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Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1sYHR0-0000000D81o-0yTB; Mon, 29 Jul 2024 03:52:30 +0000 Date: Mon, 29 Jul 2024 04:52:30 +0100 From: Matthew Wilcox To: Barry Song <21cnbao@gmail.com> Cc: akpm@linux-foundation.org, linux-mm@kvack.org, ying.huang@intel.com, baolin.wang@linux.alibaba.com, chrisl@kernel.org, david@redhat.com, hannes@cmpxchg.org, hughd@google.com, kaleshsingh@google.com, kasong@tencent.com, linux-kernel@vger.kernel.org, mhocko@suse.com, minchan@kernel.org, nphamcs@gmail.com, ryan.roberts@arm.com, senozhatsky@chromium.org, shakeel.butt@linux.dev, shy828301@gmail.com, surenb@google.com, v-songbaohua@oppo.com, xiang@kernel.org, yosryahmed@google.com Subject: Re: [PATCH v5 4/4] mm: Introduce per-thpsize swapin control policy Message-ID: References: <20240726094618.401593-1-21cnbao@gmail.com> <20240726094618.401593-5-21cnbao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240726094618.401593-5-21cnbao@gmail.com> X-Stat-Signature: n7xfjz947pzhi4o4kpocy6qufgintn99 X-Rspam-User: X-Rspamd-Queue-Id: 2EFF1120005 X-Rspamd-Server: rspam02 X-HE-Tag: 1722225156-30446 X-HE-Meta: U2FsdGVkX19SqpgFZx2TDBPbJo6nhI6mpwXDVfvuv8ZYDd0EwqaKL+H4NiZCXprGDOwP7PjMIKv8QI+DDVYBFvmrzqgcgZ1G6yTtGTUYBxvLFQza6vN/4QieDO8BeG6EZfPvpgSV5hmD/BAePC5RbMykoKJc1iCLZbbbjNPzu066gUUORexUqtLhrZZCt5JgJtpu1pKj5OMNZRe6g/yA6YOhEshJr+amF+bIA9FW7h+kC82cZPMHQpkCKs6m2s7iAKit/VX0c2Kc2e5z3CcGri1mhtnnDVRN+9ohpYbkmt6HJBvllXWQXqIQhDXT5DZT7UAM3RcyZs0hbwEWNMnhpx1sG/ih4wbw5c7EOsKWnHrmEZmzE8XD1ziuyZeW5hzi/xsQiUTHr7XnzRDxtbK+0ktCMFpc6sybFrs0VHw359R2DgpIBbjo9KL6Imk3zUbmYjWk68qaGiUmsNZ6B+zBI9JLQuPYY9KgvgvvaNt1RLSlryShaOgFC7rsMS/Lpjy0KLs5zR4fLQxSXkEUapty/SkkqzMjZghQd6pDVIKQwER1ep9miR70UVYL+Caswi9ElEHYgMWtbRVfYri9v+/C4vQAJI0M/jfa7b7XjfbL3ux300QBUH+mm6mhDb4ovMYlstvxBzJnfp2MMKtsoRKzZONJZSBZ4uAHePjh1zFOv6qBAwDbAzsenlprnOC5DB7rnjp5ya1Gn86pOjWzJFidULBGbC1br3nfWI3PEcX7IvwAIheqSdFSujUOlQNXNy7rnnqhJ6Eulo3IPZ/GjuBvnfB3ZFKVMaE4pf80lEYe9TvZRkZQ9rXnNQCWjpSYb5Djlva/Nh37fbGVjsFBV8nTudJnUduW26t30tNdQvlU1PAWF+9AOzbMqqKCRB+0Jz8ZmZg2kWj9mphr8IYRoah/FLMe3I4r2KX4rWJXQtEJYI+UJvUGyQCpgXMsKxNEmwKxmVeFRJcm1Yan+tLl+zu kV5mropi hoFLW0jWcrHdQ5MFE5FAhPeQ5txYUJiZk1l1rqLqE6ivQJwYlXnIZdj+1jKN3htVaVwAsfBFESkuREp9x+IaWdck5V/CGFfr4PPhQ1P9ycOwJBQJEp6F0QA0rFS/dH5OXv+CF+3xeU1SYePc8bXcgOfY/MOOZ8HJZ7zcbi+sCHuTP5Ge9s6IStmMxi7qRcVDdsNsvGVcWjPRn430= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Jul 26, 2024 at 09:46:18PM +1200, Barry Song wrote: > A user space interface can be implemented to select different swap-in > order policies, similar to the mTHP allocation order policy. We need > a distinct policy because the performance characteristics of memory > allocation differ significantly from those of swap-in. For example, > SSD read speeds can be much slower than memory allocation. With > policy selection, I believe we can implement mTHP swap-in for > non-SWAP_SYNCHRONOUS scenarios as well. However, users need to understand > the implications of their choices. I think that it's better to start > with at least always never. I believe that we will add auto in the > future to tune automatically, which can be used as default finally. I strongly disagree. Use the same sysctl as the other anonymous memory allocations.