From: Namjae Jeon <linkinjeon@gmail.com>
To: Rabin Vincent <rabin@rab.in>
Cc: fengguang.wu@intel.com, axboe@kernel.dk,
linux-kernel@vger.kernel.org, chanho0207@gmail.com
Subject: Re: [PATCHv2] backing-dev: fix wakeup timer races with bdi_unregister()
Date: Sat, 21 Jan 2012 00:04:23 +0900 [thread overview]
Message-ID: <CAKYAXd-OzSsNgTakm_6Dq4p5C4KViBH6ctdXDO7tfkn=XrE8xA@mail.gmail.com> (raw)
In-Reply-To: <20120120120801.GA22145@debian>
>
> After this patch, this is what wakeup_timer_fn looks like:
>
> static void wakeup_timer_fn(unsigned long data)
> {
> struct backing_dev_info *bdi = (struct backing_dev_info *)data;
>
> spin_lock_bh(&bdi->wb_lock);
> if (bdi->wb.task) {
> trace_writeback_wake_thread(bdi);
> wake_up_process(bdi->wb.task);
> } else if (bdi->dev) {
> /*
> * When bdi tasks are inactive for long time, they are killed.
> * In this case we have to wake-up the forker thread which
> * should create and run the bdi thread.
> */
> trace_writeback_wake_forker_thread(bdi);
> wake_up_process(default_backing_dev_info.wb.task);
> }
> spin_unlock_bh(&bdi->wb_lock);
> }
>
> So how will trace_writeback_wake_forker_thread() be called if bdi->dev is NULL?
>
> This patch added the if (bdi->dev) check, perhaps you overlooked that?
Hi Rabin.
I clearly understand. Thanks for your explanation.
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
next prev parent reply other threads:[~2012-01-20 15:04 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-05 8:49 [PATCH] mm/backing-dev.c: fix crash when USB/SCSI device is detached Chanho Min
2012-01-15 10:28 ` Rabin Vincent
2012-01-15 12:58 ` Wu Fengguang
2012-01-15 15:41 ` Rabin Vincent
2012-01-16 2:53 ` Wu Fengguang
2012-01-16 5:28 ` Chanho Min
2012-01-16 5:50 ` Wu Fengguang
2012-01-16 5:53 ` Wu Fengguang
2012-01-16 6:34 ` Chanho Min
2012-01-18 19:43 ` Rabin Vincent
2012-01-19 16:50 ` [PATCHv2] backing-dev: fix wakeup timer races with bdi_unregister() Rabin Vincent
2012-01-19 23:46 ` Namjae Jeon
2012-01-20 5:24 ` Rabin Vincent
2012-01-20 6:15 ` Namjae Jeon
2012-01-20 10:03 ` Rabin Vincent
2012-01-20 11:18 ` Namjae Jeon
2012-01-20 12:08 ` Rabin Vincent
2012-01-20 15:04 ` Namjae Jeon [this message]
2012-01-31 13:24 ` Wu Fengguang
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