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Tue, 10 Nov 2026 05:25:39 -0800 (PST) Received: from [192.168.1.22] ([83.231.69.9]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4ba0203a76esm55864295e9.3.2026.11.10.05.25.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Nov 2026 05:25:38 -0800 (PST) Message-ID: <057dc7a4-cdf6-48dd-b326-49c92a936b9b@gmail.com> Date: Tue, 10 Nov 2026 14:25:37 +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] mm, vmscan: make kswapd unreserve highatomic pageblocks To: "Vlastimil Babka (SUSE)" , Johannes Weiner Cc: Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Zi Yan , David Hildenbrand , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , JP Kobryn , Frank van der Linden , Thadeu Lima de Souza Cascardo , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20261109-kswapd-highatomic-unreserve-v2-1-6587ca75c77f@kernel.org> Content-Language: en-US From: "Jose A. Perez de Azpillaga" In-Reply-To: <20261109-kswapd-highatomic-unreserve-v2-1-6587ca75c77f@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/9/26 11:20 AM, Vlastimil Babka (SUSE) wrote: [snip] > Hook this highatomic unreserve to the moment we exit the loop in > balance_pgdat() due to exhausting reclaim priority, which means pgdat > was not balanced and the last kswapd_shrink_node() attempt returned > false or failed to reclaim anything. Even if that last attempt made the > pgdat balanced, kswapd was struggling enough, so unreserving is far from > premature. This should be a more conservative variant of when direct > reclaim failure triggers the unreserving. Pass force as true to make > sure repeated failures fully unreserve everything. Also make sure we > don't count kswapd failures until then. Don't restart immediately as > the kswapd() loop will call balance_pgdat() again if the unreserve does > not lead to a balanced pgdat. > the lowest priority gating looks good to me. however, sashiko found some concerns [1]. [1]: https://sashiko.dev/#/patchset/20261109-kswapd-highatomic-unreserve-v2-1-6587ca75c77f%40kernel.org -- cheers, jose a. p-a