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Thu, 05 Nov 2026 13:47:17 -0800 (PST) Received: from [192.168.1.22] ([83.231.69.9]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4b6c776c90asm8123125e9.4.2026.11.05.13.47.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 05 Nov 2026 13:47:17 -0800 (PST) Message-ID: <0076d3d4-465a-4dcd-b789-aa11c112b74f@gmail.com> Date: Thu, 5 Nov 2026 22:47:16 +0100 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/3] Revert "mm/khugepaged: remove definition of struct khugepaged_mm_slot" To: "Lorenzo Stoakes (ARM)" , David Hildenbrand , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20261105-khugepaged-latency-fix-v2-0-4384bbfe4606@kernel.org> <20261105-khugepaged-latency-fix-v2-1-4384bbfe4606@kernel.org> Content-Language: en-US From: "Jose A. Perez de Azpillaga" In-Reply-To: <20261105-khugepaged-latency-fix-v2-1-4384bbfe4606@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/5/26 9:57 PM, Lorenzo Stoakes (ARM) wrote: > This partially reverts commit b4c9ffb54b32 ("mm/khugepaged: remove > definition of struct khugepaged_mm_slot"), as a subsequent commit needs to > resurrect this type to store additional data alongside the mm_slot. > > The stated intent of the commit was to address a NULL check in > __khugepaged_exit(): > > mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot); > > slot can be NULL and mm_slot_entry() is an alias for container_of(), so > this is container_of() a NULL value. > > This was benign as there was only 1 field in khugepaged_mm_slot (offsetting > NULL at 0 results in NULL), however it was right to fix this, so retain the > fix. > > It also unwrapped KMEM_CACHE() in khugepaged_init(). This was a mistake, > and was itself reverted in commit c14bdcc9f274 ("mm/khugepaged: use > KMEM_CACHE()"). Therefore, retain the KMEM_CACHE() form in this revert. > > Reviewed-by: David Hildenbrand (Arm) > Reviewed-by: Lance Yang > Signed-off-by: Lorenzo Stoakes (ARM) LGTM: Reviewed-by: Jose A. Perez de Azpillaga -- cheers, jose a. p-a