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Commit 7a5e3ecb authored by Coly Li's avatar Coly Li Committed by Jens Axboe
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bcache: set writeback_rate_update_seconds in range [1, 60] seconds 



dc->writeback_rate_update_seconds can be set via sysfs and its value can
be set to [1, ULONG_MAX].  It does not make sense to set such a large
value, 60 seconds is long enough value considering the default 5 seconds
works well for long time.

Because dc->writeback_rate_update is a special delayed work, it re-arms
itself inside the delayed work routine update_writeback_rate(). When
stopping it by cancel_delayed_work_sync(), there should be a timeout to
wait and make sure the re-armed delayed work is stopped too. A small max
value of dc->writeback_rate_update_seconds is also helpful to decide a
reasonable small timeout.

This patch limits sysfs interface to set dc->writeback_rate_update_seconds
in range of [1, 60] seconds, and replaces the hand-coded number by macros.

Changelog:
v2: fix a rebase typo in v4, which is pointed out by Michael Lyle.
v1: initial version.

Signed-off-by: default avatarColy Li <colyli@suse.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Reviewed-by: default avatarMichael Lyle <mlyle@lyle.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 682811b3

drivers/md/bcache/sysfs.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -218,7 +218,9 @@ STORE(__cached_dev) 
	sysfs_strtoul_clamp(writeback_rate,

	sysfs_strtoul_clamp(writeback_rate,

			    dc->writeback_rate.rate, 1, INT_MAX);

			    dc->writeback_rate.rate, 1, INT_MAX);





	d_strtoul_nonzero(writeback_rate_update_seconds);

	sysfs_strtoul_clamp(writeback_rate_update_seconds,

			    dc->writeback_rate_update_seconds,

			    1, WRITEBACK_RATE_UPDATE_SECS_MAX);

	d_strtoul(writeback_rate_i_term_inverse);

	d_strtoul(writeback_rate_i_term_inverse);

	d_strtoul_nonzero(writeback_rate_p_term_inverse);

	d_strtoul_nonzero(writeback_rate_p_term_inverse);

drivers/md/bcache/writeback.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -655,7 +655,7 @@ void bch_cached_dev_writeback_init(struct cached_dev *dc) 
	dc->writeback_rate.rate		= 1024;

	dc->writeback_rate.rate		= 1024;

	dc->writeback_rate_minimum	= 8;

	dc->writeback_rate_minimum	= 8;





	dc->writeback_rate_update_seconds = 5;

	dc->writeback_rate_update_seconds = WRITEBACK_RATE_UPDATE_SECS_DEFAULT;

	dc->writeback_rate_p_term_inverse = 40;

	dc->writeback_rate_p_term_inverse = 40;

	dc->writeback_rate_i_term_inverse = 10000;

	dc->writeback_rate_i_term_inverse = 10000;

drivers/md/bcache/writeback.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -8,6 +8,9 @@ 
#define MAX_WRITEBACKS_IN_PASS  5

#define MAX_WRITEBACKS_IN_PASS  5

#define MAX_WRITESIZE_IN_PASS   5000	/* *512b */

#define MAX_WRITESIZE_IN_PASS   5000	/* *512b */





#define WRITEBACK_RATE_UPDATE_SECS_MAX		60

#define WRITEBACK_RATE_UPDATE_SECS_DEFAULT	5



/*

/*

 * 14 (16384ths) is chosen here as something that each backing device

 * 14 (16384ths) is chosen here as something that each backing device

 * should be a reasonable fraction of the share, and not to blow up

 * should be a reasonable fraction of the share, and not to blow up