diff options
Diffstat (limited to '0001-mm-CONFIG_NR_ZONES_EXTENDED.patch')
| -rw-r--r-- | 0001-mm-CONFIG_NR_ZONES_EXTENDED.patch | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/0001-mm-CONFIG_NR_ZONES_EXTENDED.patch b/0001-mm-CONFIG_NR_ZONES_EXTENDED.patch new file mode 100644 index 000000000..44ef3662b --- /dev/null +++ b/0001-mm-CONFIG_NR_ZONES_EXTENDED.patch @@ -0,0 +1,173 @@ +From 8b368e8e961944105945fbe36f3f264252bfd19a Mon Sep 17 00:00:00 2001 +From: Dan Williams <dan.j.williams@intel.com> +Date: Thu, 25 Feb 2016 01:02:30 +0000 +Subject: [PATCH] mm: CONFIG_NR_ZONES_EXTENDED + +ZONE_DEVICE (merged in 4.3) and ZONE_CMA (proposed) are examples of new mm +zones that are bumping up against the current maximum limit of 4 zones, +i.e. 2 bits in page->flags. When adding a zone this equation still needs +to be satisified: + + SECTIONS_WIDTH + ZONES_WIDTH + NODES_SHIFT + LAST_CPUPID_SHIFT + <= BITS_PER_LONG - NR_PAGEFLAGS + +ZONE_DEVICE currently tries to satisfy this equation by requiring that +ZONE_DMA be disabled, but this is untenable given generic kernels want to +support ZONE_DEVICE and ZONE_DMA simultaneously. ZONE_CMA would like to +increase the amount of memory covered per section, but that limits the +minimum granularity at which consecutive memory ranges can be added via +devm_memremap_pages(). + +The trade-off of what is acceptable to sacrifice depends heavily on the +platform. For example, ZONE_CMA is targeted for 32-bit platforms where +page->flags is constrained, but those platforms likely do not care about +the minimum granularity of memory hotplug. A big iron machine with 1024 +numa nodes can likely sacrifice ZONE_DMA where a general purpose +distribution kernel can not. + +CONFIG_NR_ZONES_EXTENDED is a configuration symbol that gets selected when +the number of configured zones exceeds 4. It documents the configuration +symbols and definitions that get modified when ZONES_WIDTH is greater than +2. + +For now, it steals a bit from NODES_SHIFT. Later on it can be used to +document the definitions that get modified when a 32-bit configuration +wants more zone bits. + +Note that GFP_ZONE_TABLE poses an interesting constraint since +include/linux/gfp.h gets included by the 32-bit portion of a 64-bit build. +We need to be careful to only build the table for zones that have a +corresponding gfp_t flag. GFP_ZONES_SHIFT is introduced for this purpose. +This patch does not attempt to solve the problem of adding a new zone +that also has a corresponding GFP_ flag. + +Link: https://bugzilla.kernel.org/show_bug.cgi?id=110931 +Fixes: 033fbae988fc ("mm: ZONE_DEVICE for "device memory"") +Signed-off-by: Dan Williams <dan.j.williams@intel.com> +Reported-by: Mark <markk@clara.co.uk> +Cc: Mel Gorman <mgorman@suse.de> +Cc: Rik van Riel <riel@redhat.com> +Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> +Cc: Dave Hansen <dave.hansen@linux.intel.com> +Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> +Signed-off-by: Andrew Morton <akpm@linux-foundation.org> +--- + arch/x86/Kconfig | 6 ++++-- + include/linux/gfp.h | 33 ++++++++++++++++++++------------- + include/linux/page-flags-layout.h | 2 ++ + mm/Kconfig | 7 +++++-- + 4 files changed, 31 insertions(+), 17 deletions(-) + +diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig +index 3fef519..b94704a 100644 +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -1409,8 +1409,10 @@ config NUMA_EMU + + config NODES_SHIFT + int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP +- range 1 10 +- default "10" if MAXSMP ++ range 1 10 if !NR_ZONES_EXTENDED ++ range 1 9 if NR_ZONES_EXTENDED ++ default "10" if MAXSMP && !NR_ZONES_EXTENDED ++ default "9" if MAXSMP && NR_ZONES_EXTENDED + default "6" if X86_64 + default "3" + depends on NEED_MULTIPLE_NODES +diff --git a/include/linux/gfp.h b/include/linux/gfp.h +index af1f2b2..d201d8a 100644 +--- a/include/linux/gfp.h ++++ b/include/linux/gfp.h +@@ -329,22 +329,29 @@ static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags) + * 0xe => BAD (MOVABLE+DMA32+HIGHMEM) + * 0xf => BAD (MOVABLE+DMA32+HIGHMEM+DMA) + * +- * ZONES_SHIFT must be <= 2 on 32 bit platforms. ++ * GFP_ZONES_SHIFT must be <= 2 on 32 bit platforms. + */ + +-#if 16 * ZONES_SHIFT > BITS_PER_LONG +-#error ZONES_SHIFT too large to create GFP_ZONE_TABLE integer ++#if defined(CONFIG_ZONE_DEVICE) && (MAX_NR_ZONES-1) <= 4 ++/* ZONE_DEVICE is not a valid GFP zone specifier */ ++#define GFP_ZONES_SHIFT 2 ++#else ++#define GFP_ZONES_SHIFT ZONES_SHIFT ++#endif ++ ++#if 16 * GFP_ZONES_SHIFT > BITS_PER_LONG ++#error GFP_ZONES_SHIFT too large to create GFP_ZONE_TABLE integer + #endif + + #define GFP_ZONE_TABLE ( \ +- (ZONE_NORMAL << 0 * ZONES_SHIFT) \ +- | (OPT_ZONE_DMA << ___GFP_DMA * ZONES_SHIFT) \ +- | (OPT_ZONE_HIGHMEM << ___GFP_HIGHMEM * ZONES_SHIFT) \ +- | (OPT_ZONE_DMA32 << ___GFP_DMA32 * ZONES_SHIFT) \ +- | (ZONE_NORMAL << ___GFP_MOVABLE * ZONES_SHIFT) \ +- | (OPT_ZONE_DMA << (___GFP_MOVABLE | ___GFP_DMA) * ZONES_SHIFT) \ +- | (ZONE_MOVABLE << (___GFP_MOVABLE | ___GFP_HIGHMEM) * ZONES_SHIFT) \ +- | (OPT_ZONE_DMA32 << (___GFP_MOVABLE | ___GFP_DMA32) * ZONES_SHIFT) \ ++ (ZONE_NORMAL << 0 * GFP_ZONES_SHIFT) \ ++ | (OPT_ZONE_DMA << ___GFP_DMA * GFP_ZONES_SHIFT) \ ++ | (OPT_ZONE_HIGHMEM << ___GFP_HIGHMEM * GFP_ZONES_SHIFT) \ ++ | (OPT_ZONE_DMA32 << ___GFP_DMA32 * GFP_ZONES_SHIFT) \ ++ | (ZONE_NORMAL << ___GFP_MOVABLE * GFP_ZONES_SHIFT) \ ++ | (OPT_ZONE_DMA << (___GFP_MOVABLE | ___GFP_DMA) * GFP_ZONES_SHIFT) \ ++ | (ZONE_MOVABLE << (___GFP_MOVABLE | ___GFP_HIGHMEM) * GFP_ZONES_SHIFT) \ ++ | (OPT_ZONE_DMA32 << (___GFP_MOVABLE | ___GFP_DMA32) * GFP_ZONES_SHIFT) \ + ) + + /* +@@ -369,8 +376,8 @@ static inline enum zone_type gfp_zone(gfp_t flags) + enum zone_type z; + int bit = (__force int) (flags & GFP_ZONEMASK); + +- z = (GFP_ZONE_TABLE >> (bit * ZONES_SHIFT)) & +- ((1 << ZONES_SHIFT) - 1); ++ z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) & ++ ((1 << GFP_ZONES_SHIFT) - 1); + VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1); + return z; + } +diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h +index da52366..77b078c 100644 +--- a/include/linux/page-flags-layout.h ++++ b/include/linux/page-flags-layout.h +@@ -17,6 +17,8 @@ + #define ZONES_SHIFT 1 + #elif MAX_NR_ZONES <= 4 + #define ZONES_SHIFT 2 ++#elif MAX_NR_ZONES <= 8 ++#define ZONES_SHIFT 3 + #else + #error ZONES_SHIFT -- too many zones configured adjust calculation + #endif +diff --git a/mm/Kconfig b/mm/Kconfig +index 031a329..7826216 100644 +--- a/mm/Kconfig ++++ b/mm/Kconfig +@@ -652,8 +652,6 @@ config IDLE_PAGE_TRACKING + + config ZONE_DEVICE + bool "Device memory (pmem, etc...) hotplug support" +- default !ZONE_DMA +- depends on !ZONE_DMA + depends on MEMORY_HOTPLUG + depends on MEMORY_HOTREMOVE + depends on X86_64 #arch_add_memory() comprehends device memory +@@ -667,5 +665,10 @@ config ZONE_DEVICE + + If FS_DAX is enabled, then say Y. + ++config NR_ZONES_EXTENDED ++ bool ++ default n if !64BIT ++ default y if ZONE_DEVICE && ZONE_DMA && ZONE_DMA32 ++ + config FRAME_VECTOR + bool +-- +2.5.0 + |