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charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Rspam-User: X-Rspamd-Queue-Id: 70C5DC0036 X-Rspamd-Server: rspam01 X-Stat-Signature: 3ip69e61f1dard6p6t5a35kfmsnmi57p X-HE-Tag: 1678798875-537296 X-HE-Meta: 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 Au16MCnV bNQ1OU+BOS4D5GCT0GCVai9mn2tkAp8gqMuVLm8msdLyX5qQXvFF4bguA2zcHngviCpjVLiuRlcKc3lA+7Y6fCGXFNiF/dEnyQotrtMvbd2+vLflzjpZr8YcWalvnRXKq/0xByFEBUUEs/fad3iZz3BK+yE/uk3Y8H+EAuPrpG1sVNrs= 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: On Tue, Mar 14, 2023 at 09:59:37AM -0300, Marcelo Tosatti wrote: > > Why is that a problem? Out-of-sync stats shouldn't cause major problems. > > Or can they? > > Consider SCHED_FIFO task that is polling the network queue (say > testpmd). > > do { > if (net_registers->state & DATA_AVAILABLE) { > process_data)(); > } > } while (!stopped); > > Since this task runs at SCHED_FIFO priority, kworker won't > be scheduled to run (therefore per-CPU vmstats won't be > flushed to global vmstats). > > Or, if testpmd runs at SCHED_OTHER, then the work item to > flush per-CPU vmstats causes > > testpmd -> kworker > kworker: flush per-CPU vmstats > kworker -> testpmd > > And this might cause undesired latencies to the packets being > processed by the testpmd task. This problem is unrelated to the kswapd problem, but both are addressed by the patchset.