From: Leo Yan <leo.yan@arm.com>
To: Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@arm.com>,
James Clark <james.clark@linaro.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Tamas Petz <tamas.petz@arm.com>,
Tamas Zsoldos <tamas.zsoldos@arm.com>,
Suyash Mahar <smahar@meta.com>, Amir Ayupov <aaupov@fb.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, coresight@lists.linaro.org,
Leo Yan <leo.yan@arm.com>
Subject: [PATCH v2 01/11] coresight: trbe: Remove misleading comment
Date: Fri, 16 Oct 2026 22:11:39 +0100 [thread overview]
Message-ID: <20261016-trbe_buffer_refactor_v2-v2-1-383ac26382fa@arm.com> (raw)
In-Reply-To: <20261016-trbe_buffer_refactor_v2-v2-0-383ac26382fa@arm.com>
Since the rounded-up wakeup address is always higher than the head, the
limit cannot be less than the head caused by wakeup capping.
The described scenario is never valid caused by wakeup capping, remove
the comment to avoid confusion.
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-trbe.c | 16 ++--------------
1 file changed, 2 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 29a1882b1f3c2eb7166f71eeef37badece67039c..ada4794c51f3eb9142cd62f4209affe308142d1b 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -505,10 +505,10 @@ static unsigned long __trbe_normal_offset(struct perf_output_handle *handle)
limit = min(limit, round_up(wakeup, PAGE_SIZE));
/*
- * There are two situation when this can happen i.e limit is before
+ * There is a situation when this can happen i.e limit is before
* the head and hence TRBE cannot be configured.
*
- * 1) head < tail (aligned down with PAGE_SIZE) and also they are both
+ * head < tail (aligned down with PAGE_SIZE) and also they are both
* within the same PAGE size range.
*
* PAGE_SIZE
@@ -519,18 +519,6 @@ static unsigned long __trbe_normal_offset(struct perf_output_handle *handle)
* |$$$$$$$$$$$$$$$$$$$|========|$$$$$$$|
* +------------|------|--------|-------+
* trbe_base trbe_base + nr_pages
- *
- * 2) head < wakeup (aligned up with PAGE_SIZE) < tail and also both
- * head and wakeup are within same PAGE size range.
- *
- * PAGE_SIZE
- * |----------------------|
- *
- * limit head wakeup tail
- * +----|------|-------|--------|-------+
- * |$$$$$$$$$$$|=======|========|$$$$$$$|
- * +----|------|-------|--------|-------+
- * trbe_base trbe_base + nr_pages
*/
if (limit > head)
return limit;
--
2.34.1
next prev parent reply other threads:[~2026-10-16 21:11 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-16 21:11 [PATCH v2 00/11] coresight: trbe: Refactor buffer handling and add trigger support Leo Yan
2026-10-16 21:11 ` Leo Yan [this message]
2026-10-16 21:11 ` [PATCH v2 02/11] coresight: trbe: Refactor next buffer computation Leo Yan
2026-10-16 21:11 ` [PATCH v2 03/11] coresight: trbe: Track trigger count support per CPU Leo Yan
2026-10-16 21:11 ` [PATCH v2 04/11] coresight: trbe: Use trigger mode for buffer maintenance Leo Yan
2026-10-16 21:11 ` [PATCH v2 05/11] coresight: trbe: Leave headroom for stop-on-trigger mode Leo Yan
2026-10-16 21:11 ` [PATCH v2 06/11] coresight: trbe: Save and restore trigger counter Leo Yan
2026-10-16 21:11 ` [PATCH v2 07/11] coresight: trbe: Add KUnit tests for compute normal buffer Leo Yan
2026-10-16 21:11 ` [PATCH v2 08/11] perf cs-etm: Reset decoder on COLLISION flag Leo Yan
2026-10-16 21:11 ` [PATCH v2 09/11] perf cs-etm: Reset per-thread decoder on CPU migration Leo Yan
2026-10-16 21:11 ` [PATCH v2 10/11] perf cs-etm: Reset decoder on AUX offset discontinuity Leo Yan
2026-10-16 21:11 ` [PATCH v2 11/11] perf cs-etm: Set watermark for AUX trace Leo Yan
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