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ESMTPSA id d9443c01a7336-212883fd550sm7691145ad.254.2024.11.21.00.05.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Nov 2024 00:05:34 -0800 (PST) From: Jim Zhao To: shikemeng@huaweicloud.com Cc: jack@suse.cz, akpm@linux-foundation.org, jimzhao.ai@gmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, willy@infradead.org Subject: Re: [PATCH v2] mm/page-writeback: Raise wb_thresh to prevent write blocking with strictlimit Date: Thu, 21 Nov 2024 16:05:31 +0800 Message-Id: <20241121080531.567995-1-jimzhao.ai@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <5584d4d5-73c8-2a12-f11e-6f19c216656b@huaweicloud.com> References: <5584d4d5-73c8-2a12-f11e-6f19c216656b@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > on 11/19/2024 8:29 PM, Jim Zhao wrote: > > Thanks, Jan, I just sent patch v2, could you please review it ? > > > > And I found the debug info in the bdi stats. > > The BdiDirtyThresh value may be greater than DirtyThresh, and after applying this patch, the value of BdiDirtyThresh could become even larger. > > > > without patch: > > --- > > root@ubuntu:/sys/kernel/debug/bdi/8:0# cat stats > > BdiWriteback: 0 kB > > BdiReclaimable: 96 kB > > BdiDirtyThresh: 1346824 kB > > DirtyThresh: 673412 kB > > BackgroundThresh: 336292 kB > > BdiDirtied: 19872 kB > > BdiWritten: 19776 kB > > BdiWriteBandwidth: 0 kBps > > b_dirty: 0 > > b_io: 0 > > b_more_io: 0 > > b_dirty_time: 0 > > bdi_list: 1 > > state: 1 > > > > with patch: > > --- > > root@ubuntu:/sys/kernel/debug/bdi/8:0# cat stats > > BdiWriteback: 96 kB > > BdiReclaimable: 192 kB > > BdiDirtyThresh: 3090736 kB > > DirtyThresh: 650716 kB > > BackgroundThresh: 324960 kB > > BdiDirtied: 472512 kB > > BdiWritten: 470592 kB > > BdiWriteBandwidth: 106268 kBps > > b_dirty: 2 > > b_io: 0 > > b_more_io: 0 > > b_dirty_time: 0 > > bdi_list: 1 > > state: 1 > > > > > > @kemeng, is this a normal behavior or an issue ? > Hello, this is not a normal behavior, could you aslo send the content in > wb_stats and configuired bdi_min_ratio. > I think the improper use of bdi_min_ratio may cause the issue. the min_ratio is 0 --- root@ubuntu:/sys/class/bdi/8:0# cat min_bytes 0 root@ubuntu:/sys/class/bdi/8:0# cat min_ratio 0 root@ubuntu:/sys/class/bdi/8:0# cat min_ratio_fine 0 wb_stats: --- root@ubuntu:/sys/kernel/debug/bdi/8:0# cat stats BdiWriteback: 0 kB BdiReclaimable: 480 kB BdiDirtyThresh: 1664700 kB DirtyThresh: 554900 kB BackgroundThresh: 277108 kB BdiDirtied: 82752 kB BdiWritten: 82752 kB BdiWriteBandwidth: 205116 kBps b_dirty: 6 b_io: 0 b_more_io: 0 b_dirty_time: 0 bdi_list: 1 state: 1 root@ubuntu:/sys/kernel/debug/bdi/8:0# cat wb_stats WbCgIno: 1 WbWriteback: 0 kB WbReclaimable: 96 kB WbDirtyThresh: 0 kB WbDirtied: 33600 kB WbWritten: 33600 kB WbWriteBandwidth: 148 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 416 WbWriteback: 0 kB WbReclaimable: 288 kB WbDirtyThresh: 554836 kB WbDirtied: 47616 kB WbWritten: 47424 kB WbWriteBandwidth: 168 kBps b_dirty: 1 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 5 WbCgIno: 1319 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: 1835 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: 29 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 101752 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 158 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 101756 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 2498 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: 3358 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: 3573 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: 3659 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: 3186 WbWriteback: 0 kB WbReclaimable: 96 kB WbDirtyThresh: 554788 kB WbDirtied: 1056 kB WbWritten: 1152 kB WbWriteBandwidth: 152 kBps b_dirty: 1 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 5 WbCgIno: 3315 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 384 kB WbWritten: 384 kB WbWriteBandwidth: 98876 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 72 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 554836 kB WbDirtied: 96 kB WbWritten: 192 kB WbWriteBandwidth: 4 kBps b_dirty: 1 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 5 WbCgIno: 3616 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 100308 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 4132 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: 3401 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: 4517 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: 4846 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: 4982 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 100468 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 5369 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 96 kB WbWriteBandwidth: 75104 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 5627 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: 6235 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: 6192 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: 6500 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: 4617 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: 6958 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: 5670 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 102400 kBps b_dirty: 1 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 5 WbCgIno: 5870 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: 5025 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: 7990 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 91500 kBps b_dirty: 1 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 5 WbCgIno: 8033 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: 2842 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: 11129 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 ubuntu24.04 desktop + kernel 6.12.0 default cgroups, not configured manually. --- Thanks Jim Zhao