From: Artem Bityutskiy <dedekind1@gmail.com>
To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Jens Axboe <jens.axboe@oracle.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
chris.mason@oracle.com, david@fromorbit.com, hch@infradead.org,
akpm@linux-foundation.org, jack@suse.cz, richard@rsk.demon.co.uk,
damien.wyart@free.fr, fweisbec@gmail.com, Alan.Brunelle@hp.com
Subject: Re: [PATCH 02/10] writeback: switch to per-bdi threads for flushing data
Date: Wed, 08 Jul 2009 07:47:36 +0300 [thread overview]
Message-ID: <4A5424E8.1070201@gmail.com> (raw)
In-Reply-To: <1247014636.2560.539.camel@ymzhang>
Zhang, Yanmin wrote:
>>> + list_for_each_entry_safe(bdi, tmp, &bdi_list, bdi_list) {
>>> + if (bdi->task || !bdi_has_dirty_io(bdi))
>>> + continue;
>>> +
>>> + bdi_add_default_flusher_task(bdi);
>>> + }
>>> +
>>> + set_current_state(TASK_INTERRUPTIBLE);
>>> +
>> What happens if we are preempted here? Since we have TASK_INTERRUPTIBLE
>> state, we will not come back unless some other task wakes us up. Who
>> would wake us up in this case?
> If it's preempted (CONFIG_PREEMPT=y), it will stay in runqueue. Only when
> it calls schedule initiatively or calls schedule when exiting to user space,
> it will be moved out of runqueue if its state isn't TASK_RUNNING.
>
> See flag PREEMPT_ACTIVE.
OK, thanks for the hint!
--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)
WARNING: multiple messages have this Message-ID (diff)
From: Artem Bityutskiy <dedekind1@gmail.com>
To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Jens Axboe <jens.axboe@oracle.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
chris.mason@oracle.com, david@fromorbit.com, hch@infradead.org,
akpm@linux-foundation.org, jack@suse.cz, richard@rsk.demon.co.uk,
damien.wyart@free.fr, fweisbec@gmail.com, Alan.Brunelle@hp.com
Subject: Re: [PATCH 02/10] writeback: switch to per-bdi threads for flushing data
Date: Wed, 08 Jul 2009 07:47:36 +0300 [thread overview]
Message-ID: <4A5424E8.1070201@gmail.com> (raw)
In-Reply-To: <1247014636.2560.539.camel@ymzhang>
Zhang, Yanmin wrote:
>>> + list_for_each_entry_safe(bdi, tmp, &bdi_list, bdi_list) {
>>> + if (bdi->task || !bdi_has_dirty_io(bdi))
>>> + continue;
>>> +
>>> + bdi_add_default_flusher_task(bdi);
>>> + }
>>> +
>>> + set_current_state(TASK_INTERRUPTIBLE);
>>> +
>> What happens if we are preempted here? Since we have TASK_INTERRUPTIBLE
>> state, we will not come back unless some other task wakes us up. Who
>> would wake us up in this case?
> If it's preempted (CONFIG_PREEMPT=y), it will stay in runqueue. Only when
> it calls schedule initiatively or calls schedule when exiting to user space,
> it will be moved out of runqueue if its state isn't TASK_RUNNING.
>
> See flag PREEMPT_ACTIVE.
OK, thanks for the hint!
--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)
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next prev parent reply other threads:[~2009-07-08 4:48 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-25 10:41 [PATCH 0/10] Per-bdi writeback flusher threads v12 Jens Axboe
2009-06-25 10:41 ` [PATCH 01/10] writeback: move dirty inodes from super_block to backing_dev_info Jens Axboe
2009-06-25 10:41 ` [PATCH 02/10] writeback: switch to per-bdi threads for flushing data Jens Axboe
2009-07-06 12:55 ` Artem Bityutskiy
2009-07-06 12:55 ` Artem Bityutskiy
2009-07-06 13:13 ` Jens Axboe
2009-07-06 13:26 ` Artem Bityutskiy
2009-07-06 13:26 ` Artem Bityutskiy
2009-07-07 15:27 ` Artem Bityutskiy
2009-07-07 15:27 ` Artem Bityutskiy
2009-07-08 0:57 ` Zhang, Yanmin
2009-07-08 4:47 ` Artem Bityutskiy [this message]
2009-07-08 4:47 ` Artem Bityutskiy
2009-06-25 10:41 ` [PATCH 03/10] writeback: get rid of pdflush completely Jens Axboe
2009-06-25 10:41 ` [PATCH 04/10] writeback: separate the flushing state/task from the bdi Jens Axboe
2009-06-25 10:41 ` [PATCH 05/10] writeback: support > 1 flusher thread per bdi Jens Axboe
2009-07-06 12:18 ` Artem Bityutskiy
2009-07-06 12:22 ` Jens Axboe
2009-07-06 13:37 ` Artem Bityutskiy
2009-07-06 13:49 ` Jamie Lokier
2009-07-06 14:11 ` Artem Bityutskiy
2009-07-06 14:11 ` Artem Bityutskiy
2009-07-06 15:43 ` Jens Axboe
2009-06-25 10:41 ` [PATCH 06/10] writeback: allow sleepy exit of default writeback task Jens Axboe
2009-06-25 10:42 ` [PATCH 07/10] writeback: add some debug inode list counters to bdi stats Jens Axboe
2009-06-25 10:42 ` [PATCH 08/10] writeback: add name to backing_dev_info Jens Axboe
2009-06-25 10:42 ` [PATCH 09/10] writeback: check for registered bdi in flusher add and inode dirty Jens Axboe
2009-06-25 10:42 ` [PATCH 10/10] writeback: use spin_trylock() in bdi_writeback_all() for WB_SYNC_NONE Jens Axboe
2009-06-29 8:43 ` [PATCH 0/10] Per-bdi writeback flusher threads v12 Zhang, Yanmin
-- strict thread matches above, loose matches on Subject: below --
2009-08-31 12:14 [PATCH 0/10] Per-bdi writeback flusher threads v14 Jens Axboe
2009-08-31 12:14 ` [PATCH 02/10] writeback: switch to per-bdi threads for flushing data Jens Axboe
2009-08-31 12:58 ` Christoph Hellwig
2009-08-31 17:29 ` Jens Axboe
2009-06-17 11:07 [PATCH 0/10] Per-bdi writeback flusher threads v11 Jens Axboe
2009-06-17 11:07 ` [PATCH 02/10] writeback: switch to per-bdi threads for flushing data Jens Axboe
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