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Re: [Qemu-devel] [PATCH] file-posix: Cache lseek result for data regions
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] file-posix: Cache lseek result for data regions |
Date: |
Fri, 25 Jan 2019 11:10:56 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 |
On 24/01/19 16:42, Kevin Wolf wrote:
>> Recently Paolo asked me not to add more users of AioContext lock.
>> Unfortunately
>> I don't understand the whole picture around it.. Doesn't this apply here?
>> https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg03410.html
> I don't know. Honestly I feel nobody except Paolo knows, because we
> don't know his patches yet.
This is true. On the other hand, the AioContext lock is only used in
some special cases around block jobs and blk_set_aio_context, and in
general the block devices already should not have any dependencies
(unless they crept in without me noticing).
In particular...
> But raw doesn't have an s->lock yet, so I
> think removing the AioContext lock involves some work on it anyway and
> adding this doesn't really change the amount of work.
... BDRVRawState doesn't have any data that changes after open, does it?
This is why it doesn't have an s->lock.
Paolo
Re: [Qemu-devel] [PATCH] file-posix: Cache lseek result for data regions, Eric Blake, 2019/01/24
Re: [Qemu-devel] [PATCH] file-posix: Cache lseek result for data regions, Vladimir Sementsov-Ogievskiy, 2019/01/24