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[99.254.114.190]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-467923f5caasm15199581cf.48.2024.12.12.08.20.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Dec 2024 08:20:40 -0800 (PST) Date: Thu, 12 Dec 2024 11:20:39 -0500 From: Peter Xu To: Daniil Tatianin Cc: Paolo Bonzini , Stefan Weil , Fabiano Rosas , qemu-devel@nongnu.org Subject: Re: [PATCH v3 4/4] overcommit: introduce mem-lock=on-fault Message-ID: References: <20241211230433.1371327-1-d-tatianin@yandex-team.ru> <20241211230433.1371327-5-d-tatianin@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20241211230433.1371327-5-d-tatianin@yandex-team.ru> Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.496, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Dec 12, 2024 at 02:04:33AM +0300, Daniil Tatianin wrote: > Locking the memory without MCL_ONFAULT instantly prefaults any mmaped > anonymous memory with a write-fault, which introduces a lot of extra > overhead in terms of memory usage when all you want to do is to prevent > kcompactd from migrating and compacting QEMU pages. Add an option to > only lock pages lazily as they're faulted by the process by using > MCL_ONFAULT if asked. > > Signed-off-by: Daniil Tatianin Reviewed-by: Peter Xu -- Peter Xu