Re: [PATCH -next] riscv: TRANSPARENT_HUGEPAGE: depends on MMU
From: Mike Rapoport <rppt@kernel.org>
Date: 2021-05-25 10:33:37
Also in:
linux-riscv
Subsystem:
memory management, memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
On Mon, May 24, 2021 at 05:13:02PM -0700, Randy Dunlap wrote:
Fix a Kconfig warning and many build errors:
WARNING: unmet direct dependencies detected for COMPACTION
Depends on [n]: MMU [=n]
Selected by [y]:
- TRANSPARENT_HUGEPAGE [=y] && HAVE_ARCH_TRANSPARENT_HUGEPAGE [=y]
and the subseqent thousands of build errors and warnings.
Fixes: e88b333142e4 ("riscv: mm: add THP support on 64-bit")
Signed-off-by: Randy Dunlap <redacted>
Cc: Paul Walmsley <redacted>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nanyong Sun <redacted>Acked-by: Mike Rapoport <redacted>
---
I really think that mm/Kconfig should have "depends on MMU" for
TRANSPARENT_HUGEPAGE, but commit 15626062f4a9 from 2012
("thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE") thought
differently. I.e., mm/Kconfig should be protecting all arches
against this Kconfig problem.We could
diff --git a/mm/Kconfig b/mm/Kconfig
index 02d44e3420f5..85bc8bf32e7b 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig@@ -403,7 +403,7 @@ config NOMMU_INITIAL_TRIM_EXCESS config TRANSPARENT_HUGEPAGE bool "Transparent Hugepage Support" - depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE + depends on MMU && HAVE_ARCH_TRANSPARENT_HUGEPAGE select COMPACTION select XARRAY_MULTI help
but in a sense HAVE_ARCH_TRANSPARENT_HUGEPAGE should imply that MMU is selected :)
quoted hunk ↗ jump to hunk
arch/riscv/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)--- linux-next-20210524.orig/arch/riscv/Kconfig +++ linux-next-20210524/arch/riscv/Kconfig@@ -106,7 +106,7 @@ config RISCV select SYSCTL_EXCEPTION_TRACE select THREAD_INFO_IN_TASK select UACCESS_MEMCPY if !MMU - select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT + select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU config ARCH_MMAP_RND_BITS_MIN default 18 if 64BIT
-- Sincerely yours, Mike.