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authorColy Li <colyli@suse.de>2018-02-07 11:41:44 -0800
committerJens Axboe <axboe@kernel.dk>2018-02-07 12:50:01 -0700
commit7a5e3ecbe5b7b58e9a78a3738b28244982822e1c (patch)
tree0376b27b78359dde3640a013a269966c184ee5a6 /drivers
parent682811b3ce1a5a4e20d700939a9042f01dbc66c4 (diff)
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: Coly Li <colyli@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Michael Lyle <mlyle@lyle.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/bcache/sysfs.c4
-rw-r--r--drivers/md/bcache/writeback.c2
-rw-r--r--drivers/md/bcache/writeback.h3
3 files changed, 7 insertions, 2 deletions
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index c524305cc9a7..4a6a697e1680 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -218,7 +218,9 @@ STORE(__cached_dev)
sysfs_strtoul_clamp(writeback_rate,
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_nonzero(writeback_rate_p_term_inverse);
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 58218f7e77c3..f1d2fc15abcc 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -655,7 +655,7 @@ void bch_cached_dev_writeback_init(struct cached_dev *dc)
dc->writeback_rate.rate = 1024;
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_i_term_inverse = 10000;
diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h
index 66f1c527fa24..587b25599856 100644
--- a/drivers/md/bcache/writeback.h
+++ b/drivers/md/bcache/writeback.h
@@ -8,6 +8,9 @@
#define MAX_WRITEBACKS_IN_PASS 5
#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
* should be a reasonable fraction of the share, and not to blow up

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