| Message ID | 20240320110222.6564-3-shikemeng@huaweicloud.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Improve visibility of writeback | expand |
On Wed, Mar 20, 2024 at 07:02:18PM +0800, Kemeng Shi wrote: > diff --git a/include/linux/writeback.h b/include/linux/writeback.h > index 9845cb62e40b..bb1ce1123b52 100644 > --- a/include/linux/writeback.h > +++ b/include/linux/writeback.h > @@ -355,6 +355,7 @@ int dirtytime_interval_handler(struct ctl_table *table, int write, > > void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty); > unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh); > +unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb); Would cgwb_calc_thresh() be an easier name? Thanks.
on 3/20/2024 11:01 PM, Tejun Heo wrote: > On Wed, Mar 20, 2024 at 07:02:18PM +0800, Kemeng Shi wrote: >> diff --git a/include/linux/writeback.h b/include/linux/writeback.h >> index 9845cb62e40b..bb1ce1123b52 100644 >> --- a/include/linux/writeback.h >> +++ b/include/linux/writeback.h >> @@ -355,6 +355,7 @@ int dirtytime_interval_handler(struct ctl_table *table, int write, >> >> void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty); >> unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh); >> +unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb); > > Would cgwb_calc_thresh() be an easier name? > Sure, will rename it in next version. Thansk! > Thanks. >
On Wed 20-03-24 19:02:18, Kemeng Shi wrote: > Add /sys/kernel/debug/bdi/xxx/wb_stats to show per group writeback stats > of bdi. > > Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> ... > +unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb) > +{ > + struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; > + struct dirty_throttle_control mdtc = { MDTC_INIT(wb, &gdtc) }; > + unsigned long filepages, headroom, writeback; > + > + gdtc.avail = global_dirtyable_memory(); > + gdtc.dirty = global_node_page_state(NR_FILE_DIRTY) + > + global_node_page_state(NR_WRITEBACK); > + > + mem_cgroup_wb_stats(wb, &filepages, &headroom, > + &mdtc.dirty, &writeback); > + mdtc.dirty += writeback; > + mdtc_calc_avail(&mdtc, filepages, headroom); > + domain_dirty_limits(&mdtc); > + > + return __wb_calc_thresh(&mdtc, mdtc.thresh); > +} I kind of wish we didn't replicate this logic from balance_dirty_pages() and wb_over_bg_thresh() into yet another place. But the refactoring would be kind of difficult. So OK. Honza
on 3/26/2024 8:24 PM, Jan Kara wrote: > On Wed 20-03-24 19:02:18, Kemeng Shi wrote: >> Add /sys/kernel/debug/bdi/xxx/wb_stats to show per group writeback stats >> of bdi. >> >> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> > > ... > >> +unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb) >> +{ >> + struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; >> + struct dirty_throttle_control mdtc = { MDTC_INIT(wb, &gdtc) }; >> + unsigned long filepages, headroom, writeback; >> + >> + gdtc.avail = global_dirtyable_memory(); >> + gdtc.dirty = global_node_page_state(NR_FILE_DIRTY) + >> + global_node_page_state(NR_WRITEBACK); >> + >> + mem_cgroup_wb_stats(wb, &filepages, &headroom, >> + &mdtc.dirty, &writeback); >> + mdtc.dirty += writeback; >> + mdtc_calc_avail(&mdtc, filepages, headroom); >> + domain_dirty_limits(&mdtc); >> + >> + return __wb_calc_thresh(&mdtc, mdtc.thresh); >> +} > > I kind of wish we didn't replicate this logic from balance_dirty_pages() > and wb_over_bg_thresh() into yet another place. But the refactoring would > be kind of difficult. So OK. Thanks for review the code. I have considered about this. It's difficult and will introduce a lot change to non-debug code which make this series uneasy to review. I will submit another patch for refactoring if I could find a way to clean the code. Kemeng > > Honza >
