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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF066CD6E7C for ; Fri, 5 Jun 2026 16:17:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4E9B36B00AC; Fri, 5 Jun 2026 12:17:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 49A506B00AE; Fri, 5 Jun 2026 12:17:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 362416B00AF; Fri, 5 Jun 2026 12:17:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 20FD26B00AC for ; Fri, 5 Jun 2026 12:17:41 -0400 (EDT) Received: from smtpin06.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id DC7641A01E3 for ; Fri, 5 Jun 2026 16:17:40 +0000 (UTC) X-FDA: 84846364680.06.EA65582 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf25.hostedemail.com (Postfix) with ESMTP id CFAC0A000C for ; Fri, 5 Jun 2026 16:17:38 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=THQlvgDe; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf25.hostedemail.com: domain of npache@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=npache@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1780676259; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=duJTZJog/IvaQNcYHxOllCKMt0JMc5PBsQeEuw3a1uk=; b=MyeP3bRwqNt4R9bR69CHj7I6bOZIOPkwB90jgi9omXV3Xr5KpQRQ83cjB3EB4wr61cXhNg HmdpO/A5HUB7Uvpp9fw07/Pg5ZQ6iIA7iKZ0UvT8vwjPqooLtwdpV4yOiukKZ5taBS6gCc w0rcqOcMOyihXmkuLhGWTfNl08TgZH4= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=THQlvgDe; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf25.hostedemail.com: domain of npache@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=npache@redhat.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1780676259; b=W8swe7tEHFKterbPc9YMUbFufdGD+P7M7/415X0bgPixEfQjRzH6eCBrp0+Dv9LB+vjm/E 9GLAQCLeEM6oIaLq45WWVm/VmiFH5zcd92/sWW9fQ3+pHDxkO1BbFvEfugznbtFMx0SRJz e2MEMW9owtQMx6KMtrh24ued4p6iNoA= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780676258; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=duJTZJog/IvaQNcYHxOllCKMt0JMc5PBsQeEuw3a1uk=; b=THQlvgDe3y5D6VFbfsEtMof8zK86dlqaxTSbID3mV425aDYhWhgX8vlwvJf//ukat4osZY deyS+NAS3nQkMi5YBoIOp8vkzRZKJ826LLFqxsctMOvaCqdpvXfH2Vx6+SuJJ3w/ZueqP9 +3+gm1zQz+o3Ms3DKv66Wlrj9oEdxNk= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-30-r2y2APjoNHm0hIHVBdBPqw-1; Fri, 05 Jun 2026 12:17:35 -0400 X-MC-Unique: r2y2APjoNHm0hIHVBdBPqw-1 X-Mimecast-MFC-AGG-ID: r2y2APjoNHm0hIHVBdBPqw_1780676250 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F40CA19560B6; Fri, 5 Jun 2026 16:17:29 +0000 (UTC) Received: from p1.redhat.com (unknown [10.44.22.9]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 36F2D1800351; Fri, 5 Jun 2026 16:17:11 +0000 (UTC) From: Nico Pache To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Cc: aarcange@redhat.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jack@suse.cz, jackmanb@google.com, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, liam@infradead.org, ljs@kernel.org, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, npache@redhat.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com, Usama Arif Subject: [PATCH mm-unstable v19 12/14] mm/khugepaged: avoid unnecessary mTHP collapse attempts Date: Fri, 5 Jun 2026 10:14:19 -0600 Message-ID: <20260605161422.213817-13-npache@redhat.com> In-Reply-To: <20260605161422.213817-1-npache@redhat.com> References: <20260605161422.213817-1-npache@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: s9dzvN7u_i38OwUdEwoYAvvzPjMfjH-vK4-Nbq5Jg0s_1780676250 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: CFAC0A000C X-Stat-Signature: gp85rksy5o8us51n4h8knb3p3fc9p6sr X-HE-Tag: 1780676258-384962 X-HE-Meta: U2FsdGVkX18FouV14xAuNMsMwERHzPd68lMCh6I/O1Anckqn+FTufFOACXhbCCGH9XdOckg2HokxVtUICxVi//UmO8aP17eB0YHixquDhsvshH9Qxkthw+IgVaOsdgws/kTs74DPW+lQ+EmfC61cWJCRPia7TYf6HEvMq7Mcrax2lYuHLO1/7FhEothon8K3LdtXVgWAyCS+86zWQk9/R0QBz1KhCr7YBvXzAox50gPT2+YI0PUKnQ0qfKMPTij5RklWAUOnhHRV/10OnBjD9bktTZbaCDddhb3ncZ6aiRgAGwM2qneWFwc8CUBe4P5ailLH7vrSdElTyespj1Fk5kpZvcGx/KkYwtYj3BP00+qGBLlSTvbRksDuN/R40wkiZqpW6Hoxt3ku3gq7rsLaJbO2YIhKgemYS84073ofTiLr7HeG9aoGggi5bXp3hzaoq/dWwm/oc0VCX98yxAYgrR9tqY1YwciRduOk2S2MlhzujBWS24Xkg3U6k4jywxxrKA26KsNjXMGvcVAaaPAnLCawEvhn4qyJiu4pAKnZkQJwNbHE4NdygcsOvQI3tk9kFrH/N/CZ2jgL1zPBHVeWHyMgXY1vAo84BEYlJx4CMUeq+rrL8LurhyIZAMQruga9hwwBiVtdfO3XiANkXcWXBHIYCZVHMrIhxtsK3kAMummfCgw4IElsd6gdPhjdE8BhfgABz8fP3By1Zd73DINS+UTH86r9xwzYnMj9cnuo0IDEqnDSpiJXJEhrAQM2SxFfCSZryW/h0T80InQyYsNuC8IYuHWVCypgj59LIYDtD16e/wXbumtWWti4ZLqLnTmO6hG4PA62mOzjp0pAi125PuC+3cSUgINYP8XB21kzqvTBuV3dAxlUT+VrGyrQ38gIHxszzBJlJ9lMP8cCCjUGTc7RgFXD40H2Q1mfk7HfNnWbU7r9TuLlw9CZRzVVDFP1o9pxom9TperdNeRKavk S0UbhlNu S1XxdKKEhMCR4n0gzUt+6j8qM9lcUPus3fseZ2GSCEBP8cND2d/QS+I8iGzC4EeHkUUfrSWzTZN1uhIVzjZOFB2Ud5eRaXXXhAjIKT9RA16SFTIe8OQ3GofFu7UypHJuXdNWnldgCtvS2N7xQvqgqYBclbvnkqYTSEGwJSCRqb+4baBPUP6s9TIhqWXZuRZABHFcOF1iqAvLB6M3u9LWuSLltal9AeeRONIFdIyhYST9DmByfmyr8WHN2NSpxAHBaPOR5iwxvrBqCewbI/U21hbG8cHSsp9OMp26is7RXRKkU1rS/GPzeUgTQFPaf+xbONJlc2tm4Bd3YkItFx/lgEvjcuBpYJ/jT3F6tQj0djhFNVJqEzTYcz/BH5dbpyTIQvDXzCNjnd29OVu3hfWfLUGcnApx7TXuDgImZC3HknZNgfnw19KWrJhzIjA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: There are cases where, if an attempted collapse fails, all subsequent orders are guaranteed to also fail. Avoid these collapse attempts by bailing out early. Reviewed-by: Lorenzo Stoakes Acked-by: Usama Arif Acked-by: David Hildenbrand (Arm) Signed-off-by: Nico Pache --- mm/khugepaged.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 430047316f43..7de92b28dd30 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1499,6 +1499,7 @@ static enum scan_result mthp_collapse(struct mm_struct *mm, collapse_address = address + offset * PAGE_SIZE; ret = collapse_huge_page(mm, collapse_address, referenced, unmapped, cc, order); + switch (ret) { /* Cases where we continue to next collapse candidate */ case SCAN_SUCCEED: @@ -1509,6 +1510,18 @@ static enum scan_result mthp_collapse(struct mm_struct *mm, /* Cases where lower orders might still succeed */ case SCAN_ALLOC_HUGE_PAGE_FAIL: alloc_failed = true; + fallthrough; + case SCAN_LACK_REFERENCED_PAGE: + case SCAN_EXCEED_NONE_PTE: + case SCAN_EXCEED_SWAP_PTE: + case SCAN_EXCEED_SHARED_PTE: + case SCAN_PAGE_LOCK: + case SCAN_PAGE_COUNT: + case SCAN_PAGE_NULL: + case SCAN_DEL_PAGE_LRU: + case SCAN_PTE_NON_PRESENT: + case SCAN_PTE_UFFD_WP: + case SCAN_PAGE_LAZYFREE: last_result = ret; goto next_order; /* Cases where no further collapse is possible */ -- 2.54.0