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([2602:47:d483:7301:4e3c:f4a4:b92a:b5ab]) by smtp.gmail.com with ESMTPSA id v10-20020a63b64a000000b0055387ffef10sm7372623pgt.24.2023.08.22.11.11.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Aug 2023 11:11:37 -0700 (PDT) Message-ID: Date: Tue, 22 Aug 2023 11:11:36 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH 21/22] Implement shmat(2) and shmdt(2) Content-Language: en-US To: Warner Losh Cc: Karim Taha , qemu-devel@nongnu.org, Stacey Son References: <20230819094806.14965-1-kariem.taha2.7@gmail.com> <20230819094806.14965-22-kariem.taha2.7@gmail.com> From: Richard Henderson In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::429; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x429.google.com X-Spam_score_int: -38 X-Spam_score: -3.9 X-Spam_bar: --- X-Spam_report: (-3.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.767, RCVD_IN_DNSWL_NONE=-0.0001, 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 8/22/23 11:03, Warner Losh wrote: > Hmm, bug with linux-user as well, because here we should re-establish the reserved_va > reservation. > > > ... of the shared memory region we just detached? Right? Correct. On a related note, on FreeBSD is there any practical difference between PROT_NONE, MAP_ANON and PROT_NONE, MAP_GUARD for large memory regions? I ask since FreeBSD doesn't have MAP_NORESERVE, which Linux uses to avoid allocation of gigabytes. r~