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Wed, 20 Mar 2024 17:22:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id Ay0JDGEb+2VhegAAD6G6ig (envelope-from ); Wed, 20 Mar 2024 17:22:41 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id D0E85A080F; Wed, 20 Mar 2024 18:22:40 +0100 (CET) Date: Wed, 20 Mar 2024 18:22:40 +0100 From: Jan Kara To: Kemeng Shi Cc: akpm@linux-foundation.org, tj@kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, willy@infradead.org, bfoster@redhat.com, jack@suse.cz, dsterba@suse.com, mjguzik@gmail.com, dhowells@redhat.com, peterz@infradead.org Subject: Re: [PATCH 0/6] Improve visibility of writeback Message-ID: <20240320172240.7buswiv7zj2m5odg@quack3> References: <20240320110222.6564-1-shikemeng@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240320110222.6564-1-shikemeng@huaweicloud.com> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 4897D40014 X-Stat-Signature: s6ob3riwoa945kr631itzjknc3rusq16 X-Rspam-User: X-HE-Tag: 1710955363-221085 X-HE-Meta: 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 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: On Wed 20-03-24 19:02:16, Kemeng Shi wrote: > This series tries to improve visilibity of writeback. Patch 1 make > /sys/kernel/debug/bdi/xxx/stats show writeback info of whole bdi > instead of only writeback info in root cgroup. Patch 2 add a new > debug file /sys/kernel/debug/bdi/xxx/wb_stats to show per wb writeback > info. Patch 4 add wb_monitor.py to monitor basic writeback info > of running system, more info could be added on demand. Rest patches > are some random cleanups. More details can be found in respective > patches. Thanks! > > Following domain hierarchy is tested: > global domain (320G) > / \ > cgroup domain1(10G) cgroup domain2(10G) > | | > bdi wb1 wb2 > > /* all writeback info of bdi is successfully collected */ > # cat /sys/kernel/debug/bdi/252:16/stats: > BdiWriteback: 448 kB > BdiReclaimable: 1303904 kB > BdiDirtyThresh: 189914124 kB > DirtyThresh: 195337564 kB > BackgroundThresh: 32516508 kB > BdiDirtied: 3591392 kB > BdiWritten: 2287488 kB > BdiWriteBandwidth: 322248 kBps > b_dirty: 0 > b_io: 0 > b_more_io: 2 > b_dirty_time: 0 > bdi_list: 1 > state: 1 > > /* per wb writeback info is collected */ > # cat /sys/kernel/debug/bdi/252:16/wb_stats: > cat 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: 4284 > WbWriteback: 448 kB > WbReclaimable: 818944 kB > WbDirtyThresh: 3096524 kB > WbDirtied: 2266880 kB > WbWritten: 1447936 kB > WbWriteBandwidth: 214036 kBps > b_dirty: 0 > b_io: 0 > b_more_io: 1 > b_dirty_time: 0 > state: 5 > WbCgIno: 4325 > WbWriteback: 224 kB > WbReclaimable: 819392 kB > WbDirtyThresh: 2920088 kB > WbDirtied: 2551808 kB > WbWritten: 1732416 kB > WbWriteBandwidth: 201832 kBps > b_dirty: 0 > b_io: 0 > b_more_io: 1 > b_dirty_time: 0 > state: 5 > > /* monitor writeback info */ > # ./wb_monitor.py 252:16 -c > writeback reclaimable dirtied written avg_bw > 252:16_1 0 0 0 0 102400 > 252:16_4284 672 820064 9230368 8410304 685612 > 252:16_4325 896 819840 10491264 9671648 652348 > 252:16 1568 1639904 19721632 18081952 1440360 > > > writeback reclaimable dirtied written avg_bw > 252:16_1 0 0 0 0 102400 > 252:16_4284 672 820064 9230368 8410304 685612 > 252:16_4325 896 819840 10491264 9671648 652348 > 252:16 1568 1639904 19721632 18081952 1440360 > ... So I'm wondering: Are you implementing this just because this looks interesting or do you have a real need for the functionality? Why? Honza -- Jan Kara SUSE Labs, CR