From: Paolo Bonzini <pbonzini@redhat.com>
To: Harsh Bora <harsh@linux.vnet.ibm.com>
Cc: qemu-devel@nongnu.org, aneesh.kumar@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] [PATCH 2/2] 9p-synth: use mutex on read-side
Date: Sat, 18 Aug 2012 20:46:47 +0200 [thread overview]
Message-ID: <502FE317.3020607@redhat.com> (raw)
In-Reply-To: <502951BC.1090400@linux.vnet.ibm.com>
Il 13/08/2012 21:13, Harsh Bora ha scritto:
>>
>
> Hi Paolo,
>
> The rcu_read_[un]lock() macros were added as no-ops (based on your
> inputs on #qemu) to replace reader-writer locks with RCU based locking
> as suggested while proposing QemuRWLock API for RW locks (See
> http://lists.gnu.org/archive/html/qemu-devel/2011-10/msg00192.html).
The rwlock was also premature optimization IMHO.
> v9fs_synth_mutex was actually a pthread_rwlock_t earlier.
> I am not sure if reader lock would be better than having a plain mutex
> for readers as well.
>
> Aneesh, inputs ?
>
> Also, if we are going forward with this change, we may also want to
> remove definition of QLIST_INSERT_HEAD_RCU, since the code being remove
> below is the only consumer of that macro.
It's in a library file, so I don't mind leaving it in. I think liu ping
fan's patches were using it.
Paolo
prev parent reply other threads:[~2012-08-18 18:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-08 11:55 [Qemu-devel] [PATCH 0/2] 9p-synth: remove poor-man RCU Paolo Bonzini
2012-08-08 11:55 ` [Qemu-devel] [PATCH 1/2] 9p-synth: fix read-side critical sections Paolo Bonzini
2012-08-13 18:47 ` Harsh Bora
2012-08-08 11:55 ` [Qemu-devel] [PATCH 2/2] 9p-synth: use mutex on read-side Paolo Bonzini
2012-08-13 19:13 ` Harsh Bora
2012-08-18 18:46 ` Paolo Bonzini [this message]
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=502FE317.3020607@redhat.com \
--to=pbonzini@redhat.com \
--cc=aneesh.kumar@linux.vnet.ibm.com \
--cc=harsh@linux.vnet.ibm.com \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.