![Linus Torvalds](/assets/img/avatar_default.png)
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
427 lines
13 KiB
C
427 lines
13 KiB
C
#ifndef _LINUX_MMZONE_H
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#define _LINUX_MMZONE_H
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#ifdef __KERNEL__
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#ifndef __ASSEMBLY__
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#include <linux/config.h>
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#include <linux/spinlock.h>
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#include <linux/list.h>
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#include <linux/wait.h>
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#include <linux/cache.h>
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#include <linux/threads.h>
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#include <linux/numa.h>
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#include <linux/init.h>
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#include <asm/atomic.h>
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/* Free memory management - zoned buddy allocator. */
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#ifndef CONFIG_FORCE_MAX_ZONEORDER
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#define MAX_ORDER 11
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#else
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#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
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#endif
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struct free_area {
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struct list_head free_list;
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unsigned long nr_free;
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};
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struct pglist_data;
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/*
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* zone->lock and zone->lru_lock are two of the hottest locks in the kernel.
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* So add a wild amount of padding here to ensure that they fall into separate
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* cachelines. There are very few zone structures in the machine, so space
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* consumption is not a concern here.
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*/
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#if defined(CONFIG_SMP)
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struct zone_padding {
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char x[0];
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} ____cacheline_maxaligned_in_smp;
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#define ZONE_PADDING(name) struct zone_padding name;
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#else
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#define ZONE_PADDING(name)
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#endif
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struct per_cpu_pages {
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int count; /* number of pages in the list */
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int low; /* low watermark, refill needed */
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int high; /* high watermark, emptying needed */
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int batch; /* chunk size for buddy add/remove */
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struct list_head list; /* the list of pages */
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};
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struct per_cpu_pageset {
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struct per_cpu_pages pcp[2]; /* 0: hot. 1: cold */
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#ifdef CONFIG_NUMA
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unsigned long numa_hit; /* allocated in intended node */
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unsigned long numa_miss; /* allocated in non intended node */
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unsigned long numa_foreign; /* was intended here, hit elsewhere */
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unsigned long interleave_hit; /* interleaver prefered this zone */
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unsigned long local_node; /* allocation from local node */
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unsigned long other_node; /* allocation from other node */
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#endif
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} ____cacheline_aligned_in_smp;
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#define ZONE_DMA 0
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#define ZONE_NORMAL 1
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#define ZONE_HIGHMEM 2
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#define MAX_NR_ZONES 3 /* Sync this with ZONES_SHIFT */
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#define ZONES_SHIFT 2 /* ceil(log2(MAX_NR_ZONES)) */
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/*
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* When a memory allocation must conform to specific limitations (such
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* as being suitable for DMA) the caller will pass in hints to the
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* allocator in the gfp_mask, in the zone modifier bits. These bits
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* are used to select a priority ordered list of memory zones which
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* match the requested limits. GFP_ZONEMASK defines which bits within
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* the gfp_mask should be considered as zone modifiers. Each valid
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* combination of the zone modifier bits has a corresponding list
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* of zones (in node_zonelists). Thus for two zone modifiers there
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* will be a maximum of 4 (2 ** 2) zonelists, for 3 modifiers there will
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* be 8 (2 ** 3) zonelists. GFP_ZONETYPES defines the number of possible
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* combinations of zone modifiers in "zone modifier space".
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*/
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#define GFP_ZONEMASK 0x03
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/*
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* As an optimisation any zone modifier bits which are only valid when
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* no other zone modifier bits are set (loners) should be placed in
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* the highest order bits of this field. This allows us to reduce the
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* extent of the zonelists thus saving space. For example in the case
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* of three zone modifier bits, we could require up to eight zonelists.
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* If the left most zone modifier is a "loner" then the highest valid
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* zonelist would be four allowing us to allocate only five zonelists.
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* Use the first form when the left most bit is not a "loner", otherwise
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* use the second.
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*/
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/* #define GFP_ZONETYPES (GFP_ZONEMASK + 1) */ /* Non-loner */
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#define GFP_ZONETYPES ((GFP_ZONEMASK + 1) / 2 + 1) /* Loner */
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/*
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* On machines where it is needed (eg PCs) we divide physical memory
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* into multiple physical zones. On a PC we have 3 zones:
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*
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* ZONE_DMA < 16 MB ISA DMA capable memory
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* ZONE_NORMAL 16-896 MB direct mapped by the kernel
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* ZONE_HIGHMEM > 896 MB only page cache and user processes
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*/
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struct zone {
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/* Fields commonly accessed by the page allocator */
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unsigned long free_pages;
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unsigned long pages_min, pages_low, pages_high;
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/*
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* We don't know if the memory that we're going to allocate will be freeable
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* or/and it will be released eventually, so to avoid totally wasting several
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* GB of ram we must reserve some of the lower zone memory (otherwise we risk
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* to run OOM on the lower zones despite there's tons of freeable ram
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* on the higher zones). This array is recalculated at runtime if the
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* sysctl_lowmem_reserve_ratio sysctl changes.
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*/
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unsigned long lowmem_reserve[MAX_NR_ZONES];
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struct per_cpu_pageset pageset[NR_CPUS];
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/*
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* free areas of different sizes
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*/
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spinlock_t lock;
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struct free_area free_area[MAX_ORDER];
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ZONE_PADDING(_pad1_)
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/* Fields commonly accessed by the page reclaim scanner */
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spinlock_t lru_lock;
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struct list_head active_list;
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struct list_head inactive_list;
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unsigned long nr_scan_active;
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unsigned long nr_scan_inactive;
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unsigned long nr_active;
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unsigned long nr_inactive;
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unsigned long pages_scanned; /* since last reclaim */
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int all_unreclaimable; /* All pages pinned */
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/*
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* prev_priority holds the scanning priority for this zone. It is
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* defined as the scanning priority at which we achieved our reclaim
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* target at the previous try_to_free_pages() or balance_pgdat()
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* invokation.
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*
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* We use prev_priority as a measure of how much stress page reclaim is
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* under - it drives the swappiness decision: whether to unmap mapped
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* pages.
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*
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* temp_priority is used to remember the scanning priority at which
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* this zone was successfully refilled to free_pages == pages_high.
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*
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* Access to both these fields is quite racy even on uniprocessor. But
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* it is expected to average out OK.
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*/
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int temp_priority;
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int prev_priority;
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ZONE_PADDING(_pad2_)
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/* Rarely used or read-mostly fields */
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/*
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* wait_table -- the array holding the hash table
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* wait_table_size -- the size of the hash table array
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* wait_table_bits -- wait_table_size == (1 << wait_table_bits)
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*
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* The purpose of all these is to keep track of the people
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* waiting for a page to become available and make them
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* runnable again when possible. The trouble is that this
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* consumes a lot of space, especially when so few things
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* wait on pages at a given time. So instead of using
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* per-page waitqueues, we use a waitqueue hash table.
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*
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* The bucket discipline is to sleep on the same queue when
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* colliding and wake all in that wait queue when removing.
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* When something wakes, it must check to be sure its page is
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* truly available, a la thundering herd. The cost of a
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* collision is great, but given the expected load of the
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* table, they should be so rare as to be outweighed by the
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* benefits from the saved space.
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*
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* __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the
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* primary users of these fields, and in mm/page_alloc.c
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* free_area_init_core() performs the initialization of them.
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*/
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wait_queue_head_t * wait_table;
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unsigned long wait_table_size;
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unsigned long wait_table_bits;
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/*
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* Discontig memory support fields.
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*/
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struct pglist_data *zone_pgdat;
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struct page *zone_mem_map;
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/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
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unsigned long zone_start_pfn;
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unsigned long spanned_pages; /* total size, including holes */
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unsigned long present_pages; /* amount of memory (excluding holes) */
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/*
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* rarely used fields:
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*/
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char *name;
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} ____cacheline_maxaligned_in_smp;
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/*
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* The "priority" of VM scanning is how much of the queues we will scan in one
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* go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
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* queues ("queue_length >> 12") during an aging round.
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*/
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#define DEF_PRIORITY 12
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/*
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* One allocation request operates on a zonelist. A zonelist
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* is a list of zones, the first one is the 'goal' of the
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* allocation, the other zones are fallback zones, in decreasing
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* priority.
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*
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* Right now a zonelist takes up less than a cacheline. We never
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* modify it apart from boot-up, and only a few indices are used,
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* so despite the zonelist table being relatively big, the cache
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* footprint of this construct is very small.
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*/
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struct zonelist {
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struct zone *zones[MAX_NUMNODES * MAX_NR_ZONES + 1]; // NULL delimited
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};
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/*
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* The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM
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* (mostly NUMA machines?) to denote a higher-level memory zone than the
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* zone denotes.
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*
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* On NUMA machines, each NUMA node would have a pg_data_t to describe
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* it's memory layout.
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*
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* Memory statistics and page replacement data structures are maintained on a
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* per-zone basis.
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*/
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struct bootmem_data;
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typedef struct pglist_data {
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struct zone node_zones[MAX_NR_ZONES];
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struct zonelist node_zonelists[GFP_ZONETYPES];
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int nr_zones;
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struct page *node_mem_map;
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struct bootmem_data *bdata;
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unsigned long node_start_pfn;
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unsigned long node_present_pages; /* total number of physical pages */
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unsigned long node_spanned_pages; /* total size of physical page
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range, including holes */
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int node_id;
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struct pglist_data *pgdat_next;
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wait_queue_head_t kswapd_wait;
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struct task_struct *kswapd;
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int kswapd_max_order;
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} pg_data_t;
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#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
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#define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)
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extern struct pglist_data *pgdat_list;
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void __get_zone_counts(unsigned long *active, unsigned long *inactive,
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unsigned long *free, struct pglist_data *pgdat);
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void get_zone_counts(unsigned long *active, unsigned long *inactive,
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unsigned long *free);
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void build_all_zonelists(void);
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void wakeup_kswapd(struct zone *zone, int order);
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int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
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int alloc_type, int can_try_harder, int gfp_high);
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#ifdef CONFIG_HAVE_MEMORY_PRESENT
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void memory_present(int nid, unsigned long start, unsigned long end);
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#else
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static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
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#endif
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#ifdef CONFIG_NEED_NODE_MEMMAP_SIZE
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unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
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#endif
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/*
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* zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
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*/
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#define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones)
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/**
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* for_each_pgdat - helper macro to iterate over all nodes
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* @pgdat - pointer to a pg_data_t variable
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*
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* Meant to help with common loops of the form
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* pgdat = pgdat_list;
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* while(pgdat) {
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* ...
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* pgdat = pgdat->pgdat_next;
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* }
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*/
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#define for_each_pgdat(pgdat) \
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for (pgdat = pgdat_list; pgdat; pgdat = pgdat->pgdat_next)
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/*
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* next_zone - helper magic for for_each_zone()
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* Thanks to William Lee Irwin III for this piece of ingenuity.
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*/
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static inline struct zone *next_zone(struct zone *zone)
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{
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pg_data_t *pgdat = zone->zone_pgdat;
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if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
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zone++;
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else if (pgdat->pgdat_next) {
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pgdat = pgdat->pgdat_next;
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zone = pgdat->node_zones;
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} else
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zone = NULL;
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return zone;
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}
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/**
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* for_each_zone - helper macro to iterate over all memory zones
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* @zone - pointer to struct zone variable
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*
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* The user only needs to declare the zone variable, for_each_zone
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* fills it in. This basically means for_each_zone() is an
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* easier to read version of this piece of code:
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*
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* for (pgdat = pgdat_list; pgdat; pgdat = pgdat->node_next)
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* for (i = 0; i < MAX_NR_ZONES; ++i) {
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* struct zone * z = pgdat->node_zones + i;
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* ...
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* }
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* }
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*/
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#define for_each_zone(zone) \
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for (zone = pgdat_list->node_zones; zone; zone = next_zone(zone))
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static inline int is_highmem_idx(int idx)
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{
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return (idx == ZONE_HIGHMEM);
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}
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static inline int is_normal_idx(int idx)
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{
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return (idx == ZONE_NORMAL);
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}
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/**
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* is_highmem - helper function to quickly check if a struct zone is a
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* highmem zone or not. This is an attempt to keep references
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* to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
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* @zone - pointer to struct zone variable
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*/
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static inline int is_highmem(struct zone *zone)
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{
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return zone == zone->zone_pgdat->node_zones + ZONE_HIGHMEM;
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}
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static inline int is_normal(struct zone *zone)
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{
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return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL;
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}
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/* These two functions are used to setup the per zone pages min values */
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struct ctl_table;
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struct file;
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int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *,
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void __user *, size_t *, loff_t *);
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extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
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int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *,
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void __user *, size_t *, loff_t *);
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#include <linux/topology.h>
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/* Returns the number of the current Node. */
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#define numa_node_id() (cpu_to_node(_smp_processor_id()))
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#ifndef CONFIG_DISCONTIGMEM
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extern struct pglist_data contig_page_data;
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#define NODE_DATA(nid) (&contig_page_data)
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#define NODE_MEM_MAP(nid) mem_map
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#define MAX_NODES_SHIFT 1
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#define pfn_to_nid(pfn) (0)
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#else /* CONFIG_DISCONTIGMEM */
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#include <asm/mmzone.h>
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#if BITS_PER_LONG == 32 || defined(ARCH_HAS_ATOMIC_UNSIGNED)
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/*
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* with 32 bit page->flags field, we reserve 8 bits for node/zone info.
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* there are 3 zones (2 bits) and this leaves 8-2=6 bits for nodes.
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*/
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#define MAX_NODES_SHIFT 6
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#elif BITS_PER_LONG == 64
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/*
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* with 64 bit flags field, there's plenty of room.
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*/
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#define MAX_NODES_SHIFT 10
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#endif
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#endif /* !CONFIG_DISCONTIGMEM */
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#if NODES_SHIFT > MAX_NODES_SHIFT
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#error NODES_SHIFT > MAX_NODES_SHIFT
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#endif
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/* There are currently 3 zones: DMA, Normal & Highmem, thus we need 2 bits */
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#define MAX_ZONES_SHIFT 2
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#if ZONES_SHIFT > MAX_ZONES_SHIFT
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#error ZONES_SHIFT > MAX_ZONES_SHIFT
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#endif
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#endif /* !__ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _LINUX_MMZONE_H */
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