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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235// SPDX-License-Identifier: GPL-2.0-only/* * * Copyright (C) 2017 Facebook Inc. * Copyright (C) 2017 Dennis Zhou <dennis@kernel.org> * * Prints statistics about the percpu allocator and backing chunks. */#include <linux/debugfs.h>#include <linux/list.h>#include <linux/percpu.h>#include <linux/seq_file.h>#include <linux/sort.h>#include <linux/vmalloc.h>
#include "percpu-internal.h"
#define P(X, Y) \ seq_printf(m, " %-20s: %12lld\n", X, (long long int)Y)
struct percpu_stats pcpu_stats;struct pcpu_alloc_info pcpu_stats_ai;
static int cmpint(const void *a, const void *b){ return *(int *)a - *(int *)b;}
/* * Iterates over all chunks to find the max nr_alloc entries. */static int find_max_nr_alloc(void){ struct pcpu_chunk *chunk; int slot, max_nr_alloc;
max_nr_alloc = 0; for (slot = 0; slot < pcpu_nr_slots; slot++) list_for_each_entry(chunk, &pcpu_chunk_lists[slot], list) max_nr_alloc = max(max_nr_alloc, chunk->nr_alloc);
return max_nr_alloc;}
/* * Prints out chunk state. Fragmentation is considered between * the beginning of the chunk to the last allocation. * * All statistics are in bytes unless stated otherwise. */static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk, int *buffer){ struct pcpu_block_md *chunk_md = &chunk->chunk_md; int i, last_alloc, as_len, start, end; int *alloc_sizes, *p; /* statistics */ int sum_frag = 0, max_frag = 0; int cur_min_alloc = 0, cur_med_alloc = 0, cur_max_alloc = 0;
alloc_sizes = buffer;
/* * find_last_bit returns the start value if nothing found. * Therefore, we must determine if it is a failure of find_last_bit * and set the appropriate value. */ last_alloc = find_last_bit(chunk->alloc_map, pcpu_chunk_map_bits(chunk) - chunk->end_offset / PCPU_MIN_ALLOC_SIZE - 1); last_alloc = test_bit(last_alloc, chunk->alloc_map) ? last_alloc + 1 : 0;
as_len = 0; start = chunk->start_offset / PCPU_MIN_ALLOC_SIZE;
/* * If a bit is set in the allocation map, the bound_map identifies * where the allocation ends. If the allocation is not set, the * bound_map does not identify free areas as it is only kept accurate * on allocation, not free. * * Positive values are allocations and negative values are free * fragments. */ while (start < last_alloc) { if (test_bit(start, chunk->alloc_map)) { end = find_next_bit(chunk->bound_map, last_alloc, start + 1); alloc_sizes[as_len] = 1; } else { end = find_next_bit(chunk->alloc_map, last_alloc, start + 1); alloc_sizes[as_len] = -1; }
alloc_sizes[as_len++] *= (end - start) * PCPU_MIN_ALLOC_SIZE;
start = end; }
/* * The negative values are free fragments and thus sorting gives the * free fragments at the beginning in largest first order. */ if (as_len > 0) { sort(alloc_sizes, as_len, sizeof(int), cmpint, NULL);
/* iterate through the unallocated fragments */ for (i = 0, p = alloc_sizes; *p < 0 && i < as_len; i++, p++) { sum_frag -= *p; max_frag = max(max_frag, -1 * (*p)); }
cur_min_alloc = alloc_sizes[i]; cur_med_alloc = alloc_sizes[(i + as_len - 1) / 2]; cur_max_alloc = alloc_sizes[as_len - 1]; }
P("nr_alloc", chunk->nr_alloc); P("max_alloc_size", chunk->max_alloc_size); P("empty_pop_pages", chunk->nr_empty_pop_pages); P("first_bit", chunk_md->first_free); P("free_bytes", chunk->free_bytes); P("contig_bytes", chunk_md->contig_hint * PCPU_MIN_ALLOC_SIZE); P("sum_frag", sum_frag); P("max_frag", max_frag); P("cur_min_alloc", cur_min_alloc); P("cur_med_alloc", cur_med_alloc); P("cur_max_alloc", cur_max_alloc); seq_putc(m, '\n');}
static int percpu_stats_show(struct seq_file *m, void *v){ struct pcpu_chunk *chunk; int slot, max_nr_alloc; int *buffer;
alloc_buffer: spin_lock_irq(&pcpu_lock); max_nr_alloc = find_max_nr_alloc