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McKenney" To: Thomas Gleixner Cc: Ankur Arora , Linus Torvalds , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, willy@infradead.org, mgorman@suse.de, rostedt@goodmis.org, jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com, jgross@suse.com, andrew.cooper3@citrix.com, Frederic Weisbecker , urezki@gmail.com Subject: Re: [PATCH v2 7/9] sched: define TIF_ALLOW_RESCHED Message-ID: <63d6ddfa-16ca-4c19-b542-a95f27d72f96@paulmck-laptop> Reply-To: paulmck@kernel.org References: <87ttrngmq0.ffs@tglx> <87jzshhexi.ffs@tglx> <87il74qghh.fsf@oracle.com> <7520a5b9-b604-4da2-b874-32505f175f39@paulmck-laptop> <875y334k6m.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <875y334k6m.ffs@tglx> X-Rspamd-Queue-Id: 7CB0C100003 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: qdchs4cxg7itemqw3befm8bn4schnuct X-HE-Tag: 1697671562-636897 X-HE-Meta: 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 r8/b1yU1 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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: On Thu, Oct 19, 2023 at 12:53:05AM +0200, Thomas Gleixner wrote: > On Wed, Oct 18 2023 at 10:51, Paul E. McKenney wrote: > > On Wed, Oct 18, 2023 at 05:09:46AM -0700, Ankur Arora wrote: > > Can you folks please trim your replies. It's annoying to scroll > through hundreds of quoted lines to figure out that nothing is there. > > >> This probably allows for more configuration flexibility across archs? > >> Would allow for TREE_RCU=y, for instance. That said, so far I've only > >> been working with PREEMPT_RCU=y.) > > > > Then this is a bug that needs to be fixed. We need a way to make > > RCU readers non-preemptible. > > Why? So that we don't get tail latencies from preempted RCU readers that result in memory-usage spikes on systems that have good and sufficient quantities of memory, but which do not have enough memory to tolerate readers being preempted. Thanx, Paul