linux-kernel - [PATCH v1 0/2] Free contiguous order-0 pages efficiently

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Message-ID: <20260105161741.3952456-1-ryan.roberts@arm.com>
Date: Mon,  5 Jan 2026 16:17:36 +0000
From: Ryan Roberts <ryan.roberts@....com>
To: Andrew Morton <akpm@...ux-foundation.org>,
	David Hildenbrand <david@...nel.org>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Mike Rapoport <rppt@...nel.org>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Michal Hocko <mhocko@...e.com>,
	Brendan Jackman <jackmanb@...gle.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Zi Yan <ziy@...dia.com>,
	Uladzislau Rezki <urezki@...il.com>,
	"Vishal Moola (Oracle)" <vishal.moola@...il.com>
Cc: Ryan Roberts <ryan.roberts@....com>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 0/2] Free contiguous order-0 pages efficiently

Hi All,

A recent change to vmalloc caused some performance benchmark regressions (see
[1]). I'm attempting to fix that (and at the same time signficantly improve
beyond the baseline) by freeing a contiguous set of order-0 pages as a batch.

At the same time I observed that free_contig_range() was essentially doing the
same thing as vfree() so I've fixed it there too.

I think I've convinced myself that free_pages_prepare() per order-0 page
followed by a single free_frozen_page_commit() or free_one_page() for the high
order block is safe/correct, but would be good if a page_alloc expert can
confirm!

Applies against today's mm-unstable (344d3580dacd). All mm selftests run and
pass.

Thanks,
Ryan

Ryan Roberts (2):
  mm/page_alloc: Optimize free_contig_range()
  vmalloc: Optimize vfree

 include/linux/gfp.h |   1 +
 mm/page_alloc.c     | 116 +++++++++++++++++++++++++++++++++++++++-----
 mm/vmalloc.c        |  29 +++++++----
 3 files changed, 125 insertions(+), 21 deletions(-)

--
2.43.0