Re: [PATCH 4/9] writeback: track if we're sleeping on progress in balance_dirty_pages()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed 30-03-16 09:07:52, Jens Axboe wrote:
> Note in the bdi_writeback structure if a task is currently being
> limited in balance_dirty_pages(), waiting for writeback to
> proceed.
...
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 11ff8f758631..15e696bc5d14 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -1746,7 +1746,9 @@ pause:
>  					  pause,
>  					  start_time);
>  		__set_current_state(TASK_KILLABLE);
> +		wb->dirty_sleeping = 1;
>  		io_schedule_timeout(pause);
> +		wb->dirty_sleeping = 0;

Huh, but wb->dirty_sleeping is shared by all the processes in the system.
So this is seriously racy, isn't it? You rather need a counter for this to
work.

								Honza
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux