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f09f1243ca
linux/mm.h provides offset_in_page() macro. Let's use already predefined macro instead of (addr & ~PAGE_MASK). Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2295 lines
66 KiB
C
2295 lines
66 KiB
C
/*
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* mm/percpu.c - percpu memory allocator
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*
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* Copyright (C) 2009 SUSE Linux Products GmbH
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* Copyright (C) 2009 Tejun Heo <tj@kernel.org>
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*
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* This file is released under the GPLv2.
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*
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* This is percpu allocator which can handle both static and dynamic
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* areas. Percpu areas are allocated in chunks. Each chunk is
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* consisted of boot-time determined number of units and the first
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* chunk is used for static percpu variables in the kernel image
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* (special boot time alloc/init handling necessary as these areas
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* need to be brought up before allocation services are running).
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* Unit grows as necessary and all units grow or shrink in unison.
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* When a chunk is filled up, another chunk is allocated.
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*
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* c0 c1 c2
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* ------------------- ------------------- ------------
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* | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
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* ------------------- ...... ------------------- .... ------------
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*
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* Allocation is done in offset-size areas of single unit space. Ie,
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* an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
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* c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to
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* cpus. On NUMA, the mapping can be non-linear and even sparse.
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* Percpu access can be done by configuring percpu base registers
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* according to cpu to unit mapping and pcpu_unit_size.
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*
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* There are usually many small percpu allocations many of them being
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* as small as 4 bytes. The allocator organizes chunks into lists
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* according to free size and tries to allocate from the fullest one.
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* Each chunk keeps the maximum contiguous area size hint which is
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* guaranteed to be equal to or larger than the maximum contiguous
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* area in the chunk. This helps the allocator not to iterate the
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* chunk maps unnecessarily.
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*
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* Allocation state in each chunk is kept using an array of integers
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* on chunk->map. A positive value in the map represents a free
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* region and negative allocated. Allocation inside a chunk is done
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* by scanning this map sequentially and serving the first matching
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* entry. This is mostly copied from the percpu_modalloc() allocator.
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* Chunks can be determined from the address using the index field
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* in the page struct. The index field contains a pointer to the chunk.
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*
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* To use this allocator, arch code should do the followings.
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*
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* - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
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* regular address to percpu pointer and back if they need to be
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* different from the default
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*
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* - use pcpu_setup_first_chunk() during percpu area initialization to
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* setup the first chunk containing the kernel static percpu area
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*/
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#include <linux/bitmap.h>
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#include <linux/bootmem.h>
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#include <linux/err.h>
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#include <linux/list.h>
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#include <linux/log2.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/percpu.h>
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#include <linux/pfn.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/vmalloc.h>
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#include <linux/workqueue.h>
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#include <linux/kmemleak.h>
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#include <asm/cacheflush.h>
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#include <asm/sections.h>
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#include <asm/tlbflush.h>
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#include <asm/io.h>
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#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
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#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
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#define PCPU_ATOMIC_MAP_MARGIN_LOW 32
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#define PCPU_ATOMIC_MAP_MARGIN_HIGH 64
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#define PCPU_EMPTY_POP_PAGES_LOW 2
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#define PCPU_EMPTY_POP_PAGES_HIGH 4
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#ifdef CONFIG_SMP
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/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
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#ifndef __addr_to_pcpu_ptr
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#define __addr_to_pcpu_ptr(addr) \
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(void __percpu *)((unsigned long)(addr) - \
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(unsigned long)pcpu_base_addr + \
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(unsigned long)__per_cpu_start)
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#endif
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#ifndef __pcpu_ptr_to_addr
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#define __pcpu_ptr_to_addr(ptr) \
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(void __force *)((unsigned long)(ptr) + \
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(unsigned long)pcpu_base_addr - \
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(unsigned long)__per_cpu_start)
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#endif
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#else /* CONFIG_SMP */
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/* on UP, it's always identity mapped */
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#define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
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#define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
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#endif /* CONFIG_SMP */
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struct pcpu_chunk {
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struct list_head list; /* linked to pcpu_slot lists */
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int free_size; /* free bytes in the chunk */
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int contig_hint; /* max contiguous size hint */
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void *base_addr; /* base address of this chunk */
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int map_used; /* # of map entries used before the sentry */
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int map_alloc; /* # of map entries allocated */
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int *map; /* allocation map */
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struct work_struct map_extend_work;/* async ->map[] extension */
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void *data; /* chunk data */
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int first_free; /* no free below this */
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bool immutable; /* no [de]population allowed */
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int nr_populated; /* # of populated pages */
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unsigned long populated[]; /* populated bitmap */
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};
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static int pcpu_unit_pages __read_mostly;
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static int pcpu_unit_size __read_mostly;
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static int pcpu_nr_units __read_mostly;
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static int pcpu_atom_size __read_mostly;
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static int pcpu_nr_slots __read_mostly;
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static size_t pcpu_chunk_struct_size __read_mostly;
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/* cpus with the lowest and highest unit addresses */
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static unsigned int pcpu_low_unit_cpu __read_mostly;
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static unsigned int pcpu_high_unit_cpu __read_mostly;
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/* the address of the first chunk which starts with the kernel static area */
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void *pcpu_base_addr __read_mostly;
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EXPORT_SYMBOL_GPL(pcpu_base_addr);
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static const int *pcpu_unit_map __read_mostly; /* cpu -> unit */
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const unsigned long *pcpu_unit_offsets __read_mostly; /* cpu -> unit offset */
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/* group information, used for vm allocation */
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static int pcpu_nr_groups __read_mostly;
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static const unsigned long *pcpu_group_offsets __read_mostly;
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static const size_t *pcpu_group_sizes __read_mostly;
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/*
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* The first chunk which always exists. Note that unlike other
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* chunks, this one can be allocated and mapped in several different
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* ways and thus often doesn't live in the vmalloc area.
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*/
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static struct pcpu_chunk *pcpu_first_chunk;
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/*
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* Optional reserved chunk. This chunk reserves part of the first
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* chunk and serves it for reserved allocations. The amount of
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* reserved offset is in pcpu_reserved_chunk_limit. When reserved
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* area doesn't exist, the following variables contain NULL and 0
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* respectively.
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*/
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static struct pcpu_chunk *pcpu_reserved_chunk;
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static int pcpu_reserved_chunk_limit;
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static DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
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static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop */
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static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
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/*
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* The number of empty populated pages, protected by pcpu_lock. The
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* reserved chunk doesn't contribute to the count.
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*/
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static int pcpu_nr_empty_pop_pages;
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/*
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* Balance work is used to populate or destroy chunks asynchronously. We
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* try to keep the number of populated free pages between
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* PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
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* empty chunk.
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*/
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static void pcpu_balance_workfn(struct work_struct *work);
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static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn);
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static bool pcpu_async_enabled __read_mostly;
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static bool pcpu_atomic_alloc_failed;
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static void pcpu_schedule_balance_work(void)
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{
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if (pcpu_async_enabled)
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schedule_work(&pcpu_balance_work);
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}
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static bool pcpu_addr_in_first_chunk(void *addr)
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{
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void *first_start = pcpu_first_chunk->base_addr;
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return addr >= first_start && addr < first_start + pcpu_unit_size;
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}
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static bool pcpu_addr_in_reserved_chunk(void *addr)
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{
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void *first_start = pcpu_first_chunk->base_addr;
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return addr >= first_start &&
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addr < first_start + pcpu_reserved_chunk_limit;
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}
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static int __pcpu_size_to_slot(int size)
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{
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int highbit = fls(size); /* size is in bytes */
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return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
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}
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static int pcpu_size_to_slot(int size)
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{
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if (size == pcpu_unit_size)
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return pcpu_nr_slots - 1;
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return __pcpu_size_to_slot(size);
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}
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static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
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{
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if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
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return 0;
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return pcpu_size_to_slot(chunk->free_size);
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}
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/* set the pointer to a chunk in a page struct */
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static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
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{
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page->index = (unsigned long)pcpu;
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}
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/* obtain pointer to a chunk from a page struct */
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static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
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{
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return (struct pcpu_chunk *)page->index;
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}
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static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
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{
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return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
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}
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static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
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unsigned int cpu, int page_idx)
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{
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return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
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(page_idx << PAGE_SHIFT);
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}
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static void __maybe_unused pcpu_next_unpop(struct pcpu_chunk *chunk,
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int *rs, int *re, int end)
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{
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*rs = find_next_zero_bit(chunk->populated, end, *rs);
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*re = find_next_bit(chunk->populated, end, *rs + 1);
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}
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static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
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int *rs, int *re, int end)
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{
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*rs = find_next_bit(chunk->populated, end, *rs);
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*re = find_next_zero_bit(chunk->populated, end, *rs + 1);
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}
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/*
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* (Un)populated page region iterators. Iterate over (un)populated
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* page regions between @start and @end in @chunk. @rs and @re should
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* be integer variables and will be set to start and end page index of
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* the current region.
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*/
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#define pcpu_for_each_unpop_region(chunk, rs, re, start, end) \
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for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
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(rs) < (re); \
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(rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
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#define pcpu_for_each_pop_region(chunk, rs, re, start, end) \
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for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end)); \
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(rs) < (re); \
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(rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
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/**
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* pcpu_mem_zalloc - allocate memory
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* @size: bytes to allocate
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*
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* Allocate @size bytes. If @size is smaller than PAGE_SIZE,
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* kzalloc() is used; otherwise, vzalloc() is used. The returned
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* memory is always zeroed.
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*
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* CONTEXT:
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* Does GFP_KERNEL allocation.
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*
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* RETURNS:
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* Pointer to the allocated area on success, NULL on failure.
