Commit 293128b1 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
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dm writecache: have ssd writeback wait if the kcopyd workqueue is busy 



Make dm-writecache wait if the kcopyd workqueue is busy (as will
happen if waiting for page allocation or inside submit_bio).

This change improves performance of "mkfs.ext2" by approximately 20%
on one testbed.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 8c77f1cb

drivers/md/dm-kcopyd.c

+6 −0
Original line number Diff line number Diff line
@@ -980,3 +980,9 @@ void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc) 
	kfree(kc);

}

EXPORT_SYMBOL(dm_kcopyd_client_destroy);



void dm_kcopyd_client_flush(struct dm_kcopyd_client *kc)

{

	flush_workqueue(kc->kcopyd_wq);

}

EXPORT_SYMBOL(dm_kcopyd_client_flush);

drivers/md/dm-writecache.c

+5 −0
Original line number Diff line number Diff line
@@ -1812,6 +1812,11 @@ static void writecache_writeback(struct work_struct *work) 
	struct writeback_list wbl;

	unsigned long n_walked;



	if (!WC_MODE_PMEM(wc)) {

		/* Wait for any active kcopyd work on behalf of ssd writeback */

		dm_kcopyd_client_flush(wc->dm_kcopyd);

	}



	wc_lock(wc);

restart:

	if (writecache_has_error(wc)) {

include/linux/dm-kcopyd.h

+1 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ MODULE_PARM_DESC(name, description) 
struct dm_kcopyd_client;

struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle);

void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);

void dm_kcopyd_client_flush(struct dm_kcopyd_client *kc);



/*

 * Submit a copy job to kcopyd.  This is built on top of the