diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/writeback.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 80adf3d88d9d..3148db1296a2 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -7,6 +7,7 @@ #include <linux/sched.h> #include <linux/workqueue.h> #include <linux/fs.h> +#include <linux/flex_proportions.h> DECLARE_PER_CPU(int, dirty_throttle_leaks); @@ -87,6 +88,36 @@ struct writeback_control { }; /* + * A wb_domain represents a domain that wb's (bdi_writeback's) belong to + * and are measured against each other in. There always is one global + * domain, global_wb_domain, that every wb in the system is a member of. + * This allows measuring the relative bandwidth of each wb to distribute + * dirtyable memory accordingly. + */ +struct wb_domain { + /* + * Scale the writeback cache size proportional to the relative + * writeout speed. + * + * We do this by keeping a floating proportion between BDIs, based + * on page writeback completions [end_page_writeback()]. Those + * devices that write out pages fastest will get the larger share, + * while the slower will get a smaller share. + * + * We use page writeout completions because we are interested in + * getting rid of dirty pages. Having them written out is the + * primary goal. + * + * We introduce a concept of time, a period over which we measure + * these events, because demand can/will vary over time. The length + * of this period itself is measured in page writeback completions. + */ + struct fprop_global completions; + struct timer_list period_timer; /* timer for aging of completions */ + unsigned long period_time; +}; + +/* * fs/fs-writeback.c */ struct bdi_writeback; @@ -120,6 +151,7 @@ static inline void laptop_sync_completion(void) { } #endif 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; |