From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6DDD5C43334 for ; Mon, 27 Jun 2022 12:31:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236136AbiF0Mbq (ORCPT ); Mon, 27 Jun 2022 08:31:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235685AbiF0Mba (ORCPT ); Mon, 27 Jun 2022 08:31:30 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79922DED1; Mon, 27 Jun 2022 05:31:29 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 23B0F21CE4; Mon, 27 Jun 2022 12:31:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1656333088; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=H2x18KoFRy5eal2D3ylc2+U1rybp7813ga/wOUoNe6s=; b=MN+FbeFBztRg1vQn/aZS6WgzpJcvWE6GlhrAy1Bn2uYz6Fgk3nG1G2IBxSamszzE041LHN FYiV/4Oov7dyHxK7Ap2HTWMY4KowzOrjMf2zZGO5NgGZfnmfaD9ie3tBC7hiO/8eBkBjto EEejyW10KiaUFmPLEkSEZ9i8fEwxLpw= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 87FAA2C141; Mon, 27 Jun 2022 12:31:27 +0000 (UTC) Date: Mon, 27 Jun 2022 14:31:27 +0200 From: Michal Hocko To: Yosry Ahmed Cc: Shakeel Butt , Johannes Weiner , Roman Gushchin , Muchun Song , Andrew Morton , Matthew Wilcox , Vlastimil Babka , David Hildenbrand , Miaohe Lin , NeilBrown , Alistair Popple , Suren Baghdasaryan , Peter Xu , Linux Kernel Mailing List , Cgroups , Linux-MM Subject: Re: [PATCH] mm: vmpressure: don't count userspace-induced reclaim as memory pressure Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 27-06-22 02:39:49, Yosry Ahmed wrote: [...] > (a) Do not count vmpressure for mem_cgroup_resize_max() and > mem_cgroup_force_empty() in v1. yes, unless you have a very good reason to change that. E.g. this has been buggy and we have finally understood that. But I do not see any indications so far. > (b) Do not count vmpressure (consequently, > mem_cgroup_under_socket_pressure()) in v2 where psi is not counted > (writing to memory.max, memory.high, and memory.reclaim). I can see clear arguments for memory.reclaim opt out for vmpressure because we have established that this is not a measure to express a memory pressure on the cgroup. Max/High are less clear to me, TBH. I do understand reasoning for PSI exclusion because considering the calling process to be stalled and non-productive is misleading. It just does its work so in a way it is a productive time in the end. For the vmpressure, which measures how hard/easy it is to reclaim memory why this should special for this particular reclaim? Again, an explanation of the effect on the socket pressure could give a better picture. Say that I somebody reduces the limit (hard/high) and it takes quite some effort to shrink the consumption down. Should the networking layer react to that in any way or should it wait for the active allocation during that process to find that out? -- Michal Hocko SUSE Labs