lkml.org 
[lkml]   [2019]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] async: Let kfree() out of the critical area of the lock


On Fri, 11 Oct 2019, Yunfeng Ye wrote:

> The async_lock is big global lock, and kfree() is not always cheap, it
> will increase lock contention. it's better let kfree() outside the lock
> to keep the critical area as short as possible.
>
> Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
> Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> Reviewed-by: Bart Van Assche <bvanassche@acm.org>
> ---
> v1 -> v2:
> - update the description
> - add "Reviewed-by"
>
> 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);

The wakeup should happen before the kfree() for the very same reasons.

Thanks,

tglx

\
 
 \ /
  Last update: 2019-11-15 19:33    [W:0.070 / U:1.384 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site