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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2647bf5bf7asm63906485ad.1.2025.09.15.22.32.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Sep 2025 22:32:23 -0700 (PDT) Date: Mon, 15 Sep 2025 22:32:14 -0700 (PDT) From: Hugh Dickins To: Lance Yang cc: akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, ioworker0@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH mm-new 1/3] mm/khugepaged: skip unsuitable VMAs earlier in khugepaged_scan_mm_slot() In-Reply-To: <20250914143547.27687-2-lance.yang@linux.dev> Message-ID: References: <20250914143547.27687-1-lance.yang@linux.dev> <20250914143547.27687-2-lance.yang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Sun, 14 Sep 2025, Lance Yang wrote: > From: Lance Yang > > Let's skip unsuitable VMAs early in the khugepaged scan; specifically, > mlocked VMAs should not be touched. Why? That's a change in behaviour, isn't it? I'm aware that hugepage collapse on an mlocked VMA can insert a fault latency, not universally welcome; but I've not seen discussion, let alone agreement, that current behaviour should be changed. Somewhere in yet-to-be-read mail? Please give us a link. Hugh