| Message ID | 1432329245-5844-36-git-send-email-tj@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri 22-05-15 17:13:49, Tejun Heo wrote: > bdi->min/max_ratio are user-configurable per-bdi knobs which regulate > dirty limit of each bdi. For cgroup writeback, they need to be > further distributed across wb's (bdi_writeback's) belonging to the > configured bdi. > > This patch introduces wb_min_max_ratio() which distributes > bdi->min/max_ratio according to a wb's proportion in the total active > bandwidth of its bdi. > > v2: Update wb_min_max_ratio() to fix a bug where both min and max were > assigned the min value and avoid calculations when possible. > > Signed-off-by: Tejun Heo <tj@kernel.org> > Cc: Jens Axboe <axboe@kernel.dk> > Cc: Jan Kara <jack@suse.cz> Looks good. You can add: Reviewed-by: Jan Kara <jack@suse.com> Honza > --- > mm/page-writeback.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 46 insertions(+), 4 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index 99b8846..9b55f12 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -155,6 +155,46 @@ static unsigned long writeout_period_time = 0; > */ > #define VM_COMPLETIONS_PERIOD_LEN (3*HZ) > > +#ifdef CONFIG_CGROUP_WRITEBACK > + > +static void wb_min_max_ratio(struct bdi_writeback *wb, > + unsigned long *minp, unsigned long *maxp) > +{ > + unsigned long this_bw = wb->avg_write_bandwidth; > + unsigned long tot_bw = atomic_long_read(&wb->bdi->tot_write_bandwidth); > + unsigned long long min = wb->bdi->min_ratio; > + unsigned long long max = wb->bdi->max_ratio; > + > + /* > + * @wb may already be clean by the time control reaches here and > + * the total may not include its bw. > + */ > + if (this_bw < tot_bw) { > + if (min) { > + min *= this_bw; > + do_div(min, tot_bw); > + } > + if (max < 100) { > + max *= this_bw; > + do_div(max, tot_bw); > + } > + } > + > + *minp = min; > + *maxp = max; > +} > + > +#else /* CONFIG_CGROUP_WRITEBACK */ > + > +static void wb_min_max_ratio(struct bdi_writeback *wb, > + unsigned long *minp, unsigned long *maxp) > +{ > + *minp = wb->bdi->min_ratio; > + *maxp = wb->bdi->max_ratio; > +} > + > +#endif /* CONFIG_CGROUP_WRITEBACK */ > + > /* > * In a memory zone, there is a certain amount of pages we consider > * available for the page cache, which is essentially the number of > @@ -539,9 +579,9 @@ static unsigned long hard_dirty_limit(unsigned long thresh) > */ > unsigned long wb_dirty_limit(struct bdi_writeback *wb, unsigned long dirty) > { > - struct backing_dev_info *bdi = wb->bdi; > u64 wb_dirty; > long numerator, denominator; > + unsigned long wb_min_ratio, wb_max_ratio; > > /* > * Calculate this BDI's share of the dirty ratio. > @@ -552,9 +592,11 @@ unsigned long wb_dirty_limit(struct bdi_writeback *wb, unsigned long dirty) > wb_dirty *= numerator; > do_div(wb_dirty, denominator); > > - wb_dirty += (dirty * bdi->min_ratio) / 100; > - if (wb_dirty > (dirty * bdi->max_ratio) / 100) > - wb_dirty = dirty * bdi->max_ratio / 100; > + wb_min_max_ratio(wb, &wb_min_ratio, &wb_max_ratio); > + > + wb_dirty += (dirty * wb_min_ratio) / 100; > + if (wb_dirty > (dirty * wb_max_ratio) / 100) > + wb_dirty = dirty * wb_max_ratio / 100; > > return wb_dirty; > } > -- > 2.4.0 >
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 99b8846..9b55f12 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -155,6 +155,46 @@ static unsigned long writeout_period_time = 0; */ #define VM_COMPLETIONS_PERIOD_LEN (3*HZ) +#ifdef CONFIG_CGROUP_WRITEBACK + +static void wb_min_max_ratio(struct bdi_writeback *wb, + unsigned long *minp, unsigned long *maxp) +{ + unsigned long this_bw = wb->avg_write_bandwidth; + unsigned long tot_bw = atomic_long_read(&wb->bdi->tot_write_bandwidth); + unsigned long long min = wb->bdi->min_ratio; + unsigned long long max = wb->bdi->max_ratio; + + /* + * @wb may already be clean by the time control reaches here and + * the total may not include its bw. + */ + if (this_bw < tot_bw) { + if (min) { + min *= this_bw; + do_div(min, tot_bw); + } + if (max < 100) { + max *= this_bw; + do_div(max, tot_bw); + } + } + + *minp = min; + *maxp = max; +} + +#else /* CONFIG_CGROUP_WRITEBACK */ + +static void wb_min_max_ratio(struct bdi_writeback *wb, + unsigned long *minp, unsigned long *maxp) +{ + *minp = wb->bdi->min_ratio; + *maxp = wb->bdi->max_ratio; +} + +#endif /* CONFIG_CGROUP_WRITEBACK */ + /* * In a memory zone, there is a certain amount of pages we consider * available for the page cache, which is essentially the number of @@ -539,9 +579,9 @@ static unsigned long hard_dirty_limit(unsigned long thresh) */ unsigned long wb_dirty_limit(struct bdi_writeback *wb, unsigned long dirty) { - struct backing_dev_info *bdi = wb->bdi; u64 wb_dirty; long numerator, denominator; + unsigned long wb_min_ratio, wb_max_ratio; /* * Calculate this BDI's share of the dirty ratio. @@ -552,9 +592,11 @@ unsigned long wb_dirty_limit(struct bdi_writeback *wb, unsigned long dirty) wb_dirty *= numerator; do_div(wb_dirty, denominator); - wb_dirty += (dirty * bdi->min_ratio) / 100; - if (wb_dirty > (dirty * bdi->max_ratio) / 100) - wb_dirty = dirty * bdi->max_ratio / 100; + wb_min_max_ratio(wb, &wb_min_ratio, &wb_max_ratio); + + wb_dirty += (dirty * wb_min_ratio) / 100; + if (wb_dirty > (dirty * wb_max_ratio) / 100) + wb_dirty = dirty * wb_max_ratio / 100; return wb_dirty; }
bdi->min/max_ratio are user-configurable per-bdi knobs which regulate dirty limit of each bdi. For cgroup writeback, they need to be further distributed across wb's (bdi_writeback's) belonging to the configured bdi. This patch introduces wb_min_max_ratio() which distributes bdi->min/max_ratio according to a wb's proportion in the total active bandwidth of its bdi. v2: Update wb_min_max_ratio() to fix a bug where both min and max were assigned the min value and avoid calculations when possible. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> --- mm/page-writeback.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 46 insertions(+), 4 deletions(-)