From: David Sterba <dsterba@suse.cz>
To: Yunfeng Ye <yeyunfeng@huawei.com>
Cc: bvanassche@acm.org, bhelgaas@google.com,
"tglx@linutronix.de" <tglx@linutronix.de>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
sakari.ailus@linux.intel.com,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
David Sterba <dsterba@suse.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] async: Let kfree() out of the critical area of the lock
Date: Thu, 26 Sep 2019 13:06:48 +0200 [thread overview]
Message-ID: <20190926110648.GM2751@suse.cz> (raw)
In-Reply-To: <e59af8ae-bacb-2e7e-dd53-ea283960d40e@huawei.com>
On Thu, Sep 26, 2019 at 03:58:36PM +0800, Yunfeng Ye wrote:
> On 2019/9/25 23:20, Alexander Duyck wrote:
> > On Wed, 2019-09-25 at 20:52 +0800, Yunfeng Ye wrote:
> > It probably wouldn't hurt to update the patch description to mention that
> > async_schedule_node_domain does the allocation outside of the lock, then
> > takes the lock and does the list addition and entry_count increment inside
> > the critical section so this is just updating the code to match that it
> > seems.
> >
> > Otherwise the change itself looks safe to me, though I am not sure there
> > is a performance gain to be had so this is mostly just a cosmetic patch.
> >
> The async_lock is big global lock, I think it's good to put kfree() outside
> to keep the critical area as short as possible.
Agreed, kfree is not always cheap. We had patches in btrfs moving kfree
out of critical section(s) after causing softlockups due to increased lock
contention.
next prev parent reply other threads:[~2019-09-26 11:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 12:52 [PATCH] async: Let kfree() out of the critical area of the lock Yunfeng Ye
2019-09-25 13:38 ` gregkh
2019-09-25 13:45 ` Yunfeng Ye
2019-09-25 15:20 ` Alexander Duyck
2019-09-26 7:58 ` Yunfeng Ye
2019-09-26 11:06 ` David Sterba [this message]
2019-09-26 15:18 ` Bart Van Assche
2019-09-27 1:00 ` Yunfeng Ye
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=20190926110648.GM2751@suse.cz \
--to=dsterba@suse.cz \
--cc=alexander.h.duyck@linux.intel.com \
--cc=bhelgaas@google.com \
--cc=bvanassche@acm.org \
--cc=dsterba@suse.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=sakari.ailus@linux.intel.com \
--cc=tglx@linutronix.de \
--cc=yeyunfeng@huawei.com \
/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