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*/
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static void *pcpu_mem_zalloc(size_t size)
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{
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if (WARN_ON_ONCE(!slab_is_available()))
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return NULL;
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if (size <= PAGE_SIZE)
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return kzalloc(size, GFP_KERNEL);
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else
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return vzalloc(size);
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}
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/**
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* pcpu_mem_free - free memory
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* @ptr: memory to free
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* @size: size of the area
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*
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* Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
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*/
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static void pcpu_mem_free(void *ptr, size_t size)
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{
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if (size <= PAGE_SIZE)
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kfree(ptr);
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else
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vfree(ptr);
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}
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/**
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* pcpu_count_occupied_pages - count the number of pages an area occupies
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* @chunk: chunk of interest
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* @i: index of the area in question
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*
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* Count the number of pages chunk's @i'th area occupies. When the area's
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* start and/or end address isn't aligned to page boundary, the straddled
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* page is included in the count iff the rest of the page is free.
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*/
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static int pcpu_count_occupied_pages(struct pcpu_chunk *chunk, int i)
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{
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int off = chunk->map[i] & ~1;
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int end = chunk->map[i + 1] & ~1;
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if (!PAGE_ALIGNED(off) && i > 0) {
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int prev = chunk->map[i - 1];
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if (!(prev & 1) && prev <= round_down(off, PAGE_SIZE))
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off = round_down(off, PAGE_SIZE);
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}
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if (!PAGE_ALIGNED(end) && i + 1 < chunk->map_used) {
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int next = chunk->map[i + 1];
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int nend = chunk->map[i + 2] & ~1;
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if (!(next & 1) && nend >= round_up(end, PAGE_SIZE))
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end = round_up(end, PAGE_SIZE);
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}
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return max_t(int, PFN_DOWN(end) - PFN_UP(off), 0);
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}
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/**
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* pcpu_chunk_relocate - put chunk in the appropriate chunk slot
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* @chunk: chunk of interest
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* @oslot: the previous slot it was on
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*
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* This function is called after an allocation or free changed @chunk.
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* New slot according to the changed state is determined and @chunk is
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* moved to the slot. Note that the reserved chunk is never put on
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* chunk slots.
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*
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* CONTEXT:
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* pcpu_lock.
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*/
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static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
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{
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int nslot = pcpu_chunk_slot(chunk);
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if (chunk != pcpu_reserved_chunk && oslot != nslot) {
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if (oslot < nslot)
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list_move(&chunk->list, &pcpu_slot[nslot]);
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else
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list_move_tail(&chunk->list, &pcpu_slot[nslot]);
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}
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}
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/**
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* pcpu_need_to_extend - determine whether chunk area map needs to be extended
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* @chunk: chunk of interest
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* @is_atomic: the allocation context
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*
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* Determine whether area map of @chunk needs to be extended. If
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* @is_atomic, only the amount necessary for a new allocation is
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* considered; however, async extension is scheduled if the left amount is
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* low. If !@is_atomic, it aims for more empty space. Combined, this
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* ensures that the map is likely to have enough available space to
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* accomodate atomic allocations which can't extend maps directly.
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*
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* CONTEXT:
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* pcpu_lock.
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*
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* RETURNS:
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* New target map allocation length if extension is necessary, 0
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* otherwise.
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*/
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static int pcpu_need_to_extend(struct pcpu_chunk *chunk, bool is_atomic)
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{
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int margin, new_alloc;
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if (is_atomic) {
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margin = 3;
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if (chunk->map_alloc <
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chunk->map_used + PCPU_ATOMIC_MAP_MARGIN_LOW &&
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pcpu_async_enabled)
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schedule_work(&chunk->map_extend_work);
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} else {
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margin = PCPU_ATOMIC_MAP_MARGIN_HIGH;
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}
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if (chunk->map_alloc >= chunk->map_used + margin)
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return 0;
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new_alloc = PCPU_DFL_MAP_ALLOC;
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while (new_alloc < chunk->map_used + margin)
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new_alloc *= 2;
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return new_alloc;
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}
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/**
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* pcpu_extend_area_map - extend area map of a chunk
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* @chunk: chunk of interest
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* @new_alloc: new target allocation length of the area map
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*
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* Extend area map of @chunk to have @new_alloc entries.
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*
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* CONTEXT:
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* Does GFP_KERNEL allocation. Grabs and releases pcpu_lock.
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*
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* RETURNS:
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* 0 on success, -errno on failure.
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*/
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static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
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{
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int *old = NULL, *new = NULL;
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size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
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unsigned long flags;
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new = pcpu_mem_zalloc(new_size);
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if (!new)
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return -ENOMEM;
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/* acquire pcpu_lock and switch to new area map */
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spin_lock_irqsave(&pcpu_lock, flags);
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if (new_alloc <= chunk->map_alloc)
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goto out_unlock;
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old_size = chunk->map_alloc * sizeof(chunk->map[0]);
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old = chunk->map;
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memcpy(new, old, old_size);
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chunk->map_alloc = new_alloc;
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chunk->map = new;
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new = NULL;
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out_unlock:
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spin_unlock_irqrestore(&pcpu_lock, flags);
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/*
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* pcpu_mem_free() might end up calling vfree() which uses
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* IRQ-unsafe lock and thus can't be called under pcpu_lock.
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*/
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pcpu_mem_free(old, old_size);
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pcpu_mem_free(new, new_size);
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return 0;
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}
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|
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static void pcpu_map_extend_workfn(struct work_struct *work)
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{
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|
struct pcpu_chunk *chunk = container_of(work, struct pcpu_chunk,
|
|
map_extend_work);
|
|
int new_alloc;
|
|
|
|
spin_lock_irq(&pcpu_lock);
|
|
new_alloc = pcpu_need_to_extend(chunk, false);
|
|
spin_unlock_irq(&pcpu_lock);
|
|
|
|
if (new_alloc)
|
|
pcpu_extend_area_map(chunk, new_alloc);
|
|
}
|
|
|
|
/**
|
|
* pcpu_fit_in_area - try to fit the requested allocation in a candidate area
|
|
* @chunk: chunk the candidate area belongs to
|
|
* @off: the offset to the start of the candidate area
|
|
* @this_size: the size of the candidate area
|
|
* @size: the size of the target allocation
|
|
* @align: the alignment of the target allocation
|
|
* @pop_only: only allocate from already populated region
|
|
*
|
|
* We're trying to allocate @size bytes aligned at @align. @chunk's area
|
|
* at @off sized @this_size is a candidate. This function determines
|
|
* whether the target allocation fits in the candidate area and returns the
|
|
* number of bytes to pad after @off. If the target area doesn't fit, -1
|
|
* is returned.
|
|
*
|
|
* If @pop_only is %true, this function only considers the already
|
|
* populated part of the candidate area.
|
|
*/
|
|
static int pcpu_fit_in_area(struct pcpu_chunk *chunk, int off, int this_size,
|
|
int size, int align, bool pop_only)
|
|
{
|
|
int cand_off = off;
|
|
|
|
while (true) {
|
|
int head = ALIGN(cand_off, align) - off;
|
|
int page_start, page_end, rs, re;
|
|
|
|
if (this_size < head + size)
|
|
return -1;
|
|
|
|
if (!pop_only)
|
|
return head;
|
|
|
|
/*
|
|
* If the first unpopulated page is beyond the end of the
|
|
* allocation, the whole allocation is populated;
|
|
* otherwise, retry from the end of the unpopulated area.
|
|
*/
|
|
page_start = PFN_DOWN(head + off);
|
|
page_end = PFN_UP(head + off + size);
|
|
|
|
rs = page_start;
|
|
pcpu_next_unpop(chunk, &rs, &re, PFN_UP(off + this_size));
|
|
if (rs >= page_end)
|
|
return head;
|
|
cand_off = re * PAGE_SIZE;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* pcpu_alloc_area - allocate area from a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @size: wanted size in bytes
|
|
* @align: wanted align
|
|
* @pop_only: allocate only from the populated area
|
|
* @occ_pages_p: out param for the number of pages the area occupies
|
|
*
|
|
* Try to allocate @size bytes area aligned at @align from @chunk.
|
|
* Note that this function only allocates the offset. It doesn't
|
|
* populate or map the area.
|
|
*
|
|
* @chunk->map must have at least two free slots.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock.
|
|
*
|
|
* RETURNS:
|
|
* Allocated offset in @chunk on success, -1 if no matching area is
|
|
* found.
|
|
*/
|
|
static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align,
|
|
bool pop_only, int *occ_pages_p)
|
|
{
|
|
int oslot = pcpu_chunk_slot(chunk);
|
|
int max_contig = 0;
|
|
int i, off;
|
|
bool seen_free = false;
|
|
int *p;
|
|
|
|
for (i = chunk->first_free, p = chunk->map + i; i < chunk->map_used; i++, p++) {
|
|
int head, tail;
|
|
int this_size;
|
|
|
|
off = *p;
|
|
if (off & 1)
|
|
continue;
|
|
|
|
this_size = (p[1] & ~1) - off;
|
|
|
|
head = pcpu_fit_in_area(chunk, off, this_size, size, align,
|
|
pop_only);
|
|
if (head < 0) {
|
|
if (!seen_free) {
|
|
chunk->first_free = i;
|
|
seen_free = true;
|
|
}
|
|
max_contig = max(this_size, max_contig);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If head is small or the previous block is free,
|
|
* merge'em. Note that 'small' is defined as smaller
|
|
* than sizeof(int), which is very small but isn't too
|
|
* uncommon for percpu allocations.
