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[99.254.121.117]) by smtp.gmail.com with ESMTPSA id 5614622812f47-3de225c532fsm2602497b6e.43.2024.08.27.10.57.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Aug 2024 10:57:06 -0700 (PDT) Date: Tue, 27 Aug 2024 13:57:04 -0400 From: Peter Xu To: David Hildenbrand Cc: qemu-devel@nongnu.org, Peter Maydell , qemu-stable@nongnu.org, Stefan Hajnoczi , Paolo Bonzini , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH v1] softmmu/physmem: fix memory leak in dirty_memory_extend() Message-ID: References: <20240827083715.257768-1-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240827083715.257768-1-david@redhat.com> 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: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 Tue, Aug 27, 2024 at 10:37:15AM +0200, David Hildenbrand wrote: > /* Called with ram_list.mutex held */ > -static void dirty_memory_extend(ram_addr_t old_ram_size, > - ram_addr_t new_ram_size) > +static void dirty_memory_extend(ram_addr_t new_ram_size) > { > - ram_addr_t old_num_blocks = DIV_ROUND_UP(old_ram_size, > - DIRTY_MEMORY_BLOCK_SIZE); > ram_addr_t new_num_blocks = DIV_ROUND_UP(new_ram_size, > DIRTY_MEMORY_BLOCK_SIZE); > int i; > > - /* Only need to extend if block count increased */ > - if (new_num_blocks <= old_num_blocks) { > - return; > - } One nitpick here: IMHO we could move the n_blocks cache in ram_list instead, then we keep the check here and avoid caching it three times with the same value. > - > for (i = 0; i < DIRTY_MEMORY_NUM; i++) { > DirtyMemoryBlocks *old_blocks; > DirtyMemoryBlocks *new_blocks; > + ram_addr_t old_num_blocks = 0; > int j; > > old_blocks = qatomic_rcu_read(&ram_list.dirty_memory[i]); > + if (old_blocks) { > + old_num_blocks = old_blocks->num_blocks; > + > + /* Only need to extend if block count increased */ > + if (new_num_blocks <= old_num_blocks) { > + return; > + } > + } -- Peter Xu