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

[Ryan Roberts <ryan.roberts@arm.com>]

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(-)

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2.43.0