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Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1pkQDx-00AXes-0w; Thu, 06 Apr 2023 14:04:25 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 94388300194; Thu, 6 Apr 2023 16:04:23 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 7CEE5212E36AC; Thu, 6 Apr 2023 16:04:23 +0200 (CEST) Date: Thu, 6 Apr 2023 16:04:23 +0200 From: Peter Zijlstra To: Marcelo Tosatti Cc: Frederic Weisbecker , Yair Podemsky , linux@armlinux.org.uk, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, will@kernel.org, aneesh.kumar@linux.ibm.com, akpm@linux-foundation.org, arnd@arndb.de, keescook@chromium.org, paulmck@kernel.org, jpoimboe@kernel.org, samitolvanen@google.com, ardb@kernel.org, juerg.haefliger@canonical.com, rmk+kernel@armlinux.org.uk, geert+renesas@glider.be, tony@atomide.com, linus.walleij@linaro.org, sebastian.reichel@collabora.com, nick.hawkins@hpe.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, vschneid@redhat.com, dhildenb@redhat.com, alougovs@redhat.com, jannh@google.com Subject: Re: [PATCH 3/3] mm/mmu_gather: send tlb_remove_table_smp_sync IPI only to CPUs in kernel mode Message-ID: <20230406140423.GA386634@hirez.programming.kicks-ass.net> References: <20230404134224.137038-1-ypodemsk@redhat.com> <20230404134224.137038-4-ypodemsk@redhat.com> <20230405195226.GB365912@hirez.programming.kicks-ass.net> <20230406132928.GM386572@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230406132928.GM386572@hirez.programming.kicks-ass.net> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Apr 06, 2023 at 03:29:28PM +0200, Peter Zijlstra wrote: > On Thu, Apr 06, 2023 at 09:38:50AM -0300, Marcelo Tosatti wrote: > > > > To actually hit this path you're doing something really dodgy. > > > > Apparently khugepaged is using the same infrastructure: > > > > $ grep tlb_remove_table khugepaged.c > > tlb_remove_table_sync_one(); > > tlb_remove_table_sync_one(); > > > > So just enabling khugepaged will hit that path. > > Urgh, WTF.. > > Let me go read that stuff :/ At the very least the one on collapse_and_free_pmd() could easily become a call_rcu() based free. I'm not sure I'm following what collapse_huge_page() does just yet. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel