From: Steven Rostedt <rostedt@goodmis.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Ilvokhin <d@ilvokhin.com>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Brendan Jackman <jackmanb@google.com>,
Johannes Weiner <hannes@cmpxchg.org>, Zi Yan <ziy@nvidia.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com, Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 1/8] mm: use zone lock guard in reserve_highatomic_pageblock()
Date: Fri, 6 Mar 2026 13:00:52 -0500 [thread overview]
Message-ID: <20260306130052.7da8eab3@gandalf.local.home> (raw)
In-Reply-To: <20260306095336.a79fcc869a7f6d2b2e97501b@linux-foundation.org>
[ Adding Peter ]
On Fri, 6 Mar 2026 09:53:36 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:
> On Fri, 6 Mar 2026 16:05:35 +0000 Dmitry Ilvokhin <d@ilvokhin.com> wrote:
>
> > Use the newly introduced zone_lock_irqsave lock guard in
> > reserve_highatomic_pageblock() to replace the explicit lock/unlock and
> > goto out_unlock pattern with automatic scope-based cleanup.
> >
> > ...
> >
> > - zone_lock_irqsave(zone, flags);
> > + guard(zone_lock_irqsave)(zone);
>
> guard() is cute, but this patch adds a little overhead - defconfig
> page_alloc.o text increases by 32 bytes, presumably all in
> reserve_highatomic_pageblock(). More instructions, larger cache
> footprint.
>
> So we're adding a little overhead to every user's Linux machine for all
> time. In return for which the developers get a little convenience and
> maintainability.
I think maintainability is of importance. Is there any measurable slowdown?
Or are we only worried about the text size increase?
>
> Is it worth it?
This is being done all over the kernel. Perhaps we should look at ways to
make the generic infrastructure more performant?
-- Steve
next prev parent reply other threads:[~2026-03-06 18:01 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-06 16:05 [PATCH 0/8] mm: introduce zone lock guards Dmitry Ilvokhin
2026-03-06 16:05 ` [PATCH 1/8] mm: use zone lock guard in reserve_highatomic_pageblock() Dmitry Ilvokhin
2026-03-06 17:53 ` Andrew Morton
2026-03-06 18:00 ` Steven Rostedt [this message]
2026-03-06 18:24 ` Vlastimil Babka
2026-03-06 18:33 ` Andrew Morton
2026-03-06 18:46 ` Steven Rostedt
2026-03-06 16:05 ` [PATCH 2/8] mm: use zone lock guard in unset_migratetype_isolate() Dmitry Ilvokhin
2026-03-06 16:05 ` [PATCH 3/8] mm: use zone lock guard in unreserve_highatomic_pageblock() Dmitry Ilvokhin
2026-03-06 16:10 ` Steven Rostedt
2026-03-06 16:05 ` [PATCH 4/8] mm: use zone lock guard in set_migratetype_isolate() Dmitry Ilvokhin
2026-03-06 16:05 ` [PATCH 5/8] mm: use zone lock guard in take_page_off_buddy() Dmitry Ilvokhin
2026-03-06 16:05 ` [PATCH 6/8] mm: use zone lock guard in put_page_back_buddy() Dmitry Ilvokhin
2026-03-06 16:05 ` [PATCH 7/8] mm: use zone lock guard in free_pcppages_bulk() Dmitry Ilvokhin
2026-03-06 16:05 ` [PATCH 8/8] mm: use zone lock guard in __offline_isolated_pages() Dmitry Ilvokhin
2026-03-06 16:15 ` [PATCH 0/8] mm: introduce zone lock guards Steven Rostedt
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