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From: Usama Arif <usamaarif642@gmail.com>
To: rppt@kernel.org, Andrew Morton <akpm@linux-foundation.org>
Cc: kas@kernel.org, changyuanl@google.com, graf@amazon.com,
	leitao@debian.org, thevlad@meta.com, pratyush@kernel.org,
	dave.hansen@linux.intel.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, kernel-team@meta.com,
	Usama Arif <usamaarif642@gmail.com>
Subject: [PATCH v3 0/2] mm: only mark/clear KHO scratch memory when needed
Date: Fri, 28 Nov 2025 17:29:32 +0000	[thread overview]
Message-ID: <20251128173257.969322-1-usamaarif642@gmail.com> (raw)

The scratch memory for kexec handover is used to bootstrap the
kexec'ed kernel. Only the 1st 1MB is used as scratch, and its a
hack to get around limitations with KHO. It is only needed when
CONFIG_KEXEC_HANDOVER is enabled and only if it is a KHO boot
(both checked by is_kho_boot). Add check to prevent marking a KHO
scratch region unless needed.

CONFIG_MEMBLOCK_KHO_SCRATCH is also removed as its only selected
by KEXEC_HANDOVER.

v2 -> v3:
- is_kho_boot already has stubs when CONFIG_KEXEC_HANDOVER=n,
  no need to move the functions under CONFIG_KEXEC_HANDOVER (Pratyush
  Yadav)
- Commit messsage improvements

v1 -> v2:
- Remove CONFIG_MEMBLOCK_KHO_SCRATCH (Kiryl Shutsemau)
- Move memblock_mark/clear_kho_scratch under alread existing
  CONFIG_KEXEC_HANDOVER in memblock.c.


Usama Arif (2):
  mm/memblock: remove CONFIG_MEMBLOCK_KHO_SCRATCH option
  mm/memblock: only mark/clear KHO scratch memory when needed

 include/linux/memblock.h |  2 +-
 kernel/Kconfig.kexec     |  1 -
 mm/Kconfig               |  4 ----
 mm/memblock.c            | 18 +++++++++++-------
 4 files changed, 12 insertions(+), 13 deletions(-)

-- 
2.47.3



             reply	other threads:[~2025-11-28 17:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-28 17:29 Usama Arif [this message]
2025-11-28 17:29 ` [PATCH v3 1/2] mm/memblock: remove CONFIG_MEMBLOCK_KHO_SCRATCH option Usama Arif
2025-11-28 17:29 ` [PATCH v3 2/2] mm/memblock: only mark/clear KHO scratch memory when needed Usama Arif
2025-11-30  8:52   ` Mike Rapoport
2025-12-04 14:04     ` Pasha Tatashin
2025-12-04 14:51       ` Usama Arif
2025-12-04 17:52         ` Mike Rapoport
2025-12-04 19:27           ` Usama Arif

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