From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
To: Yunfeng Ye <yeyunfeng@huawei.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
bvanassche@acm.org, bhelgaas@google.com, dsterba@suse.com,
"tglx@linutronix.de" <tglx@linutronix.de>,
sakari.ailus@linux.intel.com
Cc: "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: Wed, 25 Sep 2019 08:20:30 -0700 [thread overview]
Message-ID: <f49df2d42d7e97b61a5e26ff4d89ede5fbe37a35.camel@linux.intel.com> (raw)
In-Reply-To: <216356b1-38c1-8477-c4e8-03f497dd6ac8@huawei.com>
On Wed, 2019-09-25 at 20:52 +0800, Yunfeng Ye wrote:
> It's not necessary to put kfree() in the critical area of the lock, so
> let it out.
>
> Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
> ---
> kernel/async.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/async.c b/kernel/async.c
> index 4f9c1d6..1de270d 100644
> --- a/kernel/async.c
> +++ b/kernel/async.c
> @@ -135,12 +135,12 @@ static void async_run_entry_fn(struct work_struct *work)
> list_del_init(&entry->domain_list);
> list_del_init(&entry->global_list);
>
> - /* 3) free the entry */
> - kfree(entry);
> atomic_dec(&entry_count);
> -
> spin_unlock_irqrestore(&async_lock, flags);
>
> + /* 3) free the entry */
> + kfree(entry);
> +
> /* 4) wake up any waiters */
> wake_up(&async_done);
> }
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.
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
next prev parent reply other threads:[~2019-09-25 15:20 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 [this message]
2019-09-26 7:58 ` Yunfeng Ye
2019-09-26 11:06 ` David Sterba
2019-09-26 15:18 ` Bart Van Assche
2019-09-27 1:00 ` Yunfeng Ye
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