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Thu, 7 Aug 2025 06:37:35 GMT Received: from smtpav04.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1A31D581AE; Thu, 7 Aug 2025 06:37:35 +0000 (GMT) Received: from smtpav04.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AD192581A3; Thu, 7 Aug 2025 06:37:29 +0000 (GMT) Received: from [9.67.88.77] (unknown [9.67.88.77]) by smtpav04.wdc07v.mail.ibm.com (Postfix) with ESMTP; Thu, 7 Aug 2025 06:37:29 +0000 (GMT) Message-ID: <13be1ce2-85b5-46e2-aab8-94aa7f8a0cfe@linux.ibm.com> Date: Thu, 7 Aug 2025 12:07:27 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] sched/fair: Remove stale references to LAST_BUDDY and SKIP_BUDDY To: 20250314090128.25141-1-vineethr@linux.ibm.com, Peter Zijlstra , Ingo Molnar Cc: Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , LKML , Adam Li , Madadi Vineeth Reddy References: <20250314090128.25141-1-vineethr@linux.ibm.com> <4da6d43b-59f6-48e4-b58c-2f0792035851@linux.ibm.com> Content-Language: en-US From: Madadi Vineeth Reddy In-Reply-To: <4da6d43b-59f6-48e4-b58c-2f0792035851@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODA3MDA0NyBTYWx0ZWRfXzAQLRr5g8YcB azDlxagUzvgY2/ilgJPpjcajBlw0McGT0qkUwUArAb0ymKpuxXzVdNdDNbQO4DfoTuMzJVmC69y Sf1e/2NmbiHjS3VdQCzZDjum5G79MHucUJCGxhb5+DKhCP9iyPhpGKJ1AfFZIUld8VMpDRPWTYT 9Tu6z7yisXSfLnvAf0McxDLZkhXvt3it8XC7KtSar1BJOiDFGbVR+OajBiZ+w7Ci/Fi0fhgRpws DQE8B2CRQdryl8k8mis/7Y0fjlf0bhGAlsufcv0P98n1J2H5XlyIaWk3v4ak1gbpU8tkf6m6UBL PeF17eslyQLVB9O02eLfhNqhroWAPub1DLbAY/J+qzTp6Javf33io+SxgOVj/ap2Idyvr92CJ1i w1nXnaUnTE5Sv97VV/bX4FiM6By8NvDlHXzjzDSet9KMjwCCoRyfw5+DvF75n0fxMzEanUUw X-Proofpoint-GUID: UMOkaenvapBH4qSNnJPOd9d07qYQJNv2 X-Authority-Analysis: v=2.4 cv=BIuzrEQG c=1 sm=1 tr=0 ts=689449b3 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=2OwXVqhp2XgA:10 a=vzhER2c_AAAA:8 a=VnNF1IyMAAAA:8 a=ITTc_KzUxks3pkYUosUA:9 a=QEXdDO2ut3YA:10 a=0YTRHmU2iG2pZC6F1fw2:22 X-Proofpoint-ORIG-GUID: yCfuYDoR0q0r-vLeIjOIP1qTe7m4M3Ax X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-06_05,2025-08-06_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 impostorscore=0 priorityscore=1501 lowpriorityscore=0 suspectscore=0 spamscore=0 mlxlogscore=999 adultscore=0 clxscore=1015 malwarescore=0 phishscore=0 bulkscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2508070047 On 13/04/25 09:40, Madadi Vineeth Reddy wrote: > Hi Peter, Ingo, > > Ping. > > Any thoughts on this? Can it be picked up? > > Thanks, > Madadi Vineeth Reddy Hi Peter, Ingo, This still applies cleanly on top of tip/sched/core. Could this be considered for merging? Thank you, Madadi Vineeth Reddy > > On 14/03/25 14:31, Madadi Vineeth Reddy wrote: >> Commit 5e963f2bd465 ("sched/fair: Commit to EEVDF") removed the >> functionality associated with LAST_BUDDY and SKIP_BUDDY. However, >> some outdated references remained in the comments for pick_next_entity >> and check_preempt_wakeup_fair. This commit cleans up those comments >> to maintain clarity and correctness. >> >> No functional change intended. >> >> Co-developed-by: Adam Li >> Signed-off-by: Adam Li >> Signed-off-by: Madadi Vineeth Reddy >> --- >> kernel/sched/fair.c | 6 +----- >> 1 file changed, 1 insertion(+), 5 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 9dafb374d76d..379dbcbb24e9 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -5578,8 +5578,6 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags); >> * Pick the next process, keeping these things in mind, in this order: >> * 1) keep things fair between processes/task groups >> * 2) pick the "next" process, since someone really wants that to run >> - * 3) pick the "last" process, for cache locality >> - * 4) do not run the "skip" process, if something else is available >> */ >> static struct sched_entity * >> pick_next_entity(struct rq *rq, struct cfs_rq *cfs_rq) >> @@ -8780,9 +8778,7 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int >> * >> * Note: this also catches the edge-case of curr being in a throttled >> * group (e.g. via set_curr_task), since update_curr() (in the >> - * enqueue of curr) will have resulted in resched being set. This >> - * prevents us from potentially nominating it as a false LAST_BUDDY >> - * below. >> + * enqueue of curr) will have resulted in resched being set. >> */ >> if (test_tsk_need_resched(rq->curr)) >> return; >