From 23baf831a32c04f9a968812511540b1b3e648bf5 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 15 Mar 2023 14:31:33 +0300 Subject: mm, treewide: redefine MAX_ORDER sanely MAX_ORDER currently defined as number of orders page allocator supports: user can ask buddy allocator for page order between 0 and MAX_ORDER-1. This definition is counter-intuitive and lead to number of bugs all over the kernel. Change the definition of MAX_ORDER to be inclusive: the range of orders user can ask from buddy allocator is 0..MAX_ORDER now. [kirill@shutemov.name: fix min() warning] Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box [akpm@linux-foundation.org: fix another min_t warning] [kirill@shutemov.name: fixups per Zi Yan] Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name [akpm@linux-foundation.org: fix underlining in docs] Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/ Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Reviewed-by: Michael Ellerman [powerpc] Cc: "Kirill A. Shutemov" Cc: Zi Yan Signed-off-by: Andrew Morton --- arch/sh/configs/ecovec24_defconfig | 2 +- arch/sh/mm/Kconfig | 17 +++++++---------- 2 files changed, 8 insertions(+), 11 deletions(-) (limited to 'arch/sh') diff --git a/arch/sh/configs/ecovec24_defconfig b/arch/sh/configs/ecovec24_defconfig index b52e14ccb450..4d655e8d4d74 100644 --- a/arch/sh/configs/ecovec24_defconfig +++ b/arch/sh/configs/ecovec24_defconfig @@ -8,7 +8,7 @@ CONFIG_MODULES=y CONFIG_MODULE_UNLOAD=y # CONFIG_BLK_DEV_BSG is not set CONFIG_CPU_SUBTYPE_SH7724=y -CONFIG_ARCH_FORCE_MAX_ORDER=12 +CONFIG_ARCH_FORCE_MAX_ORDER=11 CONFIG_MEMORY_SIZE=0x10000000 CONFIG_FLATMEM_MANUAL=y CONFIG_SH_ECOVEC=y diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig index 411fdc0901f7..40271090bd7d 100644 --- a/arch/sh/mm/Kconfig +++ b/arch/sh/mm/Kconfig @@ -20,13 +20,13 @@ config PAGE_OFFSET config ARCH_FORCE_MAX_ORDER int "Maximum zone order" - range 9 64 if PAGE_SIZE_16KB - default "9" if PAGE_SIZE_16KB - range 7 64 if PAGE_SIZE_64KB - default "7" if PAGE_SIZE_64KB - range 11 64 - default "14" if !MMU - default "11" + range 8 63 if PAGE_SIZE_16KB + default "8" if PAGE_SIZE_16KB + range 6 63 if PAGE_SIZE_64KB + default "6" if PAGE_SIZE_64KB + range 10 63 + default "13" if !MMU + default "10" help The kernel memory allocator divides physically contiguous memory blocks into "zones", where each zone is a power of two number of @@ -35,9 +35,6 @@ config ARCH_FORCE_MAX_ORDER blocks of physically contiguous memory, then you may need to increase this value. - This config option is actually maximum order plus one. For example, - a value of 11 means that the largest free memory block is 2^10 pages. - The page size is not necessarily 4KB. Keep this in mind when choosing a value for this option. -- cgit v1.2.3 From b2a37fb2b54fd46bfa799268717f558d9e168376 Mon Sep 17 00:00:00 2001 From: "Mike Rapoport (IBM)" Date: Fri, 24 Mar 2023 08:22:30 +0300 Subject: sh: reword ARCH_FORCE_MAX_ORDER prompt and help text The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to describe this configuration option. Update both to actually describe what this option does. [rppt@kernel.org: tweak ARCH_FORCE_MAX_ORDER's `range'] Link: https://lkml.kernel.org/r/20230325060828.2662773-12-rppt@kernel.org Link: https://lkml.kernel.org/r/20230324052233.2654090-12-rppt@kernel.org Signed-off-by: Mike Rapoport (IBM) Acked-by: Kirill A. Shutemov Reviewed-by: Zi Yan Cc: Arnd Bergmann Cc: Catalin Marinas Cc: Christophe Leroy Cc: David