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b=DtTvGZNLaaVcGJ7CqYXJdkcLABrxmaouQKpPQ7NvFPJm3ClWqz2fv+4C5VmW45wKk o48p+PWxpBuuwrvAGk/xIb//Ecztd6FXj767haIoAzIUXxQ1VAFpZaPVKIdzoHBh0r 6HEc0P0qBJxx3hO4Wi8S8GsvVFZZtAZMhL8307OHFnZZ6ro/5+ABtZiJer6Dew5Si/ n4IGzeK0Ym3HCm26fgntGYCVHxLhhnOYHLzuA77T+R+KbQZca05KFhn5c6R2+nw/lA A+a1WxbI9IilwIzkYvEqzV7QE2wYEOZnJkYInHLWU9XTj8ZhMEBhc27KNDMmorW0D6 pJaEY30em6g+A== Date: Fri, 3 Apr 2026 13:49:50 -0700 From: Jakub Kicinski To: "JP Kobryn (Meta)" Cc: linux-mm@kvack.org, willy@infradead.org, hannes@cmpxchg.org, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, riel@surriel.com, edumazet@google.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH v2] mm/vmpressure: skip socket pressure for costly order reclaim Message-ID: <20260403134950.3af8b4f5@kernel.org> In-Reply-To: <20260402232511.17246-1-jp.kobryn@linux.dev> References: <20260402232511.17246-1-jp.kobryn@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 16F2DC0006 X-Stat-Signature: kcn6i4dz1kk9jth7w8n1zp6371ccza1r X-HE-Tag: 1775249392-292251 X-HE-Meta: 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 k2PviJdJ qCQuIjmdJ0rl8QTZVKn5GK236JqGu2SSePFz0+C4RRaa5ruEBjQyuIHh8Ex/+YcV97EX1gQyDZ0QsXK/bl+kfFzflGSgrkbUf6WGAnpzx+cWzYx4w10uAPh77AbgoxHIQM+dabNx4nKFWSdsLT//RVxyfvHP+m+D9JXmlLGo/Xtx9Lo8+8p5iPWrLYg+r4VjikY7gz1MSy0Eqk9X1wFgag2pd8Tw94l1mYOrFb/58dFDfMANX4fCCoY43Zwtzvb5itDibS8rpg6ZIh28LBWOHHqENig== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 2 Apr 2026 16:25:11 -0700 JP Kobryn (Meta) wrote: > When kswapd reclaims at high order due to fragmentation, vmpressure() can > report poor reclaim efficiency even though the system has plenty of free > memory. This is because kswapd scans many pages but finds little to reclaim > - the pages are actively in use and don't need to be freed. The resulting > scan:reclaim ratio triggers socket pressure, throttling TCP throughput > unnecessarily. Acked-by: Jakub Kicinski FWIW