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From: Liao Chang <liaochang1@huawei.com>
To: <mhiramat@kernel.org>, <oleg@redhat.com>, <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>,
	<andrii.nakryiko@gmail.com>
Cc: <linux-kernel@vger.kernel.org>,
	<linux-trace-kernel@vger.kernel.org>,
	<linux-perf-users@vger.kernel.org>, <bpf@vger.kernel.org>
Subject: [PATCH v5 1/2] uprobes: Remove redundant spinlock in uprobe_deny_signal()
Date: Fri, 24 Jan 2025 09:38:25 +0000	[thread overview]
Message-ID: <20250124093826.2123675-2-liaochang1@huawei.com> (raw)
In-Reply-To: <20250124093826.2123675-1-liaochang1@huawei.com>

Since clearing a bit in thread_info is an atomic operation, the spinlock
is redundant and can be removed, reducing lock contention is good for
performance.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Liao Chang <liaochang1@huawei.com>
---
 kernel/events/uprobes.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index e421a5f2ec7d..7a3348dfedeb 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -2298,9 +2298,7 @@ bool uprobe_deny_signal(void)
 	WARN_ON_ONCE(utask->state != UTASK_SSTEP);
 
 	if (task_sigpending(t)) {
-		spin_lock_irq(&t->sighand->siglock);
 		clear_tsk_thread_flag(t, TIF_SIGPENDING);
-		spin_unlock_irq(&t->sighand->siglock);
 
 		if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) {
 			utask->state = UTASK_SSTEP_TRAPPED;
-- 
2.34.1


  reply	other threads:[~2025-01-24  9:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-24  9:38 [PATCH v5 0/2] uprobes: Improve scalability by reducing the contention on siglock Liao Chang
2025-01-24  9:38 ` Liao Chang [this message]
2025-01-24 15:27   ` [PATCH v5 1/2] uprobes: Remove redundant spinlock in uprobe_deny_signal() Steven Rostedt
2025-01-24 17:25     ` Oleg Nesterov
2025-01-24 17:38       ` Oleg Nesterov
2025-01-24  9:38 ` [PATCH v5 2/2] uprobes: Remove the spinlock within handle_singlestep() Liao Chang
2025-01-27 11:28 ` [PATCH v5 0/2] uprobes: Improve scalability by reducing the contention on siglock Peter Zijlstra

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