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Message-ID: <20240620175703.605111-11-yury.norov@gmail.com>
Date: Thu, 20 Jun 2024 10:56:33 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
Fenghua Yu <fenghua.yu@...el.com>,
Dave Jiang <dave.jiang@...el.com>,
Vinod Koul <vkoul@...nel.org>,
dmaengine@...r.kernel.org
Cc: Yury Norov <yury.norov@...il.com>,
Alexey Klimov <alexey.klimov@...aro.org>,
Bart Van Assche <bvanassche@....org>,
Jan Kara <jack@...e.cz>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Matthew Wilcox <willy@...radead.org>,
Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Sergey Shtylyov <s.shtylyov@....ru>
Subject: [PATCH v4 10/40] dmaengine: idxd: optimize perfmon_assign_event()
The function searches used_mask for a set bit in a for-loop bit by
bit. Simplify it by using atomic find_and_set_bit(), and make a nice
one-liner.
Signed-off-by: Yury Norov <yury.norov@...il.com>
Reviewed-by: Dave Jiang <dave.jiang@...el.com>
Acked-by: Vinod Koul <vkoul@...nel.org>
Reviewed-by: Fenghua Yu <fenghua.yu@...el.com>
---
drivers/dma/idxd/perfmon.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/dma/idxd/perfmon.c b/drivers/dma/idxd/perfmon.c
index 5e94247e1ea7..063ee78fb132 100644
--- a/drivers/dma/idxd/perfmon.c
+++ b/drivers/dma/idxd/perfmon.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2020 Intel Corporation. All rights rsvd. */
+#include <linux/find_atomic.h>
#include <linux/sched/task.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include "idxd.h"
@@ -134,13 +135,9 @@ static void perfmon_assign_hw_event(struct idxd_pmu *idxd_pmu,
static int perfmon_assign_event(struct idxd_pmu *idxd_pmu,
struct perf_event *event)
{
- int i;
-
- for (i = 0; i < IDXD_PMU_EVENT_MAX; i++)
- if (!test_and_set_bit(i, idxd_pmu->used_mask))
- return i;
+ int i = find_and_set_bit(idxd_pmu->used_mask, IDXD_PMU_EVENT_MAX);
- return -EINVAL;
+ return i < IDXD_PMU_EVENT_MAX ? i : -EINVAL;
}
/*
--
2.43.0
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