From: Alexander Graf <agraf@suse.de>
To: Max Reitz <mreitz@redhat.com>, qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, Alberto Garcia <berto@igalia.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 1/3] qcow2: Set MIN_L2_CACHE_SIZE to 2
Date: Mon, 01 Jun 2015 18:12:48 +0200 [thread overview]
Message-ID: <556C8480.3060907@suse.de> (raw)
In-Reply-To: <1433174959-7176-2-git-send-email-mreitz@redhat.com>
On 01.06.15 18:09, Max Reitz wrote:
> The L2 cache must cover at least two L2 tables, because during COW two
> L2 tables are accessed simultaneously.
>
> Reported-by: Alexander Graf <agraf@suse.de>
> Cc: qemu-stable <qemu-stable@nongnu.org>
> Signed-off-by: Max Reitz <mreitz@redhat.com>
Tested-by: Alexander Graf <agraf@suse.de>
Alex
> ---
> block/qcow2.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 0076512..aa20022 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -62,7 +62,8 @@
> #define MIN_CLUSTER_BITS 9
> #define MAX_CLUSTER_BITS 21
>
> -#define MIN_L2_CACHE_SIZE 1 /* cluster */
> +/* Must be at least 2 to cover COW */
> +#define MIN_L2_CACHE_SIZE 2 /* clusters */
>
> /* Must be at least 4 to cover all cases of refcount table growth */
> #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
>
next prev parent reply other threads:[~2015-06-01 16:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-01 16:09 [Qemu-devel] [PATCH 0/3] qcow2: Fix MIN_L2_CACHE_SIZE Max Reitz
2015-06-01 16:09 ` [Qemu-devel] [PATCH 1/3] qcow2: Set MIN_L2_CACHE_SIZE to 2 Max Reitz
2015-06-01 16:10 ` Max Reitz
2015-06-01 16:12 ` Alexander Graf [this message]
2015-06-01 16:14 ` Alberto Garcia
2015-06-01 16:09 ` [Qemu-devel] [PATCH 2/3] iotests: qcow2 COW with minimal L2 cache size Max Reitz
2015-06-01 17:01 ` Alberto Garcia
2015-06-01 16:09 ` [Qemu-devel] [PATCH 3/3] qcow2: Add DEFAULT_L2_CACHE_CLUSTERS Max Reitz
2015-06-01 17:16 ` Alberto Garcia
2015-06-02 9:31 ` [Qemu-devel] [PATCH 0/3] qcow2: Fix MIN_L2_CACHE_SIZE Kevin Wolf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=556C8480.3060907@suse.de \
--to=agraf@suse.de \
--cc=berto@igalia.com \
--cc=kwolf@redhat.com \
--cc=mreitz@redhat.com \
--cc=qemu-block@nongnu.org \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).