From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F78363CB for ; Mon, 14 Jul 2025 00:34:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752453297; cv=none; b=ndeU3H/eszf0TQczv26erltGyRNDyG9Z7J2chqidPhwrxg98CjQrRZ4NSVg41J7lwyWcsBkA4GAxvQ3Es5Y/MAejnXouxrFe7ZhzGh3qYPCxNpMJxrwu2qSpSnKFXVPZRnqhf2O3PQjWNvA5G1R6fdThARvhdQWbGZYo8zrpya8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752453297; c=relaxed/simple; bh=APLURJLlYBirxrIp/mY7RmU7pUPhLVo8iELDJJ4+8oo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IcXCUpEtEe7AThmkz9oTF4XoTwdbAFO+SRyuH3JTc+wH+/JLXu9bh/DEclN/HDbc+5YrINNhIDJLjfPcYugq2VUsuq52Ykf1tLkmBRSvwM04dPxyeOcqGup6B/EUI/8M9WiZBdtPg7wj2QMMjJCSPpJG9RJ4LnGhubDLqSrYF7U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=eRdxeIAU; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eRdxeIAU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752453295; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BfZNAwhk1NqT5tIuPPyjI7C606wcPsYsghkwk2GurVA=; b=eRdxeIAURhL1wL7QW6hPw4KjH+mZEUkGEhkRXM/gH61ev85/g/YEakkuB1NXL0bPBU9f6j NxpLeJVnfaQVNbTMNqT69BdTs65j+bJkdHnU912o2xuWbXi88C0YhbX2XTRLQE4tk/4tu1 m9Xca9Yn5DrNSc2wOMngKbd0azGen2k= Received: from mx-prod-mc-02.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-653-FlwQt_DJNyqxL5eDISseBg-1; Sun, 13 Jul 2025 20:34:52 -0400 X-MC-Unique: FlwQt_DJNyqxL5eDISseBg-1 X-Mimecast-MFC-AGG-ID: FlwQt_DJNyqxL5eDISseBg_1752453288 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EF258195605A; Mon, 14 Jul 2025 00:34:47 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.64.9]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C570930001A1; Mon, 14 Jul 2025 00:34:34 +0000 (UTC) From: Nico Pache To: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: david@redhat.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, ryan.roberts@arm.com, dev.jain@arm.com, corbet@lwn.net, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, akpm@linux-foundation.org, baohua@kernel.org, willy@infradead.org, peterx@redhat.com, wangkefeng.wang@huawei.com, usamaarif642@gmail.com, sunnanyong@huawei.com, vishal.moola@gmail.com, thomas.hellstrom@linux.intel.com, yang@os.amperecomputing.com, kirill.shutemov@linux.intel.com, aarcange@redhat.com, raquini@redhat.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, tiwai@suse.de, will@kernel.org, dave.hansen@linux.intel.com, jack@suse.cz, cl@gentwo.org, jglisse@google.com, surenb@google.com, zokeefe@google.com, hannes@cmpxchg.org, rientjes@google.com, mhocko@suse.com, rdunlap@infradead.org, hughd@google.com Subject: [PATCH v9 09/14] khugepaged: avoid unnecessary mTHP collapse attempts Date: Sun, 13 Jul 2025 18:32:02 -0600 Message-ID: <20250714003207.113275-10-npache@redhat.com> In-Reply-To: <20250714003207.113275-1-npache@redhat.com> References: <20250714003207.113275-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 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. Signed-off-by: Nico Pache --- mm/khugepaged.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index a701d9f0f158..7a9c4edf0e23 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1367,6 +1367,23 @@ static int collapse_scan_bitmap(struct mm_struct *mm, unsigned long address, collapsed += (1 << order); continue; } + /* + * Some ret values indicate all lower order will also + * fail, dont trying to collapse smaller orders + */ + if (ret == SCAN_EXCEED_NONE_PTE || + ret == SCAN_EXCEED_SWAP_PTE || + ret == SCAN_EXCEED_SHARED_PTE || + ret == SCAN_PTE_NON_PRESENT || + ret == SCAN_PTE_UFFD_WP || + ret == SCAN_ALLOC_HUGE_PAGE_FAIL || + ret == SCAN_CGROUP_CHARGE_FAIL || + ret == SCAN_COPY_MC || + ret == SCAN_PAGE_LOCK || + ret == SCAN_PAGE_COUNT) + goto next; + else + break; } next: -- 2.50.0