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From: Tejun Heo <tj@kernel.org>
To: David Vernet <void@manifault.com>,
	Andrea Righi <arighi@nvidia.com>,
	Changwoo Min <changwoo@igalia.com>
Cc: linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev,
	Tejun Heo <tj@kernel.org>
Subject: [PATCH 1/7] sched_ext: Use rhashtable_lookup() instead of rhashtable_lookup_fast()
Date: Sun, 21 Sep 2025 15:32:40 -1000	[thread overview]
Message-ID: <20250922013246.275031-1-tj@kernel.org> (raw)

The find_user_dsq() function is called from contexts that are already
under RCU read lock protection. Switch from rhashtable_lookup_fast() to
rhashtable_lookup() to avoid redundant RCU locking.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 kernel/sched/ext.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index f5873f8ed669..df433f6fab4b 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -207,7 +207,7 @@ static struct scx_dispatch_q *find_global_dsq(struct task_struct *p)
 
 static struct scx_dispatch_q *find_user_dsq(struct scx_sched *sch, u64 dsq_id)
 {
-	return rhashtable_lookup_fast(&sch->dsq_hash, &dsq_id, dsq_hash_params);
+	return rhashtable_lookup(&sch->dsq_hash, &dsq_id, dsq_hash_params);
 }
 
 /*
-- 
2.51.0


             reply	other threads:[~2025-09-22  1:32 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-22  1:32 Tejun Heo [this message]
2025-09-22  1:32 ` [PATCH 2/7] sched_ext: Improve SCX_KF_DISPATCH comment Tejun Heo
2025-09-23  7:20   ` Andrea Righi
2025-09-22  1:32 ` [PATCH 3/7] sched_ext: Fix stray scx_root usage in task_can_run_on_remote_rq() Tejun Heo
2025-09-23  7:22   ` Andrea Righi
2025-09-22  1:32 ` [PATCH 4/7] sched_ext: Use bitfields for boolean warning flags Tejun Heo
2025-09-23  7:45   ` Andrea Righi
2025-09-23 16:00     ` Tejun Heo
2025-09-23 16:58   ` [PATCH v2 " Tejun Heo
2025-09-23 18:45     ` Andrea Righi
2025-09-22  1:32 ` [PATCH 5/7] sched_ext: Add SCX_EFLAG_INITIALIZED to indicate successful ops.init() Tejun Heo
2025-09-23  8:08   ` Andrea Righi
2025-09-22  1:32 ` [PATCH 6/7] sched_ext: Make qmap dump operation non-destructive Tejun Heo
2025-09-23  8:09   ` Andrea Righi
2025-09-22  1:32 ` [PATCH 7/7] tools/sched_ext: scx_qmap: Make debug output quieter by default Tejun Heo
2025-09-23  8:11   ` Andrea Righi
2025-09-23  7:18 ` [PATCH 1/7] sched_ext: Use rhashtable_lookup() instead of rhashtable_lookup_fast() Andrea Righi
2025-09-23 15:59   ` Tejun Heo
2025-09-23 18:47     ` Andrea Righi
2025-09-23 19:13 ` Tejun Heo
2025-09-24  6:14 ` Andrea Righi
2025-09-24  6:38   ` Tejun Heo
2025-09-24  8:26     ` Andrea Righi
2025-09-24 18:00       ` Tejun Heo
2025-10-22 21:37 ` Andrea Righi
2025-10-22 21:56 ` Tejun Heo

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