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![Tejun Heo](/assets/img/avatar_default.png)
The percpu allocator now supports atomic allocations by only allocating from already populated areas but the mechanism to ensure that there's adequate amount of populated areas was missing. This patch expands pcpu_balance_work so that in addition to freeing excess free chunks it also populates chunks to maintain an adequate level of populated areas. pcpu_alloc() schedules pcpu_balance_work if the amount of free populated areas is too low or after an atomic allocation failure. * PERPCU_DYNAMIC_RESERVE is increased by two pages to account for PCPU_EMPTY_POP_PAGES_LOW. * pcpu_async_enabled is added to gate both async jobs - chunk->map_extend_work and pcpu_balance_work - so that we don't end up scheduling them while the needed subsystems aren't up yet. Signed-off-by: Tejun Heo <tj@kernel.org>
137 lines
4.2 KiB
C
137 lines
4.2 KiB
C
#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/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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#ifndef PERCPU_ENOUGH_ROOM
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#define PERCPU_ENOUGH_ROOM \
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(ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \
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PERCPU_MODULE_RESERVE)
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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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/*
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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);
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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 __init percpu_init_late(void);
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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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#endif /* __LINUX_PERCPU_H */
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