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From: Tao Chen <chen.dylane@linux.dev>
To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
	namhyung@kernel.org, mark.rutland@arm.com,
	alexander.shishkin@linux.intel.com, jolsa@kernel.org,
	irogers@google.com, adrian.hunter@intel.com,
	kan.liang@linux.intel.com, fweisbec@gmail.com
Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	Tao Chen <chen.dylane@linux.dev>
Subject: [PATCH linux-next v2] perf/ring_buffer: Add EPOLLRDNORM flag for poll
Date: Fri, 14 Mar 2025 11:00:36 +0800	[thread overview]
Message-ID: <20250314030036.2543180-1-chen.dylane@linux.dev> (raw)

The poll man page says POLLRDNORM is equivalent to POLLIN. For poll,
it seems that if user sets pollfd with POLLRDNORM in userspace, perf_poll
will not return until timeout even if perf_output_wakeup called, whereas POLLIN
returns.

Fixes: 76369139ceb9 ("perf: Split up buffer handling from core code")
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
---
 kernel/events/ring_buffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Change list:
- v1 -> v2:
    - add changelog
- v1
  https://lore.kernel.org/all/20250313051047.2436098-1-chen.dylane@linux.dev

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 59a52b1a1..5130b119d 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -19,7 +19,7 @@
 
 static void perf_output_wakeup(struct perf_output_handle *handle)
 {
-	atomic_set(&handle->rb->poll, EPOLLIN);
+	atomic_set(&handle->rb->poll, EPOLLIN | EPOLLRDNORM);
 
 	handle->event->pending_wakeup = 1;
 
-- 
2.43.0


             reply	other threads:[~2025-03-14  3:01 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-14  3:00 Tao Chen [this message]
2025-03-17  7:47 ` [tip: perf/core] perf/ring_buffer: Allow the EPOLLRDNORM flag for poll tip-bot2 for Tao Chen

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