forked from mirrors/linux
b239f7daf5
Previously, block size was flexible based on the constraint that the GCD(PCPU_BITMAP_BLOCK_SIZE, PAGE_SIZE) > 1. However, this carried the overhead that keeping a floating number of populated free pages required scanning over the free regions of a chunk. Setting the block size to be fixed at PAGE_SIZE lets us know when an empty page becomes used as we will break a full contig_hint of a block. This means we no longer have to scan the whole chunk upon breaking a contig_hint which empty page management piggybacked off. A later patch takes advantage of this to optimize the allocation path by only scanning forward using the scan_hint introduced later too. Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: Peng Fan <peng.fan@nxp.com>
148 lines
4.6 KiB
C
148 lines
4.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_PERCPU_H
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#define __LINUX_PERCPU_H
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#include <linux/mmdebug.h>
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#include <linux/preempt.h>
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#include <linux/smp.h>
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#include <linux/cpumask.h>
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#include <linux/printk.h>
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#include <linux/pfn.h>
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#include <linux/init.h>
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#include <asm/percpu.h>
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/* enough to cover all DEFINE_PER_CPUs in modules */
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#ifdef CONFIG_MODULES
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#define PERCPU_MODULE_RESERVE (8 << 10)
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#else
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#define PERCPU_MODULE_RESERVE 0
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#endif
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/* minimum unit size, also is the maximum supported allocation size */
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#define PCPU_MIN_UNIT_SIZE PFN_ALIGN(32 << 10)
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/* minimum allocation size and shift in bytes */
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#define PCPU_MIN_ALLOC_SHIFT 2
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#define PCPU_MIN_ALLOC_SIZE (1 << PCPU_MIN_ALLOC_SHIFT)
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/*
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* The PCPU_BITMAP_BLOCK_SIZE must be the same size as PAGE_SIZE as the
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* updating of hints is used to manage the nr_empty_pop_pages in both
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* the chunk and globally.
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*/
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#define PCPU_BITMAP_BLOCK_SIZE PAGE_SIZE
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#define PCPU_BITMAP_BLOCK_BITS (PCPU_BITMAP_BLOCK_SIZE >> \
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PCPU_MIN_ALLOC_SHIFT)
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/*
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* Percpu allocator can serve percpu allocations before slab is
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* initialized which allows slab to depend on the percpu allocator.
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* The following two parameters decide how much resource to
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* preallocate for this. Keep PERCPU_DYNAMIC_RESERVE equal to or
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* larger than PERCPU_DYNAMIC_EARLY_SIZE.
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*/
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#define PERCPU_DYNAMIC_EARLY_SLOTS 128
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#define PERCPU_DYNAMIC_EARLY_SIZE (12 << 10)
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/*
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* PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
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* back on the first chunk for dynamic percpu allocation if arch is
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* manually allocating and mapping it for faster access (as a part of
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* large page mapping for example).
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*
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* The following values give between one and two pages of free space
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* after typical minimal boot (2-way SMP, single disk and NIC) with
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* both defconfig and a distro config on x86_64 and 32. More
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* intelligent way to determine this would be nice.
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*/
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#if BITS_PER_LONG > 32
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#define PERCPU_DYNAMIC_RESERVE (28 << 10)
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#else
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#define PERCPU_DYNAMIC_RESERVE (20 << 10)
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#endif
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extern void *pcpu_base_addr;
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extern const unsigned long *pcpu_unit_offsets;
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struct pcpu_group_info {
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int nr_units; /* aligned # of units */
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unsigned long base_offset; /* base address offset */
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unsigned int *cpu_map; /* unit->cpu map, empty
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* entries contain NR_CPUS */
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};
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struct pcpu_alloc_info {
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size_t static_size;
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size_t reserved_size;
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size_t dyn_size;
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size_t unit_size;
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size_t atom_size;
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size_t alloc_size;
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size_t __ai_size; /* internal, don't use */
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int nr_groups; /* 0 if grouping unnecessary */
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struct pcpu_group_info groups[];
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};
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enum pcpu_fc {
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PCPU_FC_AUTO,
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PCPU_FC_EMBED,
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PCPU_FC_PAGE,
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PCPU_FC_NR,
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};
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extern const char * const pcpu_fc_names[PCPU_FC_NR];
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extern enum pcpu_fc pcpu_chosen_fc;
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typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
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size_t align);
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typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
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typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
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typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
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extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
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int nr_units);
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extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
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extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
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void *base_addr);
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#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
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extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
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size_t atom_size,
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pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
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pcpu_fc_alloc_fn_t alloc_fn,
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pcpu_fc_free_fn_t free_fn);
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#endif
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#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
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extern int __init pcpu_page_first_chunk(size_t reserved_size,
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pcpu_fc_alloc_fn_t alloc_fn,
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pcpu_fc_free_fn_t free_fn,
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pcpu_fc_populate_pte_fn_t populate_pte_fn);
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#endif
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extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
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extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
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extern bool is_kernel_percpu_address(unsigned long addr);
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#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
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extern void __init setup_per_cpu_areas(void);
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#endif
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extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp);
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extern void __percpu *__alloc_percpu(size_t size, size_t align);
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extern void free_percpu(void __percpu *__pdata);
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extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
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#define alloc_percpu_gfp(type, gfp) \
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(typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type), \
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__alignof__(type), gfp)
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#define alloc_percpu(type) \
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(typeof(type) __percpu *)__alloc_percpu(sizeof(type), \
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__alignof__(type))
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extern unsigned long pcpu_nr_pages(void);
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#endif /* __LINUX_PERCPU_H */
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