From: Paolo Bonzini <pbonzini@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Anthony Liguori <aliguori@us.ibm.com>,
Ping Fan Liu <pingfank@linux.vnet.ibm.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [RFC 08/13] block: drop bdrv_get_aio_context()
Date: Fri, 14 Jun 2013 10:12:00 -0400 [thread overview]
Message-ID: <51BB24B0.9070503@redhat.com> (raw)
In-Reply-To: <1371203313-26490-9-git-send-email-stefanha@redhat.com>
Il 14/06/2013 05:48, Stefan Hajnoczi ha scritto:
> Associating a BlockDriverState with a single AioContext is not flexible
> enough. Once we make BlockDriverState thread-safe, it will be possible
> to call bdrv_*() functions from multiple event loops.
I'm afraid that this is trading some pain now (converting
qemu_bh_new/qemu_set_fd_handler to aio_bh_new/aio_set_fd_handler) for
more pain later (having to make BDS thread-safe). There aren't that
many (~40) in block layer code.
Making BlockDriverState thread-safe is hard, it is much simpler to run
all the BlockDriverState code in the AioContext thread itself.
There are some things that cannot (basically monitor commands and other
places that are currently using bdrv_drain_all) but they can simply take
a "big AioContext lock".
Paolo
next prev parent reply other threads:[~2013-06-14 14:12 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-14 9:48 [Qemu-devel] [RFC 00/13] dataplane: use block layer Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 01/13] block: fix bdrv_flush() ordering in bdrv_close() Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 02/13] dataplane: sync virtio.c and vring.c virtqueue state Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 03/13] block: add BlockDevOps->drain_threads_cb() Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 04/13] virtio-blk: implement BlockDevOps->drain_threads_cb() Stefan Hajnoczi
2013-06-14 14:23 ` Paolo Bonzini
2013-06-14 9:48 ` [Qemu-devel] [RFC 05/13] exec: do not use qemu/tls.h Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 06/13] qemu-thread: add TLS wrappers Stefan Hajnoczi
2013-06-20 7:26 ` Fam Zheng
2013-06-20 8:50 ` Paolo Bonzini
2013-06-20 12:54 ` Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 07/13] block: add thread_aio_context TLS variable Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 08/13] block: drop bdrv_get_aio_context() Stefan Hajnoczi
2013-06-14 14:12 ` Paolo Bonzini [this message]
2013-06-17 14:57 ` Stefan Hajnoczi
2013-06-17 15:03 ` Paolo Bonzini
2013-06-18 9:29 ` Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 09/13] main-loop: use thread-local AioContext Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 10/13] block: disable I/O throttling outside main loop Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 11/13] dataplane: use block layer for I/O Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 12/13] dataplane: drop ioq Linux AIO request queue Stefan Hajnoczi
2013-06-14 9:48 ` [Qemu-devel] [RFC 13/13] block: drop raw_get_aio_fd() Stefan Hajnoczi
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