From nobody Sun Oct 5 00:07:07 2025 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 38A9C2EBDD2 for ; Tue, 12 Aug 2025 10:46:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754995576; cv=none; b=RBqpJTXsXOx4o7foDgO9nJtstCWvwMSxgt+J9OhVgFeKYRBL2cLNeK0NyhDy5rm/abbUY9TMlSaHoWfsOSi95ifVqbQBxq+qBLCH0Vp1rb9HjFFsi0dlgCPLwfQ7xGgnwVBzwmrv61qxnPGcFAZYcsf3StYZbfbVWt+z3rnAOpg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754995576; c=relaxed/simple; bh=1tsQSdG3yZOrZGZhMvetPvkheLSWSMiaRFMeyD+344g=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=oQU8BphDvVaocWObRs9YRTegKkvkqR27dUa7IH9FuIYKI+/j8wDWhoOTtTXEYHB3c2wROhCNP2YZ49RIRCuLZ8Byv9UA4HdSj1z5cyDbsTGCXPV/M4IdRWOQHJ4TEZCBW3w6q+bs/IH846v4Ila9kzFUJXvqF3lrrKKtOVYWT1g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ioGtXGnO; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ioGtXGnO" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=p++m+D3TzbqZgFFa4l1hUbPQS1hbYRMWFqRcL82KSek=; b=ioGtXGnORxciG9LHA+ZahVlm93 lsapz6RaQ/xuHK73D0pU54NwGdMvHALWFKWujYviuZ8UslqtR+zePiAgPuKQBCRo2ZKWt5na6M+I6 FrOg0xSFcbViSJhqbCDzqBTJvCQO6mw1hmFX4lHC6At8oK/tc2TsjZ3guniw2vrHZvpspZDdP2TNG Lqvs475kGLNvbgMLFdJjtLQUYdAyUllN+x7WhEjX+iu8BOc+Io17+jYP27Gz2bOrfltBwXGVryCRj V4LMYTtKRW2BdNMVvb26QOG4+iQ+z1Au3QtOOWhAzRRqaj58lrthp1ytbrlJ/n/ktSpAGcxajkPak yjF70r9w==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1ulmWB-0000000FmkC-25jQ; Tue, 12 Aug 2025 10:46:11 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 0) id C4E85302EC2; Tue, 12 Aug 2025 12:46:09 +0200 (CEST) Message-ID: <20250812104019.956479989@infradead.org> User-Agent: quilt/0.68 Date: Tue, 12 Aug 2025 12:39:12 +0200 From: Peter Zijlstra To: tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, torvalds@linuxfoundation.org, mingo@kernel.org, namhyung@kernel.org, acme@redhat.com, kees@kernel.org Subject: [PATCH v3 14/15] perf: Identify the 0->1 transition for event::mmap_count References: <20250812103858.234850285@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Needed because refcount_inc() doesn't allow the 0->1 transition. Suggested-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Lorenzo Stoakes --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7033,7 +7033,7 @@ static int perf_mmap_rb(struct vm_area_s perf_event_update_userpage(event); =20 perf_mmap_account(vma, user_extra, extra); - atomic_inc(&event->mmap_count); + atomic_set(&event->mmap_count, 1); =20 return 0; }