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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AD09DC61DA3 for ; Fri, 24 Feb 2023 12:48:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=7l+P50ZyHmo+HGuV6w61T4DvRJ25qins6iidgiqcgqU=; b=vSa5dTIWrM5bfz yScYrnqX6GJfSK35ZARwA5/xPZ4DyXcb9cOdH4r8NqHZ/7Ep8ujbSX5/dfjB8D0FXuyYCp/t91Be9 kqTkq87/AtzuQDBcjCfFjIgEpg7JhLFBAGR97xp8r4yhKHfhcZ9XhtoBj3raL76SBsKE+c0L3fAs+ vVsxERIrvJ3mJOGMhO7Aqx64OEAwx89WhOo/VcDE0VeXqrqwaHdTgJkW17jAE8uulvqZUbo+0Y0iu NiP99iYuT17jeaeiqmZ+ybSB2ozh/16nwR0w72tSO3VfLHzzkP4p1Kjz4V+Kegou/bWNcDljTiJPi K4WokoLF5OwA2Fc/HmGA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pVXUE-002SiP-Rn; Fri, 24 Feb 2023 12:47:42 +0000 Received: from smtp-out1.suse.de ([195.135.220.28]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pVXUC-002Sgo-1H for linux-arm-kernel@lists.infradead.org; Fri, 24 Feb 2023 12:47:41 +0000 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 9E51F38C9E; Fri, 24 Feb 2023 12:47:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1677242856; 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=FRS6JIVxD98UMfKKQQi4U8ooVdVzZHO1t/2LZ6jiUFs=; b=r3ur6fxcW92yEcWBOA6q76sBEhcOGqHa26Ze7DErSHeh+g0UKez4w4NTMAH1baJ9s0s49f xTKXrXS5ST25dtnvUjd6jghioSjnLxf+zZMwu6tYOw+ri2WBg+7UF2viOdwlud9VBybt96 vFWJK8WI8B5vjik2Bzm3Fp1IyCm1aI4= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 8174D13A3A; Fri, 24 Feb 2023 12:47:36 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id K39AHOix+GOELwAAMHmgww (envelope-from ); Fri, 24 Feb 2023 12:47:36 +0000 Date: Fri, 24 Feb 2023 13:47:35 +0100 From: Michal Hocko To: Suren Baghdasaryan Cc: Sudarshan Rajagopalan , David Hildenbrand , Johannes Weiner , Mike Rapoport , Oscar Salvador , Anshuman Khandual , mark.rutland@arm.com, will@kernel.org, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, Trilok Soni , Sukadev Bhattiprolu , Srivatsa Vaddagiri , Patrick Daly Subject: Re: [PATCH] psi: reduce min window size to 50ms Message-ID: References: <15cd8816-b474-0535-d854-41982d3bbe5c@quicinc.com> <82406da2-799e-f0b4-bce0-7d47486030d4@quicinc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230224_044740_267782_295896C9 X-CRM114-Status: GOOD ( 12.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue 14-02-23 11:34:30, Suren Baghdasaryan wrote: [...] > Your suggestion to have this limit configurable sounds like obvious > solution. I would like to get some opinions from other maintainers. > Johannes, WDYT? CC'ing Michal to chime in as well since this is mostly > related to memory stalls. I do not think that making this configurable helps much. Many users will be bound to distribution config and also it would be hard to experiment with a recompile cycle every time. This seems just too impractical. Is there any reason why we shouldn't allow any timeout? Shorter timeouts could be restricted to a priviledged context to avoid an easy way to swamp system by too frequent polling. Btw. it seems that there is is only a limit on a single trigger per fd but no limits per user so it doesn't sound too hard to end up with too much polling even with a larger timeouts. To me it seems like we need to contain the polling thread to be bound by the cpu controller. -- Michal Hocko SUSE Labs _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel