From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.ilvokhin.com (mail.ilvokhin.com [178.62.254.231]) (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 9A2DD3822B7; Tue, 3 Mar 2026 14:26:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.62.254.231 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772547964; cv=none; b=WWjfgCJ7jjvbkaAibZCjbbd+H5vneIPugib43HLeaWyD4q9UmBdDp98pFQrX38lh+hFa7DN2AMPBHlzJyV46SNg14vwbjtmvx9iPkUwHCuiGqGhJEMfkFJancncMrFvZcOQX9teA2QdLfycYFQy9l3JGv6C/u/rXqxxLycbMXTw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772547964; c=relaxed/simple; bh=qnDLvfOYAMIQg8avmH5Pha1NK4JIjQHZjXzlt3EZXyk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VgaGrHkQQDpt/CN8zvNRSxYaTJD20IFk4+eJh7H4vX/fYFIlAwLi29wqUD3DVld14I7yh0HhRPP/YrYvOblkKS18q9+lx9Tj+lXhcGghMYWfRzjK3wnPJ0Epig8YIIRCAAuwN9Cn1mMxx21KHHUbVHTR+GTLYw8Ig1cDpBHtFYY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=ilvokhin.com; spf=pass smtp.mailfrom=ilvokhin.com; dkim=pass (1024-bit key) header.d=ilvokhin.com header.i=@ilvokhin.com header.b=cR1o2MTN; arc=none smtp.client-ip=178.62.254.231 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=ilvokhin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ilvokhin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ilvokhin.com header.i=@ilvokhin.com header.b="cR1o2MTN" Received: from shell.ilvokhin.com (shell.ilvokhin.com [138.68.190.75]) (Authenticated sender: d@ilvokhin.com) by mail.ilvokhin.com (Postfix) with ESMTPSA id DDD3FB3100; Tue, 03 Mar 2026 14:25:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ilvokhin.com; s=mail; t=1772547960; bh=LNVFddGP/SQV1eCKP4+0NtVgj/0UkiifX6TCYuJFdss=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=cR1o2MTNmIgJM6CSLHyWv2tw4JfyPhDpRjgo6tiqz7f4s2IZ5YCSw5z6tNQXgor7/ fhP27pb7RcpWqjF+WmGNTd/A4By/OK271NUgciUW8p2iipyod2Rkd4JS3l1K9JMASN /hTSH+NuohXjtj/oRcJWrcMcZsLRnqGsDfXUKBlg= Date: Tue, 3 Mar 2026 14:25:55 +0000 From: Dmitry Ilvokhin To: Andrew Morton Cc: "Vlastimil Babka (SUSE)" , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Axel Rasmussen , Yuanchu Xie , Wei Xu , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , "Rafael J. Wysocki" , Pavel Machek , Len Brown , Brendan Jackman , Johannes Weiner , Zi Yan , Oscar Salvador , Qi Zheng , Shakeel Butt , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-pm@vger.kernel.org, SeongJae Park Subject: Re: [PATCH v4 4/5] mm: rename zone->lock to zone->_lock Message-ID: References: <0f340324-502b-4719-b3e7-c7ccd4378385@kernel.org> <20260302143743.220eed4feb36d7572fe726cc@linux-foundation.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260302143743.220eed4feb36d7572fe726cc@linux-foundation.org> On Mon, Mar 02, 2026 at 02:37:43PM -0800, Andrew Morton wrote: > On Mon, 2 Mar 2026 15:10:03 +0100 "Vlastimil Babka (SUSE)" wrote: > > > On 2/27/26 17:00, Dmitry Ilvokhin wrote: > > > This intentionally breaks direct users of zone->lock at compile time so > > > all call sites are converted to the zone lock wrappers. Without the > > > rename, present and future out-of-tree code could continue using > > > spin_lock(&zone->lock) and bypass the wrappers and tracing > > > infrastructure. > > > > > > No functional change intended. > > > > > > Suggested-by: Andrew Morton > > > Signed-off-by: Dmitry Ilvokhin > > > Acked-by: Shakeel Butt > > > Acked-by: SeongJae Park > > > > I see some more instances of 'zone->lock' in comments in > > include/linux/mmzone.h and under Documentation/ but otherwise LGTM. > > > > I fixed (most of) that in the previous version but my fix was lost. Thanks for the fixups, Andrew. I still see a few 'zone->lock' references in Documentation remain on mm-new. This patch cleans them up, as noted by Vlastimil. I'm happy to adjust this patch if anything else needs attention. >From 9142d5a8b60038fa424a6033253960682e5a51f4 Mon Sep 17 00:00:00 2001 From: Dmitry Ilvokhin Date: Tue, 3 Mar 2026 06:13:13 -0800 Subject: [PATCH] mm: fix remaining zone->lock references Signed-off-by: Dmitry Ilvokhin --- Documentation/mm/physical_memory.rst | 4 ++-- Documentation/trace/events-kmem.rst | 8 ++++---- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/Documentation/mm/physical_memory.rst b/Documentation/mm/physical_memory.rst index b76183545e5b..e344f93515b6 100644 --- a/Documentation/mm/physical_memory.rst +++ b/Documentation/mm/physical_memory.rst @@ -500,11 +500,11 @@ General ``nr_isolate_pageblock`` Number of isolated pageblocks. It is used to solve incorrect freepage counting problem due to racy retrieving migratetype of pageblock. Protected by - ``zone->lock``. Defined only when ``CONFIG_MEMORY_ISOLATION`` is enabled. + ``zone_lock``. Defined only when ``CONFIG_MEMORY_ISOLATION`` is enabled. ``span_seqlock`` The seqlock to protect ``zone_start_pfn`` and ``spanned_pages``. It is a - seqlock because it has to be read outside of ``zone->lock``, and it is done in + seqlock because it has to be read outside of ``zone_lock``, and it is done in the main allocator path. However, the seqlock is written quite infrequently. Defined only when ``CONFIG_MEMORY_HOTPLUG`` is enabled. diff --git a/Documentation/trace/events-kmem.rst b/Documentation/trace/events-kmem.rst index 68fa75247488..3c20a972de27 100644 --- a/Documentation/trace/events-kmem.rst +++ b/Documentation/trace/events-kmem.rst @@ -57,7 +57,7 @@ the per-CPU allocator (high performance) or the buddy allocator. If pages are allocated directly from the buddy allocator, the mm_page_alloc_zone_locked event is triggered. This event is important as high -amounts of activity imply high activity on the zone->lock. Taking this lock +amounts of activity imply high activity on the zone_lock. Taking this lock impairs performance by disabling interrupts, dirtying cache lines between CPUs and serialising many CPUs. @@ -79,11 +79,11 @@ contention on the lruvec->lru_lock. mm_page_pcpu_drain page=%p pfn=%lu order=%d cpu=%d migratetype=%d In front of the page allocator is a per-cpu page allocator. It exists only -for order-0 pages, reduces contention on the zone->lock and reduces the +for order-0 pages, reduces contention on the zone_lock and reduces the amount of writing on struct page. When a per-CPU list is empty or pages of the wrong type are allocated, -the zone->lock will be taken once and the per-CPU list refilled. The event +the zone_lock will be taken once and the per-CPU list refilled. The event triggered is mm_page_alloc_zone_locked for each page allocated with the event indicating whether it is for a percpu_refill or not. @@ -92,7 +92,7 @@ which triggers a mm_page_pcpu_drain event. The individual nature of the events is so that pages can be tracked between allocation and freeing. A number of drain or refill pages that occur -consecutively imply the zone->lock being taken once. Large amounts of per-CPU +consecutively imply the zone_lock being taken once. Large amounts of per-CPU refills and drains could imply an imbalance between CPUs where too much work is being concentrated in one place. It could also indicate that the per-CPU lists should be a larger size. Finally, large amounts of refills on one CPU -- 2.47.3