| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef PAGE_FLAGS_LAYOUT_H |
| #define PAGE_FLAGS_LAYOUT_H |
| |
| #include <linux/numa.h> |
| #include <generated/bounds.h> |
| |
| /* |
| * When a memory allocation must conform to specific limitations (such |
| * as being suitable for DMA) the caller will pass in hints to the |
| * allocator in the gfp_mask, in the zone modifier bits. These bits |
| * are used to select a priority ordered list of memory zones which |
| * match the requested limits. See gfp_zone() in include/linux/gfp.h |
| */ |
| #if MAX_NR_ZONES < 2 |
| #define ZONES_SHIFT 0 |
| #elif MAX_NR_ZONES <= 2 |
| #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 |
| |
| #ifdef CONFIG_SPARSEMEM |
| #include <asm/sparsemem.h> |
| |
| /* SECTION_SHIFT #bits space required to store a section # */ |
| #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS) |
| |
| #endif /* CONFIG_SPARSEMEM */ |
| |
| #ifndef BUILD_VDSO32_64 |
| /* |
| * page->flags layout: |
| * |
| * There are five possibilities for how page->flags get laid out. The first |
| * pair is for the normal case without sparsemem. The second pair is for |
| * sparsemem when there is plenty of space for node and section information. |
| * The last is when there is insufficient space in page->flags and a separate |
| * lookup is necessary. |
| * |
| * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS | |
| * " plus space for last_cpupid: | NODE | ZONE | LAST_CPUPID ... | FLAGS | |
| * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS | |
| * " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS | |
| * classic sparse no space for node: | SECTION | ZONE | ... | FLAGS | |
| */ |
| #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) |
| #define SECTIONS_WIDTH SECTIONS_SHIFT |
| #else |
| #define SECTIONS_WIDTH 0 |
| #endif |
| |
| #define ZONES_WIDTH ZONES_SHIFT |
| |
| #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS |
| #define NODES_WIDTH NODES_SHIFT |
| #else |
| #ifdef CONFIG_SPARSEMEM_VMEMMAP |
| #error "Vmemmap: No space for nodes field in page flags" |
| #endif |
| #define NODES_WIDTH 0 |
| #endif |
| |
| #ifdef CONFIG_NUMA_BALANCING |
| #define LAST__PID_SHIFT 8 |
| #define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1) |
| |
| #define LAST__CPU_SHIFT NR_CPUS_BITS |
| #define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1) |
| |
| #define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT) |
| #else |
| #define LAST_CPUPID_SHIFT 0 |
| #endif |
| |
| #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) |
| #define KASAN_TAG_WIDTH 8 |
| #else |
| #define KASAN_TAG_WIDTH 0 |
| #endif |
| |
| #if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT+KASAN_TAG_WIDTH \ |
| <= BITS_PER_LONG - NR_PAGEFLAGS |
| #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT |
| #else |
| #define LAST_CPUPID_WIDTH 0 |
| #endif |
| |
| #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH+LAST_CPUPID_WIDTH+KASAN_TAG_WIDTH \ |
| > BITS_PER_LONG - NR_PAGEFLAGS |
| #error "Not enough bits in page flags" |
| #endif |
| |
| /* |
| * We are going to use the flags for the page to node mapping if its in |
| * there. This includes the case where there is no node, so it is implicit. |
| * Note that this #define MUST have a value so that it can be tested with |
| * the IS_ENABLED() macro. |
| */ |
| #if !(NODES_WIDTH > 0 || NODES_SHIFT == 0) |
| #define NODE_NOT_IN_PAGE_FLAGS 1 |
| #endif |
| |
| #if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0 |
| #define LAST_CPUPID_NOT_IN_PAGE_FLAGS |
| #endif |
| |
| #endif |
| #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ |