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Wed, 04 Nov 2026 01:59:22 +0000 X-Mizu-Trace-ID: 8f7e9dda1911563a X-Migadu-Flow: FLOW_OUT Date: Tue, 3 Nov 2026 17:59:11 -0800 From: Shakeel Butt To: Dave Hansen Cc: "Ababneh, Ehab" , Barry Song , Johannes Weiner , "ziy@nvidia.com" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "buddy.lumpkin@oracle.com" , "akpm@linux-foundation.org" , "kasong@tencent.com" , "qi.zheng@linux.dev" , "axelrasmussen@google.com" , "yuanchu@google.com" , "weixugc@google.com" , "david@kernel.org" , "ljs@kernel.org" , "liam@infradead.org" , "vbabka@kernel.org" , "rppt@kernel.org" , "surenb@google.com" , "mhocko@suse.com" , "jackmanb@google.com" , "baoquan.he@linux.dev" , "baolin.wang@linux.alibaba.com" Subject: Re: [RFC PATCH v2 0/5] mm/vmscan: adaptive multi-threaded kswapd for NUMA-aware reclaim Message-ID: <20261104015214.GA1088663@shakeel.butt@linux.dev> References: X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 4589480004 X-Spam-Status: No, score=-4.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MSGID_MULTIPLE_AT,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Stat-Signature: dk1ourncyabfo9q9oyespht5mij8zsmj X-HE-Tag: 1793757567-117272 X-HE-Meta: U2FsdGVkX181c1aMrS+1Zm4UruE+rhHIOryyJ9A8PYyV16aQmyC5FLXMLFCVSDJO2tKOHaCKfTjQORSk5ZqCnw8Pq+Vof1ywxKWOlt06ezDp5N7QthMbiKjSx9Y53bXK4o0CXKklcgXm2oX1siTvVKXS6rrvW7Drhi88/JJv/bmNP4g4VfrTfeejYEw2aFR7ZpXDgi/nxAcrNeL0PmnDfYIPXcrF7xsx+r0zxiyMLHEwrUmPnAHR90IG17PB6+qfDAGUHUm2u6WzbYKdB+EiZtQgIhSN5k18x34iqqTVwFC1GPS//vnfX7UwAgxzrTGi1675r+7gf1lzgyyXMMy3WIBQLYDOGGIatLKSpA1XHRiFD6lbWEGdEPHVWZMSOAKbeCWL/NSmBFWHiSP1qP/aE81MEcWAt4iu8O6U5Gl1I/8UQG8CN7xPk9Q/aX9iqFfz8P46988jdTC5eaQcZmJ9/VAsfP+N4ifCPNs+vAx+d+4gKij0jhdL8HqSpluh/Z3b1v4SIkQjW4uB5PeOCkpq/GV6TVJ+HdSIBeCO3rQLmr+/XjxzIXLfGE5GXl7qmm/G3Z/7DLrVfhiPyq9gh1KQuoA3ch5ZInx+Hwa9B2O/LkxWB0T5iS8kYYVVfkjq5ytx4VbdcKSqJYLopyur5ETAIQWC3OJ34/SL+LxLF5dlOrAEJVTI83YskxiZig1MeaDn1R7eTJ3Ex89nUTfxR0inS3ni7zlcUlLoak8rXnAH+WrBMeQeeMFdWCGi3f8BB1l1kREmJzvrXXlD0ketK3a20hB3WpQLQ7recKh2n8LhmwpqjqXaFJ4BnIJdgcjf4Uy9+vVSQT9o4E25Li2ZdmnvOdddsEzVPv3tREcqZ4BVu6GDlYduK8t2KWnO9F6Cs8enGUwDjfKyDd73mNExQZb4ilA3hsybj/0ov2lBUaJBrdFporEdr5HfSgxxBG3ILZV65vPMzRVOzg/GK1031Ox 5MDIOkaj tC69HcFrgWt4Tm0oGD4hN1nxmHtOZVpzfFz0Sn9m8jE5h64UdxZuNgFOxxucR3OjAw6uZHz4sffzHSA6p4USZNSYGcOLXYpsUR066f8r7qf78nbkH/i/4VDGnsxamVTm8tezs7WxUtxflon6OttbZodce0+8SKbcKc/qBRuxQIzCwgTRhK6zGSWj+AAizdbRpm8cL3WqkQMvOwXTxXhgxvk1Dl9SsA57j1vE2q7LCIX2yoLtsf7Giu8ylgBWxH/W/m9iH1ysFXjKKcwix1vy+IOWnpuVQv2zfkI9SwAJTNgZy+GSCwqHKfT+nzg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Nov 03, 2026 at 04:15:44PM -0800, Dave Hansen wrote: > On 11/3/26 15:41, Ababneh, Ehab wrote: > > I would appreciate your thoughts on how we might achieve a similar > > performance improvement without increasing the number of kswapd > > threads. > > It also just plain doesn't seem like folks are very interested in > optimizations in this area at the moment. Feedback that's basically, "go > optimize something else" would also be very welcome. Hi Ehab and Dave, My appologies for late response. I have not gotten the chance to look deeper into the series as I am stuck in something else but I am very much interested in this (line of) work. I have discussed with Johannes about multithreaded kswapds but the motivation is more about scaling kswapd threads corresponding to the number of cores on the node. We are getting CPU with hundred of cores per numa code and kswapd is already too late or slow to keep up with allocations happening on all of those cores. So, I definitely think we need multiple workers doing the background reclaim. Please give me sometime, I will organize my thoughts on how we should aim to tackle this challenge. I will also ask Johannes to provide his take on the issue. Thanks for pushing this work. Shakeel