RFC.
> >
> > This carries out the mandate in the comment of qemu_set_fd_handler2 and
> > removes
> > fd_read_poll from the code base, because it will make the work easier to
> > convert ppoll to epoll in main loop. Also, the aio interface doesn't have a
> > read poll callback, which means this conversion woule be necessary if we
> > want
> > to move iohandler fds from main loop to AioContext.
> >
> > There are five users of the read poll callback now: qemu-nbd, l2tpv3,
> > netmap,
> > socket and tap, which are all covered.
> >
> > Patch 1 adds a stub for qemu_set_fd_handler which will be referenced in
> > coming
> > patches.
> >
> > Patch 2 converts qemu-nbd which compares two global numbers in the
> > fd_read_poll
> > callback.
> >
> > Patches 3~6 converts the four net devices, all of which checks
> > qemu_can_send_packet() in the callback.
> >
> > Patch 7 and 8 finally removes the function.
> >
> > The rest patches are cleanup for the unuseful return value of
> > qemu_set_fd_handler.
> >
> > Please review!
>
> I looked at the first few patches.
>
> The qemu-nbd.c conversion is good. It finds locations where read_poll
> state transitions happen and updates file descriptor monitoring there.
Paolo, will you apply the qemu-nbd.c patch? I'll split net patches into a
separate series.
>
> The l2tpv3 and netmap conversion throws away read_poll and introduces
> problems instead.
>
> Please look at the patches again and either:
>
> 1. Convert everything like you converted qemu-nbd.c. This is a
> conservative approach and we can be confident that behavior is
> unchanged.
OK, I'll try this.
Fam
>
> 2. Convert more carefully, making sure that packets are actually
> dropped and QEMU does not spin on a readable fd.
>
> I prefer #1 because it's easier to check that behavior is still correct.
> It also minimizes queuing inside QEMU.
>
> Stefan
- [Qemu-devel] [PATCH v3 05/13] net/socket: Drop net_socket_can_send, (continued)
- [Qemu-devel] [PATCH v3 05/13] net/socket: Drop net_socket_can_send, Fam Zheng, 2015/05/18
- [Qemu-devel] [PATCH v3 09/13] alsaaudio: Remove unused error handling of qemu_set_fd_handler, Fam Zheng, 2015/05/18
- [Qemu-devel] [PATCH v3 10/13] oss: Remove unused error handling of qemu_set_fd_handler, Fam Zheng, 2015/05/18
- [Qemu-devel] [PATCH v3 06/13] tap: Drop tap_can_send, Fam Zheng, 2015/05/18
- [Qemu-devel] [PATCH v3 11/13] xen_backend: Remove unused error handling of qemu_set_fd_handler, Fam Zheng, 2015/05/18
- [Qemu-devel] [PATCH v3 12/13] event-notifier: Always return 0 for posix implementation, Fam Zheng, 2015/05/18
- [Qemu-devel] [PATCH v3 13/13] iohandler: Change return type of qemu_set_fd_handler to "void", Fam Zheng, 2015/05/18
- [Qemu-devel] [PATCH v3 08/13] main-loop: Drop qemu_set_fd_handler2, Fam Zheng, 2015/05/18
- [Qemu-devel] [PATCH v3 07/13] Change qemu_set_fd_handler2(..., NULL, ...) to qemu_set_fd_handler, Fam Zheng, 2015/05/18
- Re: [Qemu-devel] [Qemu-block] [PATCH v3 00/13] main-loop: Get rid of fd_read_poll and qemu_set_fd_handler2, Stefan Hajnoczi, 2015/05/19