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Fri, 07 May 2021 09:46:29 -0700 (PDT) Received: from [192.168.1.11] ([71.212.144.24]) by smtp.gmail.com with ESMTPSA id h9sm4737946pgl.67.2021.05.07.09.46.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 07 May 2021 09:46:29 -0700 (PDT) Subject: Re: [PATCH 18/23] ui/vnc-enc-hextile: Use definitions to avoid dynamic stack allocation To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , qemu-devel@nongnu.org References: <20210505211047.1496765-1-philmd@redhat.com> <20210505211047.1496765-19-philmd@redhat.com> From: Richard Henderson Message-ID: Date: Fri, 7 May 2021 09:46:27 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210505211047.1496765-19-philmd@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::529; envelope-from=richard.henderson@linaro.org; helo=mail-pg1-x529.google.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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , qemu-block@nongnu.org, qemu-ppc@nongnu.org, Gerd Hoffmann , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/5/21 2:10 PM, Philippe Mathieu-Daudé wrote: > We know 'pf.bytes_per_pixel' will be at most 'VNC_SERVER_FB_BYTES' > (which is actually 4 bytes for 32bpp). Instead of having the compiler > use variable-length array, use this 'small' maximum length and > autofree to allocate the buffer on the heap. > > Signed-off-by: Philippe Mathieu-Daudé > --- > ui/vnc-enc-hextile-template.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) Wait, you know the value is small (max 4), and you don't want to allocate a constant 1k on the stack? r~