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Commit ce1ccd07 authored by Shaohua Li's avatar Shaohua Li
Browse files

raid5-cache: suspend reclaim thread instead of shutdown 



There is mechanism to suspend a kernel thread. Use it instead of playing
create/destroy game.

Signed-off-by: default avatarShaohua Li <shli@fb.com>
Reviewed-by: default avatarNeilBrown <neilb@suse.de>
Cc: Song Liu <songliubraving@fb.com>
parent 1919cbb2

drivers/md/md.c

+3 −1
Original line number Diff line number Diff line
@@ -7187,10 +7187,12 @@ static int md_thread(void *arg) 
		wait_event_interruptible_timeout

			(thread->wqueue,

			 test_bit(THREAD_WAKEUP, &thread->flags)

			 || kthread_should_stop(),

			 || kthread_should_stop() || kthread_should_park(),

			 thread->timeout);



		clear_bit(THREAD_WAKEUP, &thread->flags);

		if (kthread_should_park())

			kthread_parkme();

		if (!kthread_should_stop())

			thread->run(thread);

	}

drivers/md/raid5-cache.c

+5 −13
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/raid/md_p.h>

#include <linux/crc32c.h>

#include <linux/random.h>

#include <linux/kthread.h>

#include "md.h"

#include "raid5.h"

#include "bitmap.h"
@@ -1437,23 +1438,14 @@ void r5l_quiesce(struct r5l_log *log, int state) 
	struct mddev *mddev;

	if (!log || state == 2)

		return;

	if (state == 0) {

		/*

		 * This is a special case for hotadd. In suspend, the array has

		 * no journal. In resume, journal is initialized as well as the

		 * reclaim thread.

		 */

		if (log->reclaim_thread)

			return;

		log->reclaim_thread = md_register_thread(r5l_reclaim_thread,

					log->rdev->mddev, "reclaim");

		log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;

	} else if (state == 1) {

	if (state == 0)

		kthread_unpark(log->reclaim_thread->tsk);

	else if (state == 1) {

		/* make sure r5l_write_super_and_discard_space exits */

		mddev = log->rdev->mddev;

		wake_up(&mddev->sb_wait);

		kthread_park(log->reclaim_thread->tsk);

		r5l_wake_reclaim(log, MaxSector);

		md_unregister_thread(&log->reclaim_thread);

		r5l_do_reclaim(log);

	}

}