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[90.235.18.147]) by smtp.gmail.com with ESMTPSA id t1-20020ac24c01000000b004f37b88eacfsm1111065lfq.187.2023.05.16.06.42.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 May 2023 06:42:23 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Tue, 16 May 2023 15:42:20 +0200 To: Thomas Gleixner Cc: "Russell King (Oracle)" , Andrew Morton , linux-mm@kvack.org, Christoph Hellwig , Uladzislau Rezki , Lorenzo Stoakes , Peter Zijlstra , Baoquan He , John Ogness , linux-arm-kernel@lists.infradead.org, Mark Rutland , Marc Zyngier , x86@kernel.org Subject: Re: Excessive TLB flush ranges Message-ID: References: <87a5y5a6kj.ffs@tglx> <87353x9y3l.ffs@tglx> <87zg658fla.ffs@tglx> <87r0rg93z5.ffs@tglx> <87cz308y3s.ffs@tglx> <87y1lo7a0z.ffs@tglx> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87y1lo7a0z.ffs@tglx> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230516_064229_219756_7A7AB8FA X-CRM114-Status: GOOD ( 13.31 ) 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 > _vm_unmap_aliases() collects dirty ranges from per cpu vmap_block_queue > (what ever that is) and hands a start..end range to > __purge_vmap_area_lazy(). > > As I pointed out already, this can also end up being an excessive range > because there is no guarantee that those individual collected ranges are > consecutive. Though I have no idea how to cure that right now. > > AFAICT this was done to spare flush IPIs, but the mm folks should be > able to explain that properly. > This is done to prevent generating IPIs. That is why the whole range is calculated once and a flush occurs only once for all lazily registered VAs. -- Uladzislau Rezki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel