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Re: [Qemu-devel] [PATCH v2 00/11] curl: fix curl read
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v2 00/11] curl: fix curl read |
Date: |
Tue, 14 May 2013 16:50:19 +0800 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Tue, 05/14 10:22, Stefan Hajnoczi wrote:
> On Tue, May 14, 2013 at 10:26:19AM +0800, Fam Zheng wrote:
> > - CURLDataCache holds the user data read from libcurl, it is in a list
> > ordered by access, the used cache is moved to list head on access, so
> > the tail element is freed first. BDRVCURLState.cache_quota is the
> > threshold to start freeing cache.
>
> Can you explain the need for a cache?
>
> The guest kernel already does readahead if it wants to. It can be tuned
> from inside the guest if performance doesn't meet expectations. The
> block/curl.c-specific cache cannot be tuned from the guest.
>
It's prefetch. If we send request for every read request, there'll be
too much overhead for protocal transactions.
I just name it CURLDataCache. Guest may have multiple sequencial reads,
so I used a list of it.
If you think this is reasonable, I'll update the commit messages on this.
--
Fam
- Re: [Qemu-devel] [PATCH v2 04/11] curl: fix curl_open, (continued)
- [Qemu-devel] [PATCH v2 05/11] curl: add timer to BDRVCURLState, Fam Zheng, 2013/05/13
- [Qemu-devel] [PATCH v2 06/11] curl: introduce CURLDataCache, Fam Zheng, 2013/05/13
- [Qemu-devel] [PATCH v2 07/11] curl: make use of CURLDataCache., Fam Zheng, 2013/05/13
- [Qemu-devel] [PATCH v2 08/11] curl: use list to store CURLState, Fam Zheng, 2013/05/13
- [Qemu-devel] [PATCH v2 09/11] curl: release everything on curl_close, Fam Zheng, 2013/05/13
- [Qemu-devel] [PATCH v2 10/11] curl: add cache quota., Fam Zheng, 2013/05/13
- [Qemu-devel] [PATCH v2 11/11] curl: introduce ssl_no_cert runtime option., Fam Zheng, 2013/05/13
- Re: [Qemu-devel] [PATCH v2 00/11] curl: fix curl read, Stefan Hajnoczi, 2013/05/14