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 E4B9EC433EF for ; Thu, 23 Jun 2022 00:16:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241624AbiFWAQ4 (ORCPT ); Wed, 22 Jun 2022 20:16:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229483AbiFWAQx (ORCPT ); Wed, 22 Jun 2022 20:16:53 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1CE23DDE5; Wed, 22 Jun 2022 17:16:50 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 57788B82049; Thu, 23 Jun 2022 00:16:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F72EC34114; Thu, 23 Jun 2022 00:16:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1655943408; bh=0HHOSMhVBBKa0mo1Ox4swwAng7m4PNBNQ15WTnWPLgs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=uffvUBvnICh3cunCqu0zSZ1OAiv7ZIIt1RMEKeKs8/4hNLKU03og4Wofr+bZS4Sm1 d74wVtvf2ahSh8kTJYA5ooQeLQUProiI6/f9Us2iMab2lApNEOpHbnhAY3MmfamYb5 EIf6KaSw1DitFZCIrHU3wrQ897oXGvxQPVC783OU= Date: Wed, 22 Jun 2022 17:16:24 -0700 From: Andrew Morton To: Yosry Ahmed Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Matthew Wilcox , Vlastimil Babka , David Hildenbrand , Miaohe Lin , NeilBrown , Alistair Popple , Suren Baghdasaryan , Peter Xu , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm: vmpressure: don't count userspace-induced reclaim as memory pressure Message-Id: <20220622171624.fc7de8d0ab18a5cf663f8ab8@linux-foundation.org> In-Reply-To: <20220623000530.1194226-1-yosryahmed@google.com> References: <20220623000530.1194226-1-yosryahmed@google.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Jun 2022 00:05:30 +0000 Yosry Ahmed wrote: > Commit e22c6ed90aa9 ("mm: memcontrol: don't count limit-setting reclaim > as memory pressure") made sure that memory reclaim that is induced by > userspace (limit-setting, proactive reclaim, ..) is not counted as > memory pressure for the purposes of psi. > > Instead of counting psi inside try_to_free_mem_cgroup_pages(), callers > from try_charge() and reclaim_high() wrap the call to > try_to_free_mem_cgroup_pages() with psi handlers. > > However, vmpressure is still counted in these cases where reclaim is > directly induced by userspace. This patch makes sure vmpressure is not > counted in those operations, in the same way as psi. Since vmpressure > calls need to happen deeper within the reclaim path, the same approach > could not be followed. Hence, a new "controlled" flag is added to struct > scan_control to flag a reclaim operation that is controlled by > userspace. This flag is set by limit-setting and proactive reclaim > operations, and is used to count vmpressure correctly. > > To prevent future divergence of psi and vmpressure, commit e22c6ed90aa9 > ("mm: memcontrol: don't count limit-setting reclaim as memory pressure") > is effectively reverted and the same flag is used to control psi as > well. I'll await reviewer input on this, but I can always do trivia! > @@ -3502,6 +3497,8 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, > static int mem_cgroup_force_empty(struct mem_cgroup *memcg) > { > int nr_retries = MAX_RECLAIM_RETRIES; > + unsigned int reclaim_options = MEMCG_RECLAIM_CONTROLLED | > + MEMCG_RECLAIM_MAY_SWAP; If it doesn't fit, it's nicer to do unsigned int reclaim_options; ... reclaim_options = MEMCG_RECLAIM_CONTROLLED | MEMCG_RECLAIM_MAY_SWAP; (several places) > @@ -3751,6 +3757,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order, > .may_writepage = !laptop_mode, > .may_unmap = 1, > .may_swap = 1, > + .controlled = 0, > }; Let's just skip all these initializations to zero, let the compiler take care of it. > @@ -4095,6 +4112,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int highest_zoneidx) > .gfp_mask = GFP_KERNEL, > .order = order, > .may_unmap = 1, > + .controlled = 0, > }; > > set_task_reclaim_state(current, &sc.reclaim_state); > @@ -4555,6 +4573,7 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim) > .may_unmap = 1, > .may_swap = 1, > .hibernation_mode = 1, > + .controlled = 0, > }; > struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask); > unsigned long nr_reclaimed; > @@ -4707,6 +4726,7 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in > .may_unmap = !!(node_reclaim_mode & RECLAIM_UNMAP), > .may_swap = 1, > .reclaim_idx = gfp_zone(gfp_mask), > + .controlled = 0, > }; > unsigned long pflags;