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Mon, 22 Apr 2024 15:52:43 +0800 (CST) From: Kemeng Shi To: akpm@linux-foundation.org, willy@infradead.org, jack@suse.cz, bfoster@redhat.com, tj@kernel.org Cc: dsterba@suse.com, mjguzik@gmail.com, dhowells@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v4 2/4] writeback: support retrieving per group debug writeback stats of bdi Date: Tue, 23 Apr 2024 00:48:06 +0800 Message-Id: <20240422164808.13627-3-shikemeng@huaweicloud.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20240422164808.13627-1-shikemeng@huaweicloud.com> References: <20240422164808.13627-1-shikemeng@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: Syh0CgCHqg1JFyZmCViLKw--.3978S4 X-Coremail-Antispam: 1UD129KBjvJXoW3Xw15uFyfXw1UKFWkCF1xZrb_yoW7uw15pa 98Gw15Jr4UZr17WFZxAay2qry5tw48trW7X3s7Z3yftFnrtry3tFy8ury8Ary5AF93AFy3 Jan8Cry8GrWkKrJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPab4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUXwA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK 0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4 x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l 84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I 8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AK xVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxV A2Y2ka0xkIwI1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAq x4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r 43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF 7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxV WUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxU ImhFDUUUU X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 46B491A0009 X-Rspam-User: X-Stat-Signature: mnjchm9z9pbo8dketd9bcyupoc446143 X-HE-Tag: 1713772367-319887 X-HE-Meta: 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 hTiNZ5mf 9gKRPbctMgskgwXvsZuVhHN3+r0e8GTa7Y2jSKRqCNeE2+nj+UevMsmm6pu0EyCpVTPU//C5NCcqm+7YmG4qGTT608LhCIIL5qsNclZ/7WTsbI2X1OgNkD/XHLGiuRUwcy2YWkTASG4TvQniajEZgApZDOY+G3EDersD2k2RHEMAqxB6870MtWkEsnnZjPID8i4ELrudmZ8ePpLjomepFd+ipcbzqGH+u4musagrb/P03WJ2LosoNYOKtwB+apKSPAz6d7A4W736Dgl8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add /sys/kernel/debug/bdi/xxx/wb_stats to show per group writeback stats of bdi. Following domain hierarchy is tested: global domain (320G) / \ cgroup domain1(10G) cgroup domain2(10G) | | bdi wb1 wb2 /* per wb writeback info of bdi is collected */ cat /sys/kernel/debug/bdi/252:16/wb_stats WbCgIno: 1 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 102400 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 4094 WbWriteback: 54432 kB WbReclaimable: 766080 kB WbDirtyThresh: 3094760 kB WbDirtied: 1656480 kB WbWritten: 837088 kB WbWriteBandwidth: 132772 kBps b_dirty: 1 b_io: 1 b_more_io: 0 b_dirty_time: 0 state: 7 WbCgIno: 4135 WbWriteback: 15232 kB WbReclaimable: 786688 kB WbDirtyThresh: 2909984 kB WbDirtied: 1482656 kB WbWritten: 681408 kB WbWriteBandwidth: 124848 kBps b_dirty: 0 b_io: 1 b_more_io: 0 b_dirty_time: 0 state: 7 Signed-off-by: Kemeng Shi Acked-by: Tejun Heo --- include/linux/writeback.h | 1 + mm/backing-dev.c | 78 ++++++++++++++++++++++++++++++++++++++- mm/page-writeback.c | 19 ++++++++++ 3 files changed, 96 insertions(+), 2 deletions(-) diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 9845cb62e40b..112d806ddbe4 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 cgwb_calc_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 089146feb830..6ecd11bdce6e 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -155,19 +155,93 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v) } DEFINE_SHOW_ATTRIBUTE(bdi_debug_stats); +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\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); + + rcu_read_lock(); + list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) { + struct wb_stats stats = { .dirty_thresh = dirty_thresh }; + + if (!wb_tryget(wb)) + continue; + + collect_wb_stats(&stats, wb); + + /* + * Calculate thresh of wb in writeback cgroup which is min of + * thresh in global domain and thresh in cgroup domain. Drop + * rcu lock because cgwb_calc_thresh may sleep in + * cgroup_rstat_flush. We can do so here because we have a ref. + */ + if (mem_cgroup_wb_domain(wb)) { + rcu_read_unlock(); + stats.wb_thresh = min(stats.wb_thresh, cgwb_calc_thresh(wb)); + rcu_read_lock(); + } + + wb_stats_show(m, wb, &stats); + + wb_put(wb); + } + rcu_read_unlock(); + + return 0; +} +DEFINE_SHOW_ATTRIBUTE(cgwb_debug_stats); + static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) { bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); debugfs_create_file("stats", 0444, bdi->debug_dir, bdi, &bdi_debug_stats_fops); + debugfs_create_file("wb_stats", 0444, bdi->debug_dir, bdi, + &cgwb_debug_stats_fops); } static void bdi_debug_unregister(struct backing_dev_info *bdi) { debugfs_remove_recursive(bdi->debug_dir); } -#else +#else /* CONFIG_DEBUG_FS */ static inline void bdi_debug_init(void) { } @@ -178,7 +252,7 @@ static inline void bdi_debug_register(struct backing_dev_info *bdi, static inline void bdi_debug_unregister(struct backing_dev_info *bdi) { } -#endif +#endif /* CONFIG_DEBUG_FS */ static ssize_t read_ahead_kb_store(struct device *dev, struct device_attribute *attr, diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 3e19b87049db..3bb3bed102ef 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -892,6 +892,25 @@ unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh) return __wb_calc_thresh(&gdtc); } +unsigned long cgwb_calc_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 = 0, headroom = 0, writeback = 0; + + 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); +} + /* * setpoint - dirty 3 * f(dirty) := 1.0 + (----------------)