| Message ID | 20240425131724.36778-2-shikemeng@huaweicloud.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix and cleanups to page-writeback | expand |
On Thu 25-04-24 21:17:21, Kemeng Shi wrote: > Originally, __wb_calc_thresh always calculate wb's share of dirty > throttling threshold. By getting thresh of wb_domain from caller, > __wb_calc_thresh could be used for both dirty throttling and dirty > background threshold. > > This is a preparation to correct threshold calculation of wb in cgroup. > > Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > mm/page-writeback.c | 33 ++++++++++++++++++--------------- > 1 file changed, 18 insertions(+), 15 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index db5769cb12fd..2a3b68aae336 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -838,13 +838,15 @@ static void mdtc_calc_avail(struct dirty_throttle_control *mdtc, > } > > /** > - * __wb_calc_thresh - @wb's share of dirty throttling threshold > + * __wb_calc_thresh - @wb's share of dirty threshold > * @dtc: dirty_throttle_context of interest > + * @thresh: dirty throttling or dirty background threshold of wb_domain in @dtc > * > - * Note that balance_dirty_pages() will only seriously take it as a hard limit > - * when sleeping max_pause per page is not enough to keep the dirty pages under > - * control. For example, when the device is completely stalled due to some error > - * conditions, or when there are 1000 dd tasks writing to a slow 10MB/s USB key. > + * Note that balance_dirty_pages() will only seriously take dirty throttling > + * threshold as a hard limit when sleeping max_pause per page is not enough > + * to keep the dirty pages under control. For example, when the device is > + * completely stalled due to some error conditions, or when there are 1000 > + * dd tasks writing to a slow 10MB/s USB key. > * In the other normal situations, it acts more gently by throttling the tasks > * more (rather than completely block them) when the wb dirty pages go high. > * > @@ -855,19 +857,20 @@ static void mdtc_calc_avail(struct dirty_throttle_control *mdtc, > * The wb's share of dirty limit will be adapting to its throughput and > * bounded by the bdi->min_ratio and/or bdi->max_ratio parameters, if set. > * > - * Return: @wb's dirty limit in pages. The term "dirty" in the context of > - * dirty balancing includes all PG_dirty and PG_writeback pages. > + * Return: @wb's dirty limit in pages. For dirty throttling limit, the term > + * "dirty" in the context of dirty balancing includes all PG_dirty and > + * PG_writeback pages. > */ > -static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc) > +static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc, > + unsigned long thresh) > { > struct wb_domain *dom = dtc_dom(dtc); > - unsigned long thresh = dtc->thresh; > u64 wb_thresh; > unsigned long numerator, denominator; > unsigned long wb_min_ratio, wb_max_ratio; > > /* > - * Calculate this BDI's share of the thresh ratio. > + * Calculate this wb's share of the thresh ratio. > */ > fprop_fraction_percpu(&dom->completions, dtc->wb_completions, > &numerator, &denominator); > @@ -887,9 +890,9 @@ static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc) > > unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh) > { > - struct dirty_throttle_control gdtc = { GDTC_INIT(wb), > - .thresh = thresh }; > - return __wb_calc_thresh(&gdtc); > + struct dirty_throttle_control gdtc = { GDTC_INIT(wb) }; > + > + return __wb_calc_thresh(&gdtc, thresh); > } > > unsigned long cgwb_calc_thresh(struct bdi_writeback *wb) > @@ -908,7 +911,7 @@ unsigned long cgwb_calc_thresh(struct bdi_writeback *wb) > mdtc_calc_avail(&mdtc, filepages, headroom); > domain_dirty_limits(&mdtc); > > - return __wb_calc_thresh(&mdtc); > + return __wb_calc_thresh(&mdtc, mdtc.thresh); > } > > /* > @@ -1655,7 +1658,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc) > * wb_position_ratio() will let the dirtier task progress > * at some rate <= (write_bw / 2) for bringing down wb_dirty. > */ > - dtc->wb_thresh = __wb_calc_thresh(dtc); > + dtc->wb_thresh = __wb_calc_thresh(dtc, dtc->thresh); > dtc->wb_bg_thresh = dtc->thresh ? > div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0; > > -- > 2.30.0 >