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 9845cb62e40b..bb1ce1123b52 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -355,6 +355,7 @@ int dirtytime_interval_handler(struct ctl_table *table, int write, void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty); unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh); +unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb); void wb_update_bandwidth(struct bdi_writeback *wb); diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 788702b6c5dd..bfc4079dc7fe 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -95,12 +95,77 @@ static void bdi_collect_stats(struct backing_dev_info *bdi, collect_wb_stats(stats, wb); mutex_unlock(&bdi->cgwb_release_mutex); } +static void wb_stats_show(struct seq_file *m, struct bdi_writeback *wb, + struct wb_stats *stats) +{ + + seq_printf(m, + "WbCgIno: %10lu\n" + "WbWriteback: %10lu kB\n" + "WbReclaimable: %10lu kB\n" + "WbDirtyThresh: %10lu kB\n" + "WbDirtied: %10lu kB\n" + "WbWritten: %10lu kB\n" + "WbWriteBandwidth: %10lu kBps\n" + "b_dirty: %10lu\n" + "b_io: %10lu\n" + "b_more_io: %10lu\n" + "b_dirty_time: %10lu\n" + "state: %10lx\n", + cgroup_ino(wb->memcg_css->cgroup), + K(stats->nr_writeback), + K(stats->nr_reclaimable), + K(stats->wb_thresh), + K(stats->nr_dirtied), + K(stats->nr_written), + K(wb->avg_write_bandwidth), + stats->nr_dirty, + stats->nr_io, + stats->nr_more_io, + stats->nr_dirty_time, + wb->state); +} + +static int cgwb_debug_stats_show(struct seq_file *m, void *v) +{ + struct backing_dev_info *bdi = m->private; + unsigned long background_thresh; + unsigned long dirty_thresh; + struct bdi_writeback *wb; + struct wb_stats stats; + + global_dirty_limits(&background_thresh, &dirty_thresh); + + mutex_lock(&bdi->cgwb_release_mutex); + list_for_each_entry(wb, &bdi->wb_list, bdi_node) { + memset(&stats, 0, sizeof(stats)); + stats.dirty_thresh = dirty_thresh; + collect_wb_stats(&stats, wb); + + if (mem_cgroup_wb_domain(wb) != NULL) + stats.wb_thresh = min(stats.wb_thresh, wb_calc_cg_thresh(wb)); + + wb_stats_show(m, wb, &stats); + } + mutex_unlock(&bdi->cgwb_release_mutex); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(cgwb_debug_stats); + +static void cgwb_debug_register(struct backing_dev_info *bdi) +{ + debugfs_create_file("wb_stats", 0444, bdi->debug_dir, bdi, + &cgwb_debug_stats_fops); +} #else static void bdi_collect_stats(struct backing_dev_info *bdi, struct wb_stats *stats) { collect_wb_stats(stats, &bdi->wb); } + +static inline void cgwb_debug_register(struct backing_dev_info *bdi) { } #endif static int bdi_debug_stats_show(struct seq_file *m, void *v) @@ -158,6 +223,7 @@ static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) debugfs_create_file("stats", 0444, bdi->debug_dir, bdi, &bdi_debug_stats_fops); + cgwb_debug_register(bdi); } static void bdi_debug_unregister(struct backing_dev_info *bdi) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 0e20467367fe..ba1b6b5ae5d6 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -893,6 +893,25 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh) return __wb_calc_thresh(&gdtc, thresh); } +unsigned long wb_calc_cg_thresh(struct bdi_writeback *wb) +{ + struct dirty_throttle_control gdtc = { GDTC_INIT_NO_WB }; + struct dirty_throttle_control mdtc = { MDTC_INIT(wb, &gdtc) }; + unsigned long filepages, headroom, writeback; + + gdtc.avail = global_dirtyable_memory(); + gdtc.dirty = global_node_page_state(NR_FILE_DIRTY) + + global_node_page_state(NR_WRITEBACK); + + mem_cgroup_wb_stats(wb, &filepages, &headroom, + &mdtc.dirty, &writeback); + mdtc.dirty += writeback; + mdtc_calc_avail(&mdtc, filepages, headroom); + domain_dirty_limits(&mdtc); + + return __wb_calc_thresh(&mdtc, mdtc.thresh); +} + /* * setpoint - dirty 3 * f(dirty) := 1.0 + (----------------)
Add /sys/kernel/debug/bdi/xxx/wb_stats to show per group writeback stats of bdi. Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> --- include/linux/writeback.h | 1 + mm/backing-dev.c | 66 +++++++++++++++++++++++++++++++++++++++ mm/page-writeback.c | 19 +++++++++++ 3 files changed, 86 insertions(+)