From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51A6B35E55D; Tue, 26 May 2026 15:22:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779808939; cv=none; b=W8GQv0AuFmSKs9I62MsKB1Rjtg69xPp6dhuGfkxvlY8oubrT0bJkun19UdlOt9B+yaNBPJTF8lR9kHHe7aT2FN7wSZQ0NL7VzRGUOGSQ2VH6kKjyOpvYahmwVk3G0M1a5AS6aNu3Fuglniv35x/6FJM00DOjHTPRYt7fEr5otNM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779808939; c=relaxed/simple; bh=ZkuDvku83t97+XBYhvWo9Uns8mWKuzVanjRuYZy6FiQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cnA2rI+n8uWGtpGRCZJ86bGwV+b/DP8M7mqQzg7Q2ZpNbSCJHT7nivtuBH40FZXXomLoqUxWRC7wC4/JKl1lwJEt+boqNNBJKxm5xO/Jbsq3m6PtWuyfIDHZyMDpK0s3GhNZCxxGrNGFwbNPaGLAwiBkuPJlZyz4TItmTByIEVc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Kg/XUJJC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Kg/XUJJC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B364E1F00A3F; Tue, 26 May 2026 15:22:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779808938; bh=uDm3SE+wj14K2ZLchywSqxzxQe3Kn/14VxTpFaIuLFY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Kg/XUJJC6RliATTRDG0SVtVXqL+gpknSIcmVOIoKNykD6tNqjBAEFeaE7bQRoUg5A 9EdvJ9xYw4dInTc8CofmzQ8GnTo87jmZS8kEdpTaTJYFevP0X7MLEXCCjo0mGj0mT7 rPvjp+13uK+UU1Mm5OMSFcbh9tWK8rDBm7KERjYtQQjvZtfCmTjLRCebIV5EogIPQg c3gKSlvVdCpe3s2vu16yD83meu50VgSFQQr1lpoeFYUpNHNBViKWdPeONvd+pf9ZnK 1mZIO8lAO2+6kKzBapZUUV6oG2DSjvGEP2jdFRT0ENGHv3HDMcxno+wRRuXZMnoFcg wOYbyp7FLadxw== Received: from phl-compute-01.internal (phl-compute-01.internal [10.202.2.41]) by mailfauth.phl.internal (Postfix) with ESMTP id 0BE25F40076; Tue, 26 May 2026 11:22:16 -0400 (EDT) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-01.internal (MEProxy); Tue, 26 May 2026 11:22:16 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTFpmA1McbnqjIdDoCcC8/dKh9RDeYcaA/XB6dgQZoHsdisS7Rnte/RUY2pDCqsaCf lYH/GXfkGRmzTYnB4S+g0DoIzy4KUSXH1v1hqWsXA4v5WIAvvT6c8zNgUsod23Kpq2+47O yYMzbMVdimQJPpKCDvwUMQiSwLgkBGzQ1ckebHI5CwcU5PXtm0paPap1/zDmdG+vWcQc/M pmWI2idDed0xMRSQV9XOsN/PBFcH6SBYELvyO/AtrMtpHg8r71AQlMzDlEp1H1iVazK3oS DonyrliF9qRbQD87XBn6QOt2bC/09pqeijaNsBJFU0GwQ/sar+bEYdVoRVtkXuEiBwHIRY NvmRzh3HKhTixLa9Yn44SeOJDKNB4emdE7Zg6eb6qu0SJAJyYk7TBJPpbtw/8VWjWgRilP LwsQlLqbO47h14uao9G3vhgfKyEJrZKGPAdXvTlqYclnCbpAmE2nXMAcxfN0wHm76Lme6N Iowx0J9CdnEy+E189qIJZ5I9dE4gMQBaqH1/S62Ot9HGBFylDe3CpM4uEAUHkRI0uUEOi1 wh+Jq9LdZKZrCAHLtoZKbuj1vubHqyERkwPxdgYDLYAlHqxQsggXqKiHFgg1xD6KC9fGFr utR9wT6WMzr3FFToF4LzVvv9rilxQmyrMtcdfdcqAwv3Hg6NWmB4R0Co56bQ X-ME-Proxy: Feedback-ID: i8dbe485b:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 26 May 2026 11:22:15 -0400 (EDT) From: Boqun Feng To: Peter Zijlstra Cc: Catalin Marinas , Will Deacon , Jonas Bonn , Stefan Kristiansson , Stafford Horne , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Boqun Feng , Waiman Long , Andrew Morton , Andrii Nakryiko , Eduard Zingerman , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , Shuah Khan , Miguel Ojeda , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jinjie Ruan , Lyude Paul , Thomas Huth , Sohil Mehta , "Xin Li (Intel)" , Pawan Gupta , Nikunj A Dadhania , Joel Fernandes , Andy Shevchenko , Randy Dunlap , Yury Norov , Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-s390@vger.kernel.org, linux-arch@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, rust-for-linux@vger.kernel.org, =?UTF-8?q?Onur=20=C3=96zkan?= , Daniel Almeida Subject: [PATCH v2 09/12] sched: Avoid signed comparison of preempt_count() in __cant_migrate() Date: Tue, 26 May 2026 08:21:45 -0700 Message-ID: <20260526152148.30514-10-boqun@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260526152148.30514-1-boqun@kernel.org> References: <20260526152148.30514-1-boqun@kernel.org> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Currently preempt_count() is always a non-negative int on all archs (PREEMPT_NEED_RESCHED archs will mask out the MSB when return preempt_count()), hence the checking in __cant_migrate() is in fact just checking whether preempt_count() is 0 or not. In a future change, we are going to use all the 32 bits of preempt_count(), which would make negative int values possible from preempt_count(). Therefore convert the "> 0" comparison into a zero checking to prepare for the future change. No functional changes are intended. Signed-off-by: Boqun Feng --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 75dba7cc09bd..636e6a15f104 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9207,7 +9207,7 @@ void __cant_migrate(const char *file, int line) if (!IS_ENABLED(CONFIG_PREEMPT_COUNT)) return; - if (preempt_count() > 0) + if (preempt_count()) return; if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) -- 2.50.1 (Apple Git-155)