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From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
To: linux-mm@kvack.org
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <chleroy@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Chris Li <chrisl@kernel.org>, Kairui Song <kasong@tencent.com>,
	Kemeng Shi <shikemeng@huaweicloud.com>,
	Nhat Pham <nphamcs@gmail.com>, Baoquan He <baoquan.he@linux.dev>,
	Barry Song <baohua@kernel.org>,
	Youngjun Park <youngjun.park@lge.com>,
	David Hildenbrand <david@kernel.org>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	Sayali Patil <sayalip@linux.ibm.com>,
	"Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Subject: [RFC 0/4] mm, swap: Enable THP SWAP for PowerPC Book3S64
Date: Tue,  9 Jun 2026 18:49:30 +0530	[thread overview]
Message-ID: <cover.1781000840.git.ritesh.list@gmail.com> (raw)

On PowerPC Book3S64, MMU is selected at runtime, so macros like PMD_SHIFT are
effectively runtime variables in the Book3S64 code. THP swap code uses these
macros for e.g. to size some of its array data structures based on PMD_ORDER.
This patch series makes that usage dependent on the runtime variable.

Sayali did some performance runs of this on Book3S64 with Radix and it gives
40-50% performance improvement. We also plan to run it with Hash, will soon
update the results.

Note that this patch series is based out of linux-next (next-20260608).

Ritesh Harjani (IBM) (4):
  include/linux/swap.h: Remove unused leftovers
  mm, swap: make SWAPFILE_CLUSTER runtime
  mm, swap: make SWAP_NR_ORDERS runtime
  powerpc: Kconfig: Enable THP_SWAP on Book3S64

 arch/powerpc/platforms/Kconfig.cputype |   1 +
 include/linux/swap.h                   |  17 +---
 mm/swap.h                              |   5 +-
 mm/swap_table.h                        |   6 +-
 mm/swapfile.c                          | 132 ++++++++++++++++++-------
 5 files changed, 106 insertions(+), 55 deletions(-)

--
2.39.5


             reply	other threads:[~2026-06-09 13:19 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-09 13:19 Ritesh Harjani (IBM) [this message]
2026-06-09 13:19 ` [RFC 1/4] include/linux/swap.h: Remove unused leftovers Ritesh Harjani (IBM)
2026-06-09 13:19 ` [RFC 2/4] mm, swap: make SWAPFILE_CLUSTER runtime Ritesh Harjani (IBM)
2026-06-09 13:19 ` [RFC 3/4] mm, swap: make SWAP_NR_ORDERS runtime Ritesh Harjani (IBM)
2026-06-09 13:19 ` [RFC 4/4] powerpc: Kconfig: Enable THP_SWAP on Book3S64 Ritesh Harjani (IBM)
2026-06-09 15:54 ` [RFC 0/4] mm, swap: Enable THP SWAP for PowerPC Book3S64 YoungJun Park

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