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index db5769cb12fd..2a3b68aae336 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -838,13 +838,15 @@ static void mdtc_calc_avail(struct dirty_throttle_control *mdtc, } /** - * __wb_calc_thresh - @wb's share of dirty throttling threshold + * __wb_calc_thresh - @wb's share of dirty threshold * @dtc: dirty_throttle_context of interest + * @thresh: dirty throttling or dirty background threshold of wb_domain in @dtc * - * Note that balance_dirty_pages() will only seriously take it as a hard limit - * when sleeping max_pause per page is not enough to keep the dirty pages under - * control. For example, when the device is completely stalled due to some error - * conditions, or when there are 1000 dd tasks writing to a slow 10MB/s USB key. + * Note that balance_dirty_pages() will only seriously take dirty throttling + * threshold as a hard limit when sleeping max_pause per page is not enough + * to keep the dirty pages under control. For example, when the device is + * completely stalled due to some error conditions, or when there are 1000 + * dd tasks writing to a slow 10MB/s USB key. * In the other normal situations, it acts more gently by throttling the tasks * more (rather than completely block them) when the wb dirty pages go high. * @@ -855,19 +857,20 @@ static void mdtc_calc_avail(struct dirty_throttle_control *mdtc, * The wb's share of dirty limit will be adapting to its throughput and * bounded by the bdi->min_ratio and/or bdi->max_ratio parameters, if set. * - * Return: @wb's dirty limit in pages. The term "dirty" in the context of - * dirty balancing includes all PG_dirty and PG_writeback pages. + * Return: @wb's dirty limit in pages. For dirty throttling limit, the term + * "dirty" in the context of dirty balancing includes all PG_dirty and + * PG_writeback pages. */ -static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc) +static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc, + unsigned long thresh) { struct wb_domain *dom = dtc_dom(dtc); - unsigned long thresh = dtc->thresh; u64 wb_thresh; unsigned long numerator, denominator; unsigned long wb_min_ratio, wb_max_ratio; /* - * Calculate this BDI's share of the thresh ratio. + * Calculate this wb's share of the thresh ratio. */ fprop_fraction_percpu(&dom->completions, dtc->wb_completions, &numerator, &denominator); @@ -887,9 +890,9 @@ static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc) unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh) { - struct dirty_throttle_control gdtc = { GDTC_INIT(wb), - .thresh = thresh }; - return __wb_calc_thresh(&gdtc); + struct dirty_throttle_control gdtc = { GDTC_INIT(wb) }; + + return __wb_calc_thresh(&gdtc, thresh); } unsigned long cgwb_calc_thresh(struct bdi_writeback *wb) @@ -908,7 +911,7 @@ unsigned long cgwb_calc_thresh(struct bdi_writeback *wb) mdtc_calc_avail(&mdtc, filepages, headroom); domain_dirty_limits(&mdtc); - return __wb_calc_thresh(&mdtc); + return __wb_calc_thresh(&mdtc, mdtc.thresh); } /* @@ -1655,7 +1658,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc) * wb_position_ratio() will let the dirtier task progress * at some rate <= (write_bw / 2) for bringing down wb_dirty. */ - dtc->wb_thresh = __wb_calc_thresh(dtc); + dtc->wb_thresh = __wb_calc_thresh(dtc, dtc->thresh); dtc->wb_bg_thresh = dtc->thresh ? div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
Originally, __wb_calc_thresh always calculate wb's share of dirty throttling threshold. By getting thresh of wb_domain from caller, __wb_calc_thresh could be used for both dirty throttling and dirty background threshold. This is a preparation to correct threshold calculation of wb in cgroup. Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> --- mm/page-writeback.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-)