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See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 1C249A001F X-Stat-Signature: a6pykog1t5hunpgjkzx1pompi48qab7u X-HE-Tag: 1758564592-516937 X-HE-Meta: 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 n6iv1NEK 5kkkSuLUczTf39Wbxa/0chH1Wqn00oqARBmH3rlG+GRF91myaAYW4NooVggzx4e7drnKzj7kW0lSsGeQNw0AvhnY+B8pNWQosTbXm7hBc+5xidJXqJhHJ88KilMEJJ8SYrmNW 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 Mon, Sep 22, 2025 at 11:29:15AM +0800, zhaoyang.huang wrote: > From: Zhaoyang Huang > > For now, my android system with per pid memcgv2 setup are suffering > high block_rq_issue to block_rq_complete latency which is actually > introduced by schedule latency of too many kworker threads. By further > investigation, we found that the EAS scheduler which will pack small > load tasks into one CPU core will make this scenario worse. This commit > would like to introduce a way of synchronized read to be helpful on > this scenario. The I2C of loop device's request reduced from 14ms to > 2.1ms under fio test. So fix the scheduler, or create less helper threads, but this work around really look like fixing the symptoms instead of even trying to aim for the root cause.