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Mon, 8 Aug 2022 06:27:06 +0000 (GMT) Received: from skywalker.ibmuc.com (unknown [9.43.19.76]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTP; Mon, 8 Aug 2022 06:27:06 +0000 (GMT) From: "Aneesh Kumar K.V" To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: Wei Xu , Huang Ying , Yang Shi , Davidlohr Bueso , Tim C Chen , Michal Hocko , Linux Kernel Mailing List , Hesham Almatary , Dave Hansen , Jonathan Cameron , Alistair Popple , Dan Williams , Johannes Weiner , jvgediya.oss@gmail.com, "Aneesh Kumar K.V" Subject: [PATCH v13 9/9] lib/nodemask: Optimize node_random for nodemask with single NUMA node Date: Mon, 8 Aug 2022 11:56:01 +0530 Message-Id: <20220808062601.836025-10-aneesh.kumar@linux.ibm.com> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220808062601.836025-1-aneesh.kumar@linux.ibm.com> References: <20220808062601.836025-1-aneesh.kumar@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-GUID: t1KZaO_Yul7vT8aqZ_tnU9bCL67z8lYx X-Proofpoint-ORIG-GUID: qk0acrlX4inmpnQSAoP_SET7g4Q8bi1Y X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-08-08_03,2022-08-05_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 adultscore=0 priorityscore=1501 phishscore=0 suspectscore=0 bulkscore=0 mlxlogscore=999 lowpriorityscore=0 impostorscore=0 clxscore=1015 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2206140000 definitions=main-2208080031 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The most common case for certain node_random usage (demotion nodemask) is w= ith nodemask weight 1. We can avoid calling get_random_init() in that case and always return the only node set in the nodemask. Signed-off-by: Aneesh Kumar K.V --- lib/nodemask.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/lib/nodemask.c b/lib/nodemask.c index e22647f5181b..c91a6b0404a5 100644 --- a/lib/nodemask.c +++ b/lib/nodemask.c @@ -20,12 +20,21 @@ EXPORT_SYMBOL(__next_node_in); */ int node_random(const nodemask_t *maskp) { - int w, bit =3D NUMA_NO_NODE; + int w, bit; =20 w =3D nodes_weight(*maskp); - if (w) + switch (w) { + case 0: + bit =3D NUMA_NO_NODE; + break; + case 1: + bit =3D __first_node(maskp); + break; + default: bit =3D bitmap_ord_to_pos(maskp->bits, - get_random_int() % w, MAX_NUMNODES); + get_random_int() % w, MAX_NUMNODES); + break; + } return bit; } #endif --=20 2.37.1