Miller Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Guo Ren Cc: John Paul Adrian Glaubitz Cc: Max Filippov Cc: Michael Ellerman Cc: Rich Felker Cc: "Russell King (Oracle)" Cc: Will Deacon Cc: Yoshinori Sato Signed-off-by: Andrew Morton --- arch/sh/mm/Kconfig | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'arch/sh') diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig index 40271090bd7d..238b2772751e 100644 --- a/arch/sh/mm/Kconfig +++ b/arch/sh/mm/Kconfig @@ -19,7 +19,7 @@ config PAGE_OFFSET default "0x00000000" config ARCH_FORCE_MAX_ORDER - int "Maximum zone order" + int "Order of maximal physically contiguous allocations" range 8 63 if PAGE_SIZE_16KB default "8" if PAGE_SIZE_16KB range 6 63 if PAGE_SIZE_64KB @@ -28,16 +28,18 @@ config ARCH_FORCE_MAX_ORDER default "13" if !MMU default "10" help - The kernel memory allocator divides physically contiguous memory - blocks into "zones", where each zone is a power of two number of - pages. This option selects the largest power of two that the kernel - keeps in the memory allocator. If you need to allocate very large - blocks of physically contiguous memory, then you may need to - increase this value. + The kernel page allocator limits the size of maximal physically + contiguous allocations. The limit is called MAX_ORDER and it + defines the maximal power of two of number of pages that can be + allocated as a single contiguous block. This option allows + overriding the default setting when ability to allocate very + large blocks of physically contiguous memory is required. The page size is not necessarily 4KB. Keep this in mind when choosing a value for this option. + Don't change if unsure. + config MEMORY_START hex "Physical memory start address" default "0x08000000" -- cgit v1.2.3 From 0495408240c97429cb2d21c6aca717baacb9199f Mon Sep 17 00:00:00 2001 From: "Mike Rapoport (IBM)" Date: Fri, 24 Mar 2023 08:22:31 +0300 Subject: sh: drop ranges for definition of ARCH_FORCE_MAX_ORDER sh defines insane ranges for ARCH_FORCE_MAX_ORDER allowing MAX_ORDER up to 63, which implies maximal contiguous allocation size of 2^63 pages. Drop bogus definitions of ranges for ARCH_FORCE_MAX_ORDER and leave it a simple integer with sensible defaults. Users that *really* need to change the value of ARCH_FORCE_MAX_ORDER will be able to do so but they won't be mislead by the bogus ranges. [rppt@kernel.org: untweak ARCH_FORCE_MAX_ORDER's `range'] Link: https://lkml.kernel.org/r/20230325060828.2662773-13-rppt@kernel.org Link: https://lkml.kernel.org/r/20230324052233.2654090-13-rppt@kernel.org Signed-off-by: Mike Rapoport (IBM) Acked-by: Kirill A. Shutemov Reviewed-by: Zi Yan Cc: Arnd Bergmann Cc: Catalin Marinas Cc: Christophe Leroy Cc: David Miller Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Guo Ren Cc: John Paul Adrian Glaubitz Cc: Max Filippov Cc: Michael Ellerman Cc: Rich Felker Cc: "Russell King (Oracle)" Cc: Will Deacon Cc: Yoshinori Sato Signed-off-by: Andrew Morton --- arch/sh/mm/Kconfig | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/sh') diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig index 238b2772751e..511c17aede4a 100644 --- a/arch/sh/mm/Kconfig +++ b/arch/sh/mm/Kconfig @@ -20,11 +20,8 @@ config PAGE_OFFSET config ARCH_FORCE_MAX_ORDER int "Order of maximal physically contiguous allocations" - range 8 63 if PAGE_SIZE_16KB default "8" if PAGE_SIZE_16KB - range 6 63 if PAGE_SIZE_64KB default "6" if PAGE_SIZE_64KB - range 10 63 default "13" if !MMU default "10" help -- cgit v1.2.3