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author | Tejun Heo <tj@kernel.org> | 2015-05-23 01:23:22 +0300 |
---|---|---|
committer | Jens Axboe <axboe@fb.com> | 2015-06-02 17:38:12 +0300 |
commit | dcc25ae76eb7b8ff883eaaab57e30e8f2f085be3 (patch) | |
tree | 7fb1d01278ad2b16a1c21ead3e567a3bb7d00c25 /include/linux/writeback.h | |
parent | 380c27ca33ebecc9da35aa90c8b3a9154f90aac2 (diff) | |
download | linux-dcc25ae76eb7b8ff883eaaab57e30e8f2f085be3.tar.xz |
writeback: move global_dirty_limit into wb_domain
This patch is a part of the series to define wb_domain which
represents a domain that wb's (bdi_writeback's) belong to and are
measured against each other in. This will enable IO backpressure
propagation for cgroup writeback.
global_dirty_limit exists to regulate the global dirty threshold which
is a property of the wb_domain. This patch moves hard_dirty_limit,
dirty_lock, and update_time into wb_domain.
This is pure reorganization and doesn't introduce any behavioral
changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include/linux/writeback.h')
-rw-r--r-- | include/linux/writeback.h | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 3148db1296a2..5fdd4e1805e6 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -95,6 +95,8 @@ struct writeback_control { * dirtyable memory accordingly. */ struct wb_domain { + spinlock_t lock; + /* * Scale the writeback cache size proportional to the relative * writeout speed. @@ -115,6 +117,19 @@ struct wb_domain { struct fprop_global completions; struct timer_list period_timer; /* timer for aging of completions */ unsigned long period_time; + + /* + * The dirtyable memory and dirty threshold could be suddenly + * knocked down by a large amount (eg. on the startup of KVM in a + * swapless system). This may throw the system into deep dirty + * exceeded state and throttle heavy/light dirtiers alike. To + * retain good responsiveness, maintain global_dirty_limit for + * tracking slowly down to the knocked down dirty threshold. + * + * Both fields are protected by ->lock. + */ + unsigned long dirty_limit_tstamp; + unsigned long dirty_limit; }; /* @@ -153,7 +168,7 @@ void throttle_vm_writeout(gfp_t gfp_mask); bool zone_dirty_ok(struct zone *zone); int wb_domain_init(struct wb_domain *dom, gfp_t gfp); -extern unsigned long global_dirty_limit; +extern struct wb_domain global_wb_domain; /* These are exported to sysctl. */ extern int dirty_background_ratio; |