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Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bd
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll |
Date: |
Thu, 30 Jul 2015 09:35:37 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Wed, 07/29 14:03, Paolo Bonzini wrote:
>
>
> On 29/07/2015 13:53, Fam Zheng wrote:
> >> > Yes, though I think you'd end up reverting patches 10 and 11 in the end.
> > We will add outer disable/enable pairs to prevent another threads's aio_poll
> > from sneaking in between bdrv_aio_poll calls, but we needn't obsolete
> > bdrv_aio_poll() because of that - it can be useful by itself. For example
> > bdrv_aio_cancel shouldn't look at ioeventfd, otherwise it could spin for too
> > long on high load. Does that make sense?
>
> Did you mean bdrv_drain() (when it is not already surrounded by
> disable/enable pairs in the caller)? But yes, that makes sense.
>
> I'm not sure that it makes sense to disable/enable in places such as
> bdrv_pread. The caller's block, if any, should suffice. In this sense
> you'd end up reverting large parts of patch 10.
>
> Then you would have to see how many calls to bdrv_aio_poll are still
> there, and how many can be converted with no semantic change to aio_poll
> (e.g. there's no difference in qemu-img.c), and you'd end up reverting
> patches 9 and 11 too. But we can look at that later.
>
Okay.
There 19 bdrv_aio_poll()'s after this series:
block.c bdrv_create
block/curl.c curl_init_state
block/io.c bdrv_drain
block/io.c bdrv_drain_all
block/io.c bdrv_prwv_co
block/io.c bdrv_get_block_status_above
block/io.c bdrv_aio_cancel
block/io.c bdrv_flush
block/io.c bdrv_discard
block/io.c bdrv_flush_io_queue
block/nfs.c nfs_get_allocated_file_size
block/qed-table.c qed_read_l1_table_sync
block/qed-table.c qed_write_l1_table_sync
block/qed-table.c qed_read_l2_table_sync
block/qed-table.c qed_write_l2_table_sync
blockjob.c block_job_finish_sync
include/block/block.h bdrv_get_stats
qemu-img.c run_block_job
qemu-io-cmds.c do_co_write_zeroes
qemu-io-cmds.c wait_break_f
Most of them make some sense to me, but not many make a real difference. The
most important ones should be bdrv_drain* and bdrv_flush, and can be taken care
of from caller side.
Fam
- [Qemu-devel] [PATCH v2 08/11] aio-win32: Implement aio_{disable, enable}_clients, (continued)
- [Qemu-devel] [PATCH v2 08/11] aio-win32: Implement aio_{disable, enable}_clients, Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 09/11] block: Introduce bdrv_aio_poll, Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 10/11] block: Replace nested aio_poll with bdrv_aio_poll, Fam Zheng, 2015/07/29
- [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/29
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll,
Fam Zheng <=
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/07/30
Re: [Qemu-devel] [PATCH v2 00/11] aio: Introduce handler type to fix nested aio_poll for dataplane, Paolo Bonzini, 2015/07/29