From nobody Wed Oct 8 07:06:36 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 6ACE61A2C04 for ; Wed, 2 Jul 2025 06:00:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751436059; cv=none; b=WvGntwh38smK6T716BPFWIdrcj+7ROPxczEYAUIPeCt73qiBH+hX+eW9+eLFQ4+xoMUpEsgqDRXJdpB+I7oAE6n3wDH8V668gefBvjiKQrtD+oe1jfrCI6Q27Qm3aR5W0ato8iNW0vCYhnlB7rTuD2HfD45y2y9MQFlaDMjKWbc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751436059; c=relaxed/simple; bh=4gUo5mhAQoIRF3zDizyxmkFzfYyi85yyGqjfCEGTlIk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ag83A58VWFNmrr5g9bYW4+cI+SP/XvAiwhH4E0QwaRG+dYp9fG1KFXbT7p/pPuKur3DWdZCtFKWTEz/ZnEWUnCP0gKDAwv+bd7zZH3c+E0dBVOXjOuZFJVjIY//y1YPGZCTPEmtoAd0xetXFpbbhkDTUN7QofTQFeiMUCYjpWM4= 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=UJ4bxkv1; arc=none smtp.client-ip=170.10.133.124 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="UJ4bxkv1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1751436055; 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=hlMD3t7ycJKRomUVuQAiuk5BAoj5s4ukulb+cMLGP2s=; b=UJ4bxkv1mq7BB2B0GuTSK+8j5/A3NhlupAtbUetnBtscJVxW/YRJGAnWDmwW6LkPfAm0bt NEz43u+6YftnbMqfUp0lrXOSdAhqqy5fZvYgmEM77tKaHcsxQupxagIugYkZCP3LejKm6/ B0wWGoIgOcSxO0JUvnVGIsDWp+24x94= 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-600-cY2WhJ9yNnWCB4gRyLU_-g-1; Wed, 02 Jul 2025 02:00:53 -0400 X-MC-Unique: cY2WhJ9yNnWCB4gRyLU_-g-1 X-Mimecast-MFC-AGG-ID: cY2WhJ9yNnWCB4gRyLU_-g_1751436048 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 4E0671955EC3; Wed, 2 Jul 2025 06:00:48 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.88.112]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C9E7A180045B; Wed, 2 Jul 2025 06:00:32 +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 Subject: [PATCH v8 09/15] khugepaged: avoid unnecessary mTHP collapse attempts Date: Tue, 1 Jul 2025 23:57:36 -0600 Message-ID: <20250702055742.102808-10-npache@redhat.com> In-Reply-To: <20250702055742.102808-1-npache@redhat.com> References: <20250702055742.102808-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" 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 61d2b3ebc7ac..50e1d7ef7e6d 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1358,6 +1358,23 @@ static int khugepaged_scan_bitmap(struct mm_struct *= mm, unsigned long address, collapsed +=3D (1 << order); continue; } + /* + * Some ret values indicate all lower order will also + * fail, dont trying to collapse smaller orders + */ + if (ret =3D=3D SCAN_EXCEED_NONE_PTE || + ret =3D=3D SCAN_EXCEED_SWAP_PTE || + ret =3D=3D SCAN_EXCEED_SHARED_PTE || + ret =3D=3D SCAN_PTE_NON_PRESENT || + ret =3D=3D SCAN_PTE_UFFD_WP || + ret =3D=3D SCAN_ALLOC_HUGE_PAGE_FAIL || + ret =3D=3D SCAN_CGROUP_CHARGE_FAIL || + ret =3D=3D SCAN_COPY_MC || + ret =3D=3D SCAN_PAGE_LOCK || + ret =3D=3D SCAN_PAGE_COUNT) + goto next; + else + break; } =20 next: --=20 2.49.0