|
|
*/
|
|
if (head && (head < sizeof(int) || !(p[-1] & 1))) {
|
|
*p = off += head;
|
|
if (p[-1] & 1)
|
|
chunk->free_size -= head;
|
|
else
|
|
max_contig = max(*p - p[-1], max_contig);
|
|
this_size -= head;
|
|
head = 0;
|
|
}
|
|
|
|
/* if tail is small, just keep it around */
|
|
tail = this_size - head - size;
|
|
if (tail < sizeof(int)) {
|
|
tail = 0;
|
|
size = this_size - head;
|
|
}
|
|
|
|
/* split if warranted */
|
|
if (head || tail) {
|
|
int nr_extra = !!head + !!tail;
|
|
|
|
/* insert new subblocks */
|
|
memmove(p + nr_extra + 1, p + 1,
|
|
sizeof(chunk->map[0]) * (chunk->map_used - i));
|
|
chunk->map_used += nr_extra;
|
|
|
|
if (head) {
|
|
if (!seen_free) {
|
|
chunk->first_free = i;
|
|
seen_free = true;
|
|
}
|
|
*++p = off += head;
|
|
++i;
|
|
max_contig = max(head, max_contig);
|
|
}
|
|
if (tail) {
|
|
p[1] = off + size;
|
|
max_contig = max(tail, max_contig);
|
|
}
|
|
}
|
|
|
|
if (!seen_free)
|
|
chunk->first_free = i + 1;
|
|
|
|
/* update hint and mark allocated */
|
|
if (i + 1 == chunk->map_used)
|
|
chunk->contig_hint = max_contig; /* fully scanned */
|
|
else
|
|
chunk->contig_hint = max(chunk->contig_hint,
|
|
max_contig);
|
|
|
|
chunk->free_size -= size;
|
|
*p |= 1;
|
|
|
|
*occ_pages_p = pcpu_count_occupied_pages(chunk, i);
|
|
pcpu_chunk_relocate(chunk, oslot);
|
|
return off;
|
|
}
|
|
|
|
chunk->contig_hint = max_contig; /* fully scanned */
|
|
pcpu_chunk_relocate(chunk, oslot);
|
|
|
|
/* tell the upper layer that this chunk has no matching area */
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* pcpu_free_area - free area to a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @freeme: offset of area to free
|
|
* @occ_pages_p: out param for the number of pages the area occupies
|
|
*
|
|
* Free area starting from @freeme to @chunk. Note that this function
|
|
* only modifies the allocation map. It doesn't depopulate or unmap
|
|
* the area.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock.
|
|
*/
|
|
static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme,
|
|
int *occ_pages_p)
|
|
{
|
|
int oslot = pcpu_chunk_slot(chunk);
|
|
int off = 0;
|
|
unsigned i, j;
|
|
int to_free = 0;
|
|
int *p;
|
|
|
|
freeme |= 1; /* we are searching for <given offset, in use> pair */
|
|
|
|
i = 0;
|
|
j = chunk->map_used;
|
|
while (i != j) {
|
|
unsigned k = (i + j) / 2;
|
|
off = chunk->map[k];
|
|
if (off < freeme)
|
|
i = k + 1;
|
|
else if (off > freeme)
|
|
j = k;
|
|
else
|
|
i = j = k;
|
|
}
|
|
BUG_ON(off != freeme);
|
|
|
|
if (i < chunk->first_free)
|
|
chunk->first_free = i;
|
|
|
|
p = chunk->map + i;
|
|
*p = off &= ~1;
|
|
chunk->free_size += (p[1] & ~1) - off;
|
|
|
|
*occ_pages_p = pcpu_count_occupied_pages(chunk, i);
|
|
|
|
/* merge with next? */
|
|
if (!(p[1] & 1))
|
|
to_free++;
|
|
/* merge with previous? */
|
|
if (i > 0 && !(p[-1] & 1)) {
|
|
to_free++;
|
|
i--;
|
|
p--;
|
|
}
|
|
if (to_free) {
|
|
chunk->map_used -= to_free;
|
|
memmove(p + 1, p + 1 + to_free,
|
|
(chunk->map_used - i) * sizeof(chunk->map[0]));
|
|
}
|
|
|
|
chunk->contig_hint = max(chunk->map[i + 1] - chunk->map[i] - 1, chunk->contig_hint);
|
|
pcpu_chunk_relocate(chunk, oslot);
|
|
}
|
|
|
|
static struct pcpu_chunk *pcpu_alloc_chunk(void)
|
|
{
|
|
struct pcpu_chunk *chunk;
|
|
|
|
chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size);
|
|
if (!chunk)
|
|
return NULL;
|
|
|
|
chunk->map = pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC *
|
|
sizeof(chunk->map[0]));
|
|
if (!chunk->map) {
|
|
pcpu_mem_free(chunk, pcpu_chunk_struct_size);
|
|
return NULL;
|
|
}
|
|
|
|
chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
|
|
chunk->map[0] = 0;
|
|
chunk->map[1] = pcpu_unit_size | 1;
|
|
chunk->map_used = 1;
|
|
|
|
INIT_LIST_HEAD(&chunk->list);
|
|
INIT_WORK(&chunk->map_extend_work, pcpu_map_extend_workfn);
|
|
chunk->free_size = pcpu_unit_size;
|
|
chunk->contig_hint = pcpu_unit_size;
|
|
|
|
return chunk;
|
|
}
|
|
|
|
static void pcpu_free_chunk(struct pcpu_chunk *chunk)
|
|
{
|
|
if (!chunk)
|
|
return;
|
|
pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
|
|
pcpu_mem_free(chunk, pcpu_chunk_struct_size);
|
|
}
|
|
|
|
/**
|
|
* pcpu_chunk_populated - post-population bookkeeping
|
|
* @chunk: pcpu_chunk which got populated
|
|
* @page_start: the start page
|
|
* @page_end: the end page
|
|
*
|
|
* Pages in [@page_start,@page_end) have been populated to @chunk. Update
|
|
* the bookkeeping information accordingly. Must be called after each
|
|
* successful population.
|
|
*/
|
|
static void pcpu_chunk_populated(struct pcpu_chunk *chunk,
|
|
int page_start, int page_end)
|
|
{
|
|
int nr = page_end - page_start;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
bitmap_set(chunk->populated, page_start, nr);
|
|
chunk->nr_populated += nr;
|
|
pcpu_nr_empty_pop_pages += nr;
|
|
}
|
|
|
|
/**
|
|
* pcpu_chunk_depopulated - post-depopulation bookkeeping
|
|
* @chunk: pcpu_chunk which got depopulated
|
|
* @page_start: the start page
|
|
* @page_end: the end page
|
|
*
|
|
* Pages in [@page_start,@page_end) have been depopulated from @chunk.
|
|
* Update the bookkeeping information accordingly. Must be called after
|
|
* each successful depopulation.
|
|
*/
|
|
static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk,
|
|
int page_start, int page_end)
|
|
{
|
|
int nr = page_end - page_start;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
bitmap_clear(chunk->populated, page_start, nr);
|
|
chunk->nr_populated -= nr;
|
|
pcpu_nr_empty_pop_pages -= nr;
|
|
}
|
|
|
|
/*
|
|
* Chunk management implementation.
|
|
*
|
|
* To allow different implementations, chunk alloc/free and
|
|
* [de]population are implemented in a separate file which is pulled
|
|
* into this file and compiled together. The following functions
|
|
* should be implemented.
|
|
*
|
|
* pcpu_populate_chunk - populate the specified range of a chunk
|
|
* pcpu_depopulate_chunk - depopulate the specified range of a chunk
|
|
* pcpu_create_chunk - create a new chunk
|
|
* pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
|
|
* pcpu_addr_to_page - translate address to physical address
|
|
* pcpu_verify_alloc_info - check alloc_info is acceptable during init
|
|
*/
|
|
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size);
|
|
static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size);
|
|
static struct pcpu_chunk *pcpu_create_chunk(void);
|
|
static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
|
|
static struct page *pcpu_addr_to_page(void *addr);
|
|
static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
|
|
|
|
#ifdef CONFIG_NEED_PER_CPU_KM
|
|
#include "percpu-km.c"
|
|
#else
|
|
#include "percpu-vm.c"
|
|
#endif
|
|
|
|
/**
|
|
* pcpu_chunk_addr_search - determine chunk containing specified address
|
|
* @addr: address for which the chunk needs to be determined.
|
|
*
|
|
* RETURNS:
|
|
* The address of the found chunk.
|
|
*/
|
|
static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
|
|
{
|
|
/* is it in the first chunk? */
|
|
if (pcpu_addr_in_first_chunk(addr)) {
|
|
/* is it in the reserved area? */
|
|
if (pcpu_addr_in_reserved_chunk(addr))
|
|
return pcpu_reserved_chunk;
|
|
return pcpu_first_chunk;
|
|
}
|
|
|
|
/*
|
|
* The address is relative to unit0 which might be unused and
|
|
* thus unmapped. Offset the address to the unit space of the
|
|
* current processor before looking it up in the vmalloc
|
|
* space. Note that any possible cpu id can be used here, so
|
|
* there's no need to worry about preemption or cpu hotplug.
|
|
*/
|
|
addr += pcpu_unit_offsets[raw_smp_processor_id()];
|
|
return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
|
|
}
|
|
|
|
/**
|
|
* pcpu_alloc - the percpu allocator
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
* @reserved: allocate from the reserved chunk if available
|
|
* @gfp: allocation flags
|
|
*
|
|
* Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
|
|
* contain %GFP_KERNEL, the allocation is atomic.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
|
|
gfp_t gfp)
|
|
{
|
|
static int warn_limit = 10;
|
|
struct pcpu_chunk *chunk;
|
|
const char *err;
|
|
bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
|
|
int occ_pages = 0;
|
|
int slot, off, new_alloc, cpu, ret;
|
|
unsigned long flags;
|
|
void __percpu *ptr;
|
|
|
|
/*
|
|
* We want the lowest bit of offset available for in-use/free
|
|
* indicator, so force >= 16bit alignment and make size even.
|
|
*/
|
|
if (unlikely(align < 2))
|
|
align = 2;
|
|
|
|
size = ALIGN(size, 2);
|
|
|
|
if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
|
|
WARN(true, "illegal size (%zu) or align (%zu) for "
|
|
"percpu allocation\n", size, align);
|
|
return NULL;
|
|
}
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
|
|
/* serve reserved allocations from the reserved chunk if available */
|
|
if (reserved && pcpu_reserved_chunk) {
|
|
chunk = pcpu_reserved_chunk;
|
|
|
|
if (size > chunk->contig_hint) {
|
|
err = "alloc from reserved chunk failed";
|
|
goto fail_unlock;
|
|
}
|
|
|
|
while ((new_alloc = pcpu_need_to_extend(chunk, is_atomic))) {
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
if (is_atomic ||
|
|
pcpu_extend_area_map(chunk, new_alloc) < 0) {
|
|
err = "failed to extend area map of reserved chunk";
|
|
goto fail;
|
|
}
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
}
|
|
|
|
off = pcpu_alloc_area(chunk, size, align, is_atomic,
|
|
&occ_pages);
|
|
if (off >= 0)
|
|
goto area_found;
|
|
|
|
err = "alloc from reserved chunk failed";
|
|
goto fail_unlock;
|
|
}
|
|
|
|
restart:
|
|
/* search through normal chunks */
|
|
for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
|
|
list_for_each_entry(chunk, &pcpu_slot[slot], list) {
|
|
if (size > chunk->contig_hint)
|
|
continue;
|
|
|
|
new_alloc = pcpu_need_to_extend(chunk, is_atomic);
|
|
if (new_alloc) {
|
|
if (is_atomic)
|
|
continue;
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
if (pcpu_extend_area_map(chunk,
|
|
new_alloc) < 0) {
|
|
err = "failed to extend area map";
|
|
goto fail;
|
|
}
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
/*
|
|
* pcpu_lock has been dropped, need to
|
|
* restart cpu_slot list walking.
|
|
*/
|
|
goto restart;
|
|
}
|
|
|
|
off = pcpu_alloc_area(chunk, size, align, is_atomic,
|
|
&occ_pages);
|
|
if (off >= 0)
|
|
goto area_found;
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
|
|
/*
|
|
* No space left. Create a new chunk. We don't want multiple
|
|
* tasks to create chunks simultaneously. Serialize and create iff
|
|
* there's still no empty chunk after grabbing the mutex.
|
|
*/
|
|
if (is_atomic)
|
|
goto fail;
|
|
|
|
mutex_lock(&pcpu_alloc_mutex);
|
|
|
|
if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
|
|
chunk = pcpu_create_chunk();
|
|
if (!chunk) {
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
err = "failed to allocate new chunk";
|
|
goto fail;
|
|
}
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
pcpu_chunk_relocate(chunk, -1);
|
|
} else {
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
}
|
|
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
goto restart;
|
|
|
|
area_found:
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
|
|
/* populate if not all pages are already there */
|
|
if (!is_atomic) {
|
|
int page_start, page_end, rs, re;
|
|
|
|
mutex_lock(&pcpu_alloc_mutex);
|
|
|
|
page_start = PFN_DOWN(off);
|
|
page_end = PFN_UP(off + size);
|
|
|
|
pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
|
|
WARN_ON(chunk->immutable);
|
|
|
|
ret = pcpu_populate_chunk(chunk, rs, re);
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
if (ret) {
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
pcpu_free_area(chunk, off, &occ_pages);
|
|
err = "failed to populate";
|
|
goto fail_unlock;
|
|
}
|
|
pcpu_chunk_populated(chunk, rs, re);
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
}
|
|
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
}
|
|
|
|
if (chunk != pcpu_reserved_chunk)
|
|
pcpu_nr_empty_pop_pages -= occ_pages;
|
|
|
|
if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
|
|
pcpu_schedule_balance_work();
|
|
|
|
/* clear the areas and return address relative to base address */
|
|
for_each_possible_cpu(cpu)
|
|
memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
|
|
|
|
ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
|
|
kmemleak_alloc_percpu(ptr, size, gfp);
|
|
return ptr;
|
|
|
|
fail_unlock:
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
fail:
|
|
if (!is_atomic && warn_limit) {
|
|
pr_warning("PERCPU: allocation failed, size=%zu align=%zu atomic=%d, %s\n",
|
|
size, align, is_atomic, err);
|
|
dump_stack();
|
|
if (!--warn_limit)
|
|
pr_info("PERCPU: limit reached, disable warning\n");
|
|
}
|
|
if (is_atomic) {
|
|
/* see the flag handling in pcpu_blance_workfn() */
|
|
pcpu_atomic_alloc_failed = true;
|
|
pcpu_schedule_balance_work();
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* __alloc_percpu_gfp - allocate dynamic percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
* @gfp: allocation flags
|
|
*
|
|
* Allocate zero-filled percpu area of @size bytes aligned at @align. If
|
|
* @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
|
|
* be called from any context but is a lot more likely to fail.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp)
|
|
{
|
|
return pcpu_alloc(size, align, false, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__alloc_percpu_gfp);
|
|
|
|
/**
|
|
* __alloc_percpu - allocate dynamic percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
*
|
|
* Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
|
|
*/
|
|
void __percpu *__alloc_percpu(size_t size, size_t align)
|
|
{
|
|
return pcpu_alloc(size, align, false, GFP_KERNEL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__alloc_percpu);
|
|
|
|
/**
|
|
* __alloc_reserved_percpu - allocate reserved percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
*
|
|
* Allocate zero-filled percpu area of @size bytes aligned at @align
|
|
* from reserved percpu area if arch has set it up; otherwise,
|
|
* allocation is served from the same dynamic area. Might sleep.
|
|
* Might trigger writeouts.
|
|
*
|
|
* CONTEXT:
|
|
* Does GFP_KERNEL allocation.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
|
|
{
|
|
return pcpu_alloc(size, align, true, GFP_KERNEL);
|
|
}
|
|
|
|
/**
|
|
* pcpu_balance_workfn - manage the amount of free chunks and populated pages
|
|
* @work: unused
|
|
*
|
|
* Reclaim all fully free chunks except for the first one.
|
|
*/
|
|
static void pcpu_balance_workfn(struct work_struct *work)
|
|
{
|
|
LIST_HEAD(to_free);
|
|
struct list_head *free_head = &pcpu_slot[pcpu_nr_slots - 1];
|
|
struct pcpu_chunk *chunk, *next;
|
|
int slot, nr_to_pop, ret;
|
|
|
|
/*
|
|
* There's no reason to keep around multiple unused chunks and VM
|
|
* areas can be scarce. Destroy all free chunks except for one.
|
|
*/
|
|
mutex_lock(&pcpu_alloc_mutex);
|
|
spin_lock_irq(&pcpu_lock);
|
|
|
|
list_for_each_entry_safe(chunk, next, free_head, list) {
|
|
WARN_ON(chunk->immutable);
|
|
|
|
/* spare the first one */
|
|
if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
|
|
continue;
|
|
|
|
list_move(&chunk->list, &to_free);
|
|
}
|
|
|
|
spin_unlock_irq(&pcpu_lock);
|
|
|
|
list_for_each_entry_safe(chunk, next, &to_free, list) {
|
|
int rs, re;
|
|
|
|
pcpu_for_each_pop_region(chunk, rs, re, 0, pcpu_unit_pages) {
|
|
pcpu_depopulate_chunk(chunk, rs, re);
|
|
spin_lock_irq(&pcpu_lock);
|
|
pcpu_chunk_depopulated(chunk, rs, re);
|
|
spin_unlock_irq(&pcpu_lock);
|
|
}
|
|
pcpu_destroy_chunk(chunk);
|
|
}
|
|
|
|
/*
|
|
* Ensure there are certain number of free populated pages for
|
|
* atomic allocs. Fill up from the most packed so that atomic
|
|
* allocs don't increase fragmentation. If atomic allocation
|
|
* failed previously, always populate the maximum amount. This
|
|
* should prevent atomic allocs larger than PAGE_SIZE from keeping
|
|
* failing indefinitely; however, large atomic allocs are not
|
|
* something we support properly and can be highly unreliable and
|
|
* inefficient.
|
|
*/
|
|
retry_pop:
|
|
if (pcpu_atomic_alloc_failed) {
|
|
nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH;
|
|
/* best effort anyway, don't worry about synchronization */
|
|
pcpu_atomic_alloc_failed = false;
|
|
} else {
|
|
nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
|
|
pcpu_nr_empty_pop_pages,
|
|
0, PCPU_EMPTY_POP_PAGES_HIGH);
|
|
}
|
|
|
|
for (slot = pcpu_size_to_slot(PAGE_SIZE); slot < pcpu_nr_slots; slot++) {
|
|
int nr_unpop = 0, rs, re;
|
|
|
|
if (!nr_to_pop)
|
|
break;
|
|
|
|
spin_lock_irq(&pcpu_lock);
|
|
list_for_each_entry(chunk, &pcpu_slot[slot], list) {
|
|
nr_unpop = pcpu_unit_pages - chunk->nr_populated;
|
|
if (nr_unpop)
|
|
break;
|
|
}
|
|
spin_unlock_irq(&pcpu_lock);
|
|
|
|
if (!nr_unpop)
|
|
continue;
|
|
|
|
/* @chunk can't go away while pcpu_alloc_mutex is held */
|
|
pcpu_for_each_unpop_region(chunk, rs, re, 0, pcpu_unit_pages) {
|
|
int nr = min(re - rs, nr_to_pop);
|
|
|
|
ret = pcpu_populate_chunk(chunk, rs, rs + nr);
|
|
if (!ret) {
|
|
nr_to_pop -= nr;
|
|
spin_lock_irq(&pcpu_lock);
|
|
pcpu_chunk_populated(chunk, rs, rs + nr);
|
|
spin_unlock_irq(&pcpu_lock);
|
|
} else {
|
|
nr_to_pop = 0;
|
|
}
|
|
|
|
if (!nr_to_pop)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (nr_to_pop) {
|
|
/* ran out of chunks to populate, create a new one and retry */
|
|
chunk = pcpu_create_chunk();
|
|
if (chunk) {
|
|
spin_lock_irq(&pcpu_lock);
|
|
pcpu_chunk_relocate(chunk, -1);
|
|
spin_unlock_irq(&pcpu_lock);
|
|
goto retry_pop;
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
}
|
|
|
|
/**
|
|
* free_percpu - free percpu area
|
|
* @ptr: pointer to area to free
|
|
*
|
|
* Free percpu area @ptr.
