linux-kernel - [PATCH] perf/x86: Add cond_resched() when allocate/release DS buffers

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Message-ID: <20251027212724.1759322-1-namhyung@kernel.org>
Date: Mon, 27 Oct 2025 14:27:24 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH] perf/x86: Add cond_resched() when allocate/release DS buffers

On large systems, it's possible to trigger sched latency warning during
the DS buffer allocation or release.  Add cond_resched() to avoid it.

Reported-by: Eric Dumazet <edumazet@...gle.com>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
 arch/x86/events/intel/ds.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index c0b7ac1c7594ea92..c8e90c5a8d3390ab 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -754,6 +754,7 @@ void release_ds_buffers(void)
 		if (x86_pmu.ds_pebs)
 			release_pebs_buffer(cpu);
 		release_bts_buffer(cpu);
+		cond_resched();
 	}
 }
 
@@ -791,6 +792,8 @@ void reserve_ds_buffers(void)
 
 		if (bts_err && pebs_err)
 			break;
+
+		cond_resched();
 	}
 
 	if (bts_err) {
-- 
2.51.1.838.g19442a804e-goog