|
|
*
|
|
* CONTEXT:
|
|
* Can be called from atomic context.
|
|
*/
|
|
void free_percpu(void __percpu *ptr)
|
|
{
|
|
void *addr;
|
|
struct pcpu_chunk *chunk;
|
|
unsigned long flags;
|
|
int off, occ_pages;
|
|
|
|
if (!ptr)
|
|
return;
|
|
|
|
kmemleak_free_percpu(ptr);
|
|
|
|
addr = __pcpu_ptr_to_addr(ptr);
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
|
|
chunk = pcpu_chunk_addr_search(addr);
|
|
off = addr - chunk->base_addr;
|
|
|
|
pcpu_free_area(chunk, off, &occ_pages);
|
|
|
|
if (chunk != pcpu_reserved_chunk)
|
|
pcpu_nr_empty_pop_pages += occ_pages;
|
|
|
|
/* if there are more than one fully free chunks, wake up grim reaper */
|
|
if (chunk->free_size == pcpu_unit_size) {
|
|
struct pcpu_chunk *pos;
|
|
|
|
list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
|
|
if (pos != chunk) {
|
|
pcpu_schedule_balance_work();
|
|
break;
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(free_percpu);
|
|
|
|
/**
|
|
* is_kernel_percpu_address - test whether address is from static percpu area
|
|
* @addr: address to test
|
|
*
|
|
* Test whether @addr belongs to in-kernel static percpu area. Module
|
|
* static percpu areas are not considered. For those, use
|
|
* is_module_percpu_address().
|
|
*
|
|
* RETURNS:
|
|
* %true if @addr is from in-kernel static percpu area, %false otherwise.
|
|
*/
|
|
bool is_kernel_percpu_address(unsigned long addr)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
const size_t static_size = __per_cpu_end - __per_cpu_start;
|
|
void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
|
|
unsigned int cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
void *start = per_cpu_ptr(base, cpu);
|
|
|
|
if ((void *)addr >= start && (void *)addr < start + static_size)
|
|
return true;
|
|
}
|
|
#endif
|
|
/* on UP, can't distinguish from other static vars, always false */
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* per_cpu_ptr_to_phys - convert translated percpu address to physical address
|
|
* @addr: the address to be converted to physical address
|
|
*
|
|
* Given @addr which is dereferenceable address obtained via one of
|
|
* percpu access macros, this function translates it into its physical
|
|
* address. The caller is responsible for ensuring @addr stays valid
|
|
* until this function finishes.
|
|
*
|
|
* percpu allocator has special setup for the first chunk, which currently
|
|
* supports either embedding in linear address space or vmalloc mapping,
|
|
* and, from the second one, the backing allocator (currently either vm or
|
|
* km) provides translation.
|
|
*
|
|
* The addr can be translated simply without checking if it falls into the
|
|
* first chunk. But the current code reflects better how percpu allocator
|
|
* actually works, and the verification can discover both bugs in percpu
|
|
* allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
|
|
* code.
|
|
*
|
|
* RETURNS:
|
|
* The physical address for @addr.
|
|
*/
|
|
phys_addr_t per_cpu_ptr_to_phys(void *addr)
|
|
{
|
|
void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
|
|
bool in_first_chunk = false;
|
|
unsigned long first_low, first_high;
|
|
unsigned int cpu;
|
|
|
|
/*
|
|
* The following test on unit_low/high isn't strictly
|
|
* necessary but will speed up lookups of addresses which
|
|
* aren't in the first chunk.
|
|
*/
|
|
first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0);
|
|
first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu,
|
|
pcpu_unit_pages);
|
|
if ((unsigned long)addr >= first_low &&
|
|
(unsigned long)addr < first_high) {
|
|
for_each_possible_cpu(cpu) {
|
|
void *start = per_cpu_ptr(base, cpu);
|
|
|
|
if (addr >= start && addr < start + pcpu_unit_size) {
|
|
in_first_chunk = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (in_first_chunk) {
|
|
if (!is_vmalloc_addr(addr))
|
|
return __pa(addr);
|
|
else
|
|
return page_to_phys(vmalloc_to_page(addr)) +
|
|
offset_in_page(addr);
|
|
} else
|
|
return page_to_phys(pcpu_addr_to_page(addr)) +
|
|
offset_in_page(addr);
|
|
}
|
|
|
|
/**
|
|
* pcpu_alloc_alloc_info - allocate percpu allocation info
|
|
* @nr_groups: the number of groups
|
|
* @nr_units: the number of units
|
|
*
|
|
* Allocate ai which is large enough for @nr_groups groups containing
|
|
* @nr_units units. The returned ai's groups[0].cpu_map points to the
|
|
* cpu_map array which is long enough for @nr_units and filled with
|
|
* NR_CPUS. It's the caller's responsibility to initialize cpu_map
|
|
* pointer of other groups.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to the allocated pcpu_alloc_info on success, NULL on
|
|
* failure.
|
|
*/
|
|
struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
|
|
int nr_units)
|
|
{
|
|
struct pcpu_alloc_info *ai;
|
|
size_t base_size, ai_size;
|
|
void *ptr;
|
|
int unit;
|
|
|
|
base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
|
|
__alignof__(ai->groups[0].cpu_map[0]));
|
|
ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
|
|
|
|
ptr = memblock_virt_alloc_nopanic(PFN_ALIGN(ai_size), 0);
|
|
if (!ptr)
|
|
return NULL;
|
|
ai = ptr;
|
|
ptr += base_size;
|
|
|
|
ai->groups[0].cpu_map = ptr;
|
|
|
|
for (unit = 0; unit < nr_units; unit++)
|
|
ai->groups[0].cpu_map[unit] = NR_CPUS;
|
|
|
|
ai->nr_groups = nr_groups;
|
|
ai->__ai_size = PFN_ALIGN(ai_size);
|
|
|
|
return ai;
|
|
}
|
|
|
|
/**
|
|
* pcpu_free_alloc_info - free percpu allocation info
|
|
* @ai: pcpu_alloc_info to free
|
|
*
|
|
* Free @ai which was allocated by pcpu_alloc_alloc_info().
|
|
*/
|
|
void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
|
|
{
|
|
memblock_free_early(__pa(ai), ai->__ai_size);
|
|
}
|
|
|
|
/**
|
|
* pcpu_dump_alloc_info - print out information about pcpu_alloc_info
|
|
* @lvl: loglevel
|
|
* @ai: allocation info to dump
|
|
*
|
|
* Print out information about @ai using loglevel @lvl.
|
|
*/
|
|
static void pcpu_dump_alloc_info(const char *lvl,
|
|
const struct pcpu_alloc_info *ai)
|
|
{
|
|
int group_width = 1, cpu_width = 1, width;
|
|
char empty_str[] = "--------";
|
|
int alloc = 0, alloc_end = 0;
|
|
int group, v;
|
|
int upa, apl; /* units per alloc, allocs per line */
|
|
|
|
v = ai->nr_groups;
|
|
while (v /= 10)
|
|
group_width++;
|
|
|
|
v = num_possible_cpus();
|
|
while (v /= 10)
|
|
cpu_width++;
|
|
empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
|
|
|
|
upa = ai->alloc_size / ai->unit_size;
|
|
width = upa * (cpu_width + 1) + group_width + 3;
|
|
apl = rounddown_pow_of_two(max(60 / width, 1));
|
|
|
|
printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
|
|
lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
|
|
ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
|
|
|
|
for (group = 0; group < ai->nr_groups; group++) {
|
|
const struct pcpu_group_info *gi = &ai->groups[group];
|
|
int unit = 0, unit_end = 0;
|
|
|
|
BUG_ON(gi->nr_units % upa);
|
|
for (alloc_end += gi->nr_units / upa;
|
|
alloc < alloc_end; alloc++) {
|
|
if (!(alloc % apl)) {
|
|
printk(KERN_CONT "\n");
|
|
printk("%spcpu-alloc: ", lvl);
|
|
}
|
|
printk(KERN_CONT "[%0*d] ", group_width, group);
|
|
|
|
for (unit_end += upa; unit < unit_end; unit++)
|
|
if (gi->cpu_map[unit] != NR_CPUS)
|
|
printk(KERN_CONT "%0*d ", cpu_width,
|
|
gi->cpu_map[unit]);
|
|
else
|
|
printk(KERN_CONT "%s ", empty_str);
|
|
}
|
|
}
|
|
printk(KERN_CONT "\n");
|
|
}
|
|
|
|
/**
|
|
* pcpu_setup_first_chunk - initialize the first percpu chunk
|
|
* @ai: pcpu_alloc_info describing how to percpu area is shaped
|
|
* @base_addr: mapped address
|
|
*
|
|
* Initialize the first percpu chunk which contains the kernel static
|
|
* perpcu area. This function is to be called from arch percpu area
|
|
* setup path.
|
|
*
|
|
* @ai contains all information necessary to initialize the first
|
|
* chunk and prime the dynamic percpu allocator.
|
|
*
|
|
* @ai->static_size is the size of static percpu area.
|
|
*
|
|
* @ai->reserved_size, if non-zero, specifies the amount of bytes to
|
|
* reserve after the static area in the first chunk. This reserves
|
|
* the first chunk such that it's available only through reserved
|
|
* percpu allocation. This is primarily used to serve module percpu
|
|
* static areas on architectures where the addressing model has
|
|
* limited offset range for symbol relocations to guarantee module
|
|
* percpu symbols fall inside the relocatable range.
|
|
*
|
|
* @ai->dyn_size determines the number of bytes available for dynamic
|
|
* allocation in the first chunk. The area between @ai->static_size +
|
|
* @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
|
|
*
|
|
* @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
|
|
* and equal to or larger than @ai->static_size + @ai->reserved_size +
|
|
* @ai->dyn_size.
|
|
*
|
|
* @ai->atom_size is the allocation atom size and used as alignment
|
|
* for vm areas.
|
|
*
|
|
* @ai->alloc_size is the allocation size and always multiple of
|
|
* @ai->atom_size. This is larger than @ai->atom_size if
|
|
* @ai->unit_size is larger than @ai->atom_size.
|
|
*
|
|
* @ai->nr_groups and @ai->groups describe virtual memory layout of
|
|
* percpu areas. Units which should be colocated are put into the
|
|
* same group. Dynamic VM areas will be allocated according to these
|
|
* groupings. If @ai->nr_groups is zero, a single group containing
|
|
* all units is assumed.
|
|
*
|
|
* The caller should have mapped the first chunk at @base_addr and
|
|
* copied static data to each unit.
|
|
*
|
|
* If the first chunk ends up with both reserved and dynamic areas, it
|
|
* is served by two chunks - one to serve the core static and reserved
|
|
* areas and the other for the dynamic area. They share the same vm
|
|
* and page map but uses different area allocation map to stay away
|
|
* from each other. The latter chunk is circulated in the chunk slots
|
|
* and available for dynamic allocation like any other chunks.
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
|
|
void *base_addr)
|
|
{
|
|
static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
|
|
static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
|
|
size_t dyn_size = ai->dyn_size;
|
|
size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
|
|
struct pcpu_chunk *schunk, *dchunk = NULL;
|
|
unsigned long *group_offsets;
|
|
size_t *group_sizes;
|
|
unsigned long *unit_off;
|
|
unsigned int cpu;
|
|
int *unit_map;
|
|
int group, unit, i;
|
|
|
|
#define PCPU_SETUP_BUG_ON(cond) do { \
|
|
if (unlikely(cond)) { \
|
|
pr_emerg("PERCPU: failed to initialize, %s", #cond); \
|
|
pr_emerg("PERCPU: cpu_possible_mask=%*pb\n", \
|
|
cpumask_pr_args(cpu_possible_mask)); \
|
|
pcpu_dump_alloc_info(KERN_EMERG, ai); \
|
|
BUG(); \
|
|
} \
|
|
} while (0)
|
|
|
|
/* sanity checks */
|
|
PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
|
|
#ifdef CONFIG_SMP
|
|
PCPU_SETUP_BUG_ON(!ai->static_size);
|
|
PCPU_SETUP_BUG_ON(offset_in_page(__per_cpu_start));
|
|
#endif
|
|
PCPU_SETUP_BUG_ON(!base_addr);
|
|
PCPU_SETUP_BUG_ON(offset_in_page(base_addr));
|
|
PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
|
|
PCPU_SETUP_BUG_ON(offset_in_page(ai->unit_size));
|
|
PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
|
|
PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
|
|
PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
|
|
|
|
/* process group information and build config tables accordingly */
|
|
group_offsets = memblock_virt_alloc(ai->nr_groups *
|
|
sizeof(group_offsets[0]), 0);
|
|
group_sizes = memblock_virt_alloc(ai->nr_groups *
|
|
sizeof(group_sizes[0]), 0);
|
|
unit_map = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_map[0]), 0);
|
|
unit_off = memblock_virt_alloc(nr_cpu_ids * sizeof(unit_off[0]), 0);
|
|
|
|
for (cpu = 0; cpu < nr_cpu_ids; cpu++)
|
|
unit_map[cpu] = UINT_MAX;
|
|
|
|
pcpu_low_unit_cpu = NR_CPUS;
|
|
pcpu_high_unit_cpu = NR_CPUS;
|
|
|
|
for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
|
|
const struct pcpu_group_info *gi = &ai->groups[group];
|
|
|
|
group_offsets[group] = gi->base_offset;
|
|
group_sizes[group] = gi->nr_units * ai->unit_size;
|
|
|
|
for (i = 0; i < gi->nr_units; i++) {
|
|
cpu = gi->cpu_map[i];
|
|
if (cpu == NR_CPUS)
|
|
continue;
|
|
|
|
PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids);
|
|
PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
|
|
PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
|
|
|
|
unit_map[cpu] = unit + i;
|
|
unit_off[cpu] = gi->base_offset + i * ai->unit_size;
|
|
|
|
/* determine low/high unit_cpu */
|
|
if (pcpu_low_unit_cpu == NR_CPUS ||
|
|
unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
|
|
pcpu_low_unit_cpu = cpu;
|
|
if (pcpu_high_unit_cpu == NR_CPUS ||
|
|
unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
|
|
pcpu_high_unit_cpu = cpu;
|
|
}
|
|
}
|
|
pcpu_nr_units = unit;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
|
|
|
|
/* we're done parsing the input, undefine BUG macro and dump config */
|
|
#undef PCPU_SETUP_BUG_ON
|
|
pcpu_dump_alloc_info(KERN_DEBUG, ai);
|
|
|
|
pcpu_nr_groups = ai->nr_groups;
|
|
pcpu_group_offsets = group_offsets;
|
|
pcpu_group_sizes = group_sizes;
|
|
pcpu_unit_map = unit_map;
|
|
pcpu_unit_offsets = unit_off;
|
|
|
|
/* determine basic parameters */
|
|
pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
|
|
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
|
|
pcpu_atom_size = ai->atom_size;
|
|
pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
|
|
BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
|
|
|
|
/*
|
|
* Allocate chunk slots. The additional last slot is for
|
|
* empty chunks.
|
|
*/
|
|
pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
|
|
pcpu_slot = memblock_virt_alloc(
|
|
pcpu_nr_slots * sizeof(pcpu_slot[0]), 0);
|
|
for (i = 0; i < pcpu_nr_slots; i++)
|
|
INIT_LIST_HEAD(&pcpu_slot[i]);
|
|
|
|
/*
|
|
* Initialize static chunk. If reserved_size is zero, the
|
|
* static chunk covers static area + dynamic allocation area
|
|
* in the first chunk. If reserved_size is not zero, it
|
|
* covers static area + reserved area (mostly used for module
|
|
* static percpu allocation).
|
|
*/
|
|
schunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
|
|
INIT_LIST_HEAD(&schunk->list);
|
|
INIT_WORK(&schunk->map_extend_work, pcpu_map_extend_workfn);
|
|
schunk->base_addr = base_addr;
|
|
schunk->map = smap;
|
|
schunk->map_alloc = ARRAY_SIZE(smap);
|
|
schunk->immutable = true;
|
|
bitmap_fill(schunk->populated, pcpu_unit_pages);
|
|
schunk->nr_populated = pcpu_unit_pages;
|
|
|
|
if (ai->reserved_size) {
|
|
schunk->free_size = ai->reserved_size;
|
|
pcpu_reserved_chunk = schunk;
|
|
pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
|
|
} else {
|
|
schunk->free_size = dyn_size;
|
|
dyn_size = 0; /* dynamic area covered */
|
|
}
|
|
schunk->contig_hint = schunk->free_size;
|
|
|
|
schunk->map[0] = 1;
|
|
schunk->map[1] = ai->static_size;
|
|
schunk->map_used = 1;
|
|
if (schunk->free_size)
|
|
schunk->map[++schunk->map_used] = ai->static_size + schunk->free_size;
|
|
schunk->map[schunk->map_used] |= 1;
|
|
|
|
/* init dynamic chunk if necessary */
|
|
if (dyn_size) {
|
|
dchunk = memblock_virt_alloc(pcpu_chunk_struct_size, 0);
|
|
INIT_LIST_HEAD(&dchunk->list);
|
|
INIT_WORK(&dchunk->map_extend_work, pcpu_map_extend_workfn);
|
|
dchunk->base_addr = base_addr;
|
|
dchunk->map = dmap;
|
|
dchunk->map_alloc = ARRAY_SIZE(dmap);
|
|
dchunk->immutable = true;
|
|
bitmap_fill(dchunk->populated, pcpu_unit_pages);
|
|
dchunk->nr_populated = pcpu_unit_pages;
|
|
|
|
dchunk->contig_hint = dchunk->free_size = dyn_size;
|
|
dchunk->map[0] = 1;
|
|
dchunk->map[1] = pcpu_reserved_chunk_limit;
|
|
dchunk->map[2] = (pcpu_reserved_chunk_limit + dchunk->free_size) | 1;
|
|
dchunk->map_used = 2;
|
|
}
|
|
|
|
/* link the first chunk in */
|
|
pcpu_first_chunk = dchunk ?: schunk;
|
|
pcpu_nr_empty_pop_pages +=
|
|
pcpu_count_occupied_pages(pcpu_first_chunk, 1);
|
|
pcpu_chunk_relocate(pcpu_first_chunk, -1);
|
|
|
|
/* we're done */
|
|
pcpu_base_addr = base_addr;
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
|
|
[PCPU_FC_AUTO] = "auto",
|
|
[PCPU_FC_EMBED] = "embed",
|
|
[PCPU_FC_PAGE] = "page",
|
|
};
|
|
|
|
enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
|
|
|
|
static int __init percpu_alloc_setup(char *str)
|
|
{
|
|
if (!str)
|
|
return -EINVAL;
|
|
|
|
if (0)
|
|
/* nada */;
|
|
#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
|
|
else if (!strcmp(str, "embed"))
|
|
pcpu_chosen_fc = PCPU_FC_EMBED;
|
|
#endif
|
|
#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
|
|
else if (!strcmp(str, "page"))
|
|
pcpu_chosen_fc = PCPU_FC_PAGE;
|
|
#endif
|
|
else
|
|
pr_warning("PERCPU: unknown allocator %s specified\n", str);
|
|
|
|
return 0;
|
|
}
|
|
early_param("percpu_alloc", percpu_alloc_setup);
|
|
|
|
/*
|
|
* pcpu_embed_first_chunk() is used by the generic percpu setup.
|
|
* Build it if needed by the arch config or the generic setup is going
|
|
* to be used.
|
|
*/
|
|
#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
|
|
!defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
|
|
#define BUILD_EMBED_FIRST_CHUNK
|
|
#endif
|
|
|
|
/* build pcpu_page_first_chunk() iff needed by the arch config */
|
|
#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
|
|
#define BUILD_PAGE_FIRST_CHUNK
|
|
#endif
|
|
|
|
/* pcpu_build_alloc_info() is used by both embed and page first chunk */
|
|
#if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
|
|
/**
|
|
* pcpu_build_alloc_info - build alloc_info considering distances between CPUs
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @dyn_size: minimum free size for dynamic allocation in bytes
|
|
* @atom_size: allocation atom size
|
|
* @cpu_distance_fn: callback to determine distance between cpus, optional
|
|
*
|
|
* This function determines grouping of units, their mappings to cpus
|
|
* and other parameters considering needed percpu size, allocation
|
|
* atom size and distances between CPUs.
|
|
*
|
|
* Groups are always multiples of atom size and CPUs which are of
|
|
* LOCAL_DISTANCE both ways are grouped together and share space for
|
|
* units in the same group. The returned configuration is guaranteed
|
|
* to have CPUs on different nodes on different groups and >=75% usage
|
|
* of allocated virtual address space.
|
|
*
|
|
* RETURNS:
|
|
* On success, pointer to the new allocation_info is returned. On
|
|
* failure, ERR_PTR value is returned.
|
|
*/
|
|
static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
|
|
size_t reserved_size, size_t dyn_size,
|
|
size_t atom_size,
|
|
pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
|
|
{
|
|
static int group_map[NR_CPUS] __initdata;
|
|
static int group_cnt[NR_CPUS] __initdata;
|
|
const size_t static_size = __per_cpu_end - __per_cpu_start;
|
|
int nr_groups = 1, nr_units = 0;
|
|
size_t size_sum, min_unit_size, alloc_size;
|
|
int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */
|
|
int last_allocs, group, unit;
|
|
unsigned int cpu, tcpu;
|
|
struct pcpu_alloc_info *ai;
|
|
unsigned int *cpu_map;
|
|
|
|
/* this function may be called multiple times */
|
|
memset(group_map, 0, sizeof(group_map));
|
|
memset(group_cnt, 0, sizeof(group_cnt));
|
|
|
|
/* calculate size_sum and ensure dyn_size is enough for early alloc */
|
|
size_sum = PFN_ALIGN(static_size + reserved_size +
|
|
max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
|
|
dyn_size = size_sum - static_size - reserved_size;
|
|
|
|
/*
|
|
* Determine min_unit_size, alloc_size and max_upa such that
|
|
* alloc_size is multiple of atom_size and is the smallest
|
|
* which can accommodate 4k aligned segments which are equal to
|
|
* or larger than min_unit_size.
|
|
*/
|
|
min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
|
|
|
|
alloc_size = roundup(min_unit_size, atom_size);
|
|
upa = alloc_size / min_unit_size;
|
|
while (alloc_size % upa || (offset_in_page(alloc_size / upa)))
|
|
upa--;
|
|
max_upa = upa;
|
|
|
|
/* group cpus according to their proximity */
|
|
for_each_possible_cpu(cpu) {
|
|
group = 0;
|
|
next_group:
|
|
for_each_possible_cpu(tcpu) {
|
|
if (cpu == tcpu)
|
|
break;
|
|
if (group_map[tcpu] == group && cpu_distance_fn &&
|
|
(cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
|
|
cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
|
|
group++;
|
|
nr_groups = max(nr_groups, group + 1);
|
|
goto next_group;
|
|
}
|
|
}
|
|
group_map[cpu] = group;
|
|
group_cnt[group]++;
|
|
}
|
|
|
|
/*
|
|
* Expand unit size until address space usage goes over 75%
|
|
* and then as much as possible without using more address
|
|
* space.
|
|
*/
|
|
last_allocs = INT_MAX;
|
|
for (upa = max_upa; upa; upa--) {
|
|
int allocs = 0, wasted = 0;
|
|
|
|
if (alloc_size % upa || (offset_in_page(alloc_size / upa)))
|
|
continue;
|
|
|
|
for (group = 0; group < nr_groups; group++) {
|
|
int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
|
|
allocs += this_allocs;
|
|
wasted += this_allocs * upa - group_cnt[group];
|
|
}
|
|
|
|
/*
|
|
* Don't accept if wastage is over 1/3. The
|
|
* greater-than comparison ensures upa==1 always
|
|
* passes the following check.
|
|
*/
|
|
if (wasted > num_possible_cpus() / 3)
|
|
continue;
|
|
|
|
/* and then don't consume more memory */
|
|
if (allocs > last_allocs)
|
|
break;
|
|
last_allocs = allocs;
|
|
best_upa = upa;
|
|
}
|
|
upa = best_upa;
|
|
|
|
/* allocate and fill alloc_info */
|
|
for (group = 0; group < nr_groups; group++)
|
|
nr_units += roundup(group_cnt[group], upa);
|
|
|
|
ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
|
|
if (!ai)
|
|
return ERR_PTR(-ENOMEM);
|
|
cpu_map = ai->groups[0].cpu_map;
|
|
|
|
for (group = 0; group < nr_groups; group++) {
|
|
ai->groups[group].cpu_map = cpu_map;
|
|
cpu_map += roundup(group_cnt[group], upa);
|
|
}
|
|
|
|
ai->static_size = static_size;
|
|
ai->reserved_size = reserved_size;
|
|
ai->dyn_size = dyn_size;
|
|
ai->unit_size = alloc_size / upa;
|
|
ai->atom_size = atom_size;
|
|
ai->alloc_size = alloc_size;
|
|
|
|
for (group = 0, unit = 0; group_cnt[group]; group++) {
|
|
struct pcpu_group_info *gi = &ai->groups[group];
|
|
|
|
/*
|
|
* Initialize base_offset as if all groups are located
|
|
* back-to-back. The caller should update this to
|
|
* reflect actual allocation.
|
|
*/
|
|
gi->base_offset = unit * ai->unit_size;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
if (group_map[cpu] == group)
|
|
gi->cpu_map[gi->nr_units++] = cpu;
|
|
gi->nr_units = roundup(gi->nr_units, upa);
|
|
unit += gi->nr_units;
|
|
}
|
|
BUG_ON(unit != nr_units);
|
|
|
|
return ai;
|
|
}
|
|
#endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
|
|
|
|
#if defined(BUILD_EMBED_FIRST_CHUNK)
|
|
/**
|
|
* pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @dyn_size: minimum free size for dynamic allocation in bytes
|
|
* @atom_size: allocation atom size
|
|
* @cpu_distance_fn: callback to determine distance between cpus, optional
|
|
* @alloc_fn: function to allocate percpu page
|
|
* @free_fn: function to free percpu page
|
|
*
|
|
* This is a helper to ease setting up embedded first percpu chunk and
|
|
* can be called where pcpu_setup_first_chunk() is expected.
|
|
*
|
|
* If this function is used to setup the first chunk, it is allocated
|
|
* by calling @alloc_fn and used as-is without being mapped into
|
|
* vmalloc area. Allocations are always whole multiples of @atom_size
|
|
* aligned to @atom_size.
|
|
*
|
|
* This enables the first chunk to piggy back on the linear physical
|
|
* mapping which often uses larger page size. Please note that this
|
|
* can result in very sparse cpu->unit mapping on NUMA machines thus
|
|
* requiring large vmalloc address space. Don't use this allocator if
|
|
* vmalloc space is not orders of magnitude larger than distances
|
|
* between node memory addresses (ie. 32bit NUMA machines).
|
|
*
|
|
* @dyn_size specifies the minimum dynamic area size.
|
|
*
|
|
* If the needed size is smaller than the minimum or specified unit
|
|
* size, the leftover is returned using @free_fn.
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
|
|
size_t atom_size,
|
|
pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
|
|
pcpu_fc_alloc_fn_t alloc_fn,
|
|
pcpu_fc_free_fn_t free_fn)
|
|
{
|
|
void *base = (void *)ULONG_MAX;
|
|
void **areas = NULL;
|
|
struct pcpu_alloc_info *ai;
|
|
size_t size_sum, areas_size, max_distance;
|
|
int group, i, rc;
|
|
|
|
ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
|
|
cpu_distance_fn);
|
|
if (IS_ERR(ai))
|
|
return PTR_ERR(ai);
|
|
|
|
size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
|
|
areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
|
|
|
|
areas = memblock_virt_alloc_nopanic(areas_size, 0);
|
|
if (!areas) {
|
|
rc = -ENOMEM;
|
|
goto out_free;
|
|
}
|
|
|
|
/* allocate, copy and determine base address */
|
|
for (group = 0; group < ai->nr_groups; group++) {
|
|
struct pcpu_group_info *gi = &ai->groups[group];
|
|
unsigned int cpu = NR_CPUS;
|
|
void *ptr;
|
|
|
|
for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
|
|
cpu = gi->cpu_map[i];
|
|
BUG_ON(cpu == NR_CPUS);
|
|
|
|
/* allocate space for the whole group */
|
|
ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
|
|
if (!ptr) {
|
|
rc = -ENOMEM;
|
|
goto out_free_areas;
|
|
}
|
|
/* kmemleak tracks the percpu allocations separately */
|
|
kmemleak_free(ptr);
|
|
areas[group] = ptr;
|
|
|
|
base = min(ptr, base);
|
|
}
|
|
|
|
/*
|
|
* Copy data and free unused parts. This should happen after all
|
|
* allocations are complete; otherwise, we may end up with
|
|
* overlapping groups.
|
|
*/
|
|
for (group = 0; group < ai->nr_groups; group++) {
|
|
struct pcpu_group_info *gi = &ai->groups[group];
|
|
void *ptr = areas[group];
|
|
|
|
for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
|
|
if (gi->cpu_map[i] == NR_CPUS) {
|
|
/* unused unit, free whole */
|
|
free_fn(ptr, ai->unit_size);
|
|
continue;
|
|
}
|
|
/* copy and return the unused part */
|
|
memcpy(ptr, __per_cpu_load, ai->static_size);
|
|
free_fn(ptr + size_sum, ai->unit_size - size_sum);
|
|
}
|
|
}
|
|
|
|
/* base address is now known, determine group base offsets */
|
|
max_distance = 0;
|
|
for (group = 0; group < ai->nr_groups; group++) {
|
|
ai->groups[group].base_offset = areas[group] - base;
|
|
max_distance = max_t(size_t, max_distance,
|
|
ai->groups[group].base_offset);
|
|
}
|
|
max_distance += ai->unit_size;
|
|
|
|
/* warn if maximum distance is further than 75% of vmalloc space */
|
|
if (max_distance > VMALLOC_TOTAL * 3 / 4) {
|
|
pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc "
|
|
"space 0x%lx\n", max_distance,
|
|
VMALLOC_TOTAL);
|
|
#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
|
|
/* and fail if we have fallback */
|
|
rc = -EINVAL;
|
|
goto out_free;
|
|
#endif
|
|
}
|
|
|
|
pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
|
|
PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
|
|
ai->dyn_size, ai->unit_size);
|
|
|
|
rc = pcpu_setup_first_chunk(ai, base);
|
|
goto out_free;
|
|
|
|
out_free_areas:
|
|
for (group = 0; group < ai->nr_groups; group++)
|
|
if (areas[group])
|
|
free_fn(areas[group],
|
|
ai->groups[group].nr_units * ai->unit_size);
|
|
out_free:
|
|
pcpu_free_alloc_info(ai);
|
|
if (areas)
|
|
memblock_free_early(__pa(areas), areas_size);
|
|
return rc;
|
|
}
|
|
#endif /* BUILD_EMBED_FIRST_CHUNK */
|
|
|
|
#ifdef BUILD_PAGE_FIRST_CHUNK
|
|
/**
|
|
* pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
|
|
* @free_fn: function to free percpu page, always called with PAGE_SIZE
|
|
* @populate_pte_fn: function to populate pte
|
|
*
|
|
* This is a helper to ease setting up page-remapped first percpu
|
|
* chunk and can be called where pcpu_setup_first_chunk() is expected.
|
|
*
|
|
* This is the basic allocator. Static percpu area is allocated
|
|
* page-by-page into vmalloc area.
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int __init pcpu_page_first_chunk(size_t reserved_size,
|
|
pcpu_fc_alloc_fn_t alloc_fn,
|
|
pcpu_fc_free_fn_t free_fn,
|
|
pcpu_fc_populate_pte_fn_t populate_pte_fn)
|
|
{
|
|
static struct vm_struct vm;
|
|
struct pcpu_alloc_info *ai;
|
|
char psize_str[16];
|
|
int unit_pages;
|
|
size_t pages_size;
|
|
struct page **pages;
|
|
int unit, i, j, rc;
|
|
|
|
snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
|
|
|
|
ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
|
|
if (IS_ERR(ai))
|
|
return PTR_ERR(ai);
|
|
BUG_ON(ai->nr_groups != 1);
|
|
BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
|
|
|
|
unit_pages = ai->unit_size >> PAGE_SHIFT;
|
|
|
|
/* unaligned allocations can't be freed, round up to page size */
|
|
pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
|
|
sizeof(pages[0]));
|
|
pages = memblock_virt_alloc(pages_size, 0);
|
|
|
|
/* allocate pages */
|
|
j = 0;
|
|
for (unit = 0; unit < num_possible_cpus(); unit++)
|
|
for (i = 0; i < unit_pages; i++) {
|
|
unsigned int cpu = ai->groups[0].cpu_map[unit];
|
|
void *ptr;
|
|
|
|
ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
|
|
if (!ptr) {
|
|
pr_warning("PERCPU: failed to allocate %s page "
|
|
"for cpu%u\n", psize_str, cpu);
|
|
goto enomem;
|
|
}
|
|
/* kmemleak tracks the percpu allocations separately */
|
|
kmemleak_free(ptr);
|
|
pages[j++] = virt_to_page(ptr);
|
|
}
|
|
|
|
/* allocate vm area, map the pages and copy static data */
|
|
vm.flags = VM_ALLOC;
|
|
vm.size = num_possible_cpus() * ai->unit_size;
|
|
vm_area_register_early(&vm, PAGE_SIZE);
|
|
|
|
for (unit = 0; unit < num_possible_cpus(); unit++) {
|
|
unsigned long unit_addr =
|
|
(unsigned long)vm.addr + unit * ai->unit_size;
|
|
|
|
for (i = 0; i < unit_pages; i++)
|
|
populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
|
|
|
|
/* pte already populated, the following shouldn't fail */
|
|
rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
|
|
unit_pages);
|
|
if (rc < 0)
|
|
panic("failed to map percpu area, err=%d\n", rc);
|
|
|
|
/*
|
|
* FIXME: Archs with virtual cache should flush local
|
|
* cache for the linear mapping here - something
|
|
* equivalent to flush_cache_vmap() on the local cpu.
|
|
* flush_cache_vmap() can't be used as most supporting
|
|
* data structures are not set up yet.
|
|
*/
|
|
|
|
/* copy static data */
|
|
memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
|
|
}
|
|
|
|
/* we're ready, commit */
|
|
pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
|
|
unit_pages, psize_str, vm.addr, ai->static_size,
|
|
ai->reserved_size, ai->dyn_size);
|
|
|
|
rc = pcpu_setup_first_chunk(ai, vm.addr);
|
|
goto out_free_ar;
|
|
|
|
enomem:
|
|
while (--j >= 0)
|
|
free_fn(page_address(pages[j]), PAGE_SIZE);
|
|
rc = -ENOMEM;
|
|
out_free_ar:
|
|
memblock_free_early(__pa(pages), pages_size);
|
|
pcpu_free_alloc_info(ai);
|
|
return rc;
|
|
}
|
|
#endif /* BUILD_PAGE_FIRST_CHUNK */
|
|
|
|
#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
|
|
/*
|
|
* Generic SMP percpu area setup.
|
|
*
|
|
* The embedding helper is used because its behavior closely resembles
|
|
* the original non-dynamic generic percpu area setup. This is
|
|
* important because many archs have addressing restrictions and might
|
|
* fail if the percpu area is located far away from the previous
|
|
* location. As an added bonus, in non-NUMA cases, embedding is
|
|
* generally a good idea TLB-wise because percpu area can piggy back
|
|
* on the physical linear memory mapping which uses large page
|
|
* mappings on applicable archs.
|
|
*/
|
|
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
|
|
EXPORT_SYMBOL(__per_cpu_offset);
|
|
|
|
static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
|
|
size_t align)
|
|
{
|
|
return memblock_virt_alloc_from_nopanic(
|
|
size, align, __pa(MAX_DMA_ADDRESS));
|
|
}
|
|
|
|
static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
|
|
{
|
|
memblock_free_early(__pa(ptr), size);
|
|
}
|
|
|
|
void __init setup_per_cpu_areas(void)
|
|
{
|
|
unsigned long delta;
|
|
unsigned int cpu;
|
|
int rc;
|
|
|
|
/*
|
|
* Always reserve area for module percpu variables. That's
|
|
* what the legacy allocator did.
|
|
*/
|
|
rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
|
|
PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
|
|
pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
|
|
if (rc < 0)
|
|
panic("Failed to initialize percpu areas.");
|
|
|
|
delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
|
|
for_each_possible_cpu(cpu)
|
|
__per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
|
|
}
|
|
#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
|
|
|
|
#else /* CONFIG_SMP */
|
|
|
|
/*
|
|
* UP percpu area setup.
|
|
*
|
|
* UP always uses km-based percpu allocator with identity mapping.
|
|
* Static percpu variables are indistinguishable from the usual static
|
|
* variables and don't require any special preparation.
|
|
*/
|
|
void __init setup_per_cpu_areas(void)
|
|
{
|
|
const size_t unit_size =
|
|
roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
|
|
PERCPU_DYNAMIC_RESERVE));
|
|
struct pcpu_alloc_info *ai;
|
|
void *fc;
|
|
|
|
ai = pcpu_alloc_alloc_info(1, 1);
|
|
fc = memblock_virt_alloc_from_nopanic(unit_size,
|
|
PAGE_SIZE,
|
|
__pa(MAX_DMA_ADDRESS));
|
|
if (!ai || !fc)
|
|
panic("Failed to allocate memory for percpu areas.");
|
|
/* kmemleak tracks the percpu allocations separately */
|
|
kmemleak_free(fc);
|
|
|
|
ai->dyn_size = unit_size;
|
|
ai->unit_size = unit_size;
|
|
ai->atom_size = unit_size;
|
|
ai->alloc_size = unit_size;
|
|
ai->groups[0].nr_units = 1;
|
|
ai->groups[0].cpu_map[0] = 0;
|
|
|
|
if (pcpu_setup_first_chunk(ai, fc) < 0)
|
|
panic("Failed to initialize percpu areas.");
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|
|
|
|
/*
|
|
* First and reserved chunks are initialized with temporary allocation
|
|
* map in initdata so that they can be used before slab is online.
|
|
* This function is called after slab is brought up and replaces those
|
|
* with properly allocated maps.
|
|
*/
|
|
void __init percpu_init_late(void)
|
|
{
|
|
struct pcpu_chunk *target_chunks[] =
|
|
{ pcpu_first_chunk, pcpu_reserved_chunk, NULL };
|
|
struct pcpu_chunk *chunk;
|
|
unsigned long flags;
|
|
int i;
|
|
|
|
for (i = 0; (chunk = target_chunks[i]); i++) {
|
|
int *map;
|
|
const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]);
|
|
|
|
BUILD_BUG_ON(size > PAGE_SIZE);
|
|
|
|
map = pcpu_mem_zalloc(size);
|
|
BUG_ON(!map);
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
memcpy(map, chunk->map, size);
|
|
chunk->map = map;
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Percpu allocator is initialized early during boot when neither slab or
|
|
* workqueue is available. Plug async management until everything is up
|
|
* and running.
|
|
*/
|
|
static int __init percpu_enable_async(void)
|
|
{
|
|
pcpu_async_enabled = true;
|
|
return 0;
|
|
}
|
|
subsys_initcall(percpu_enable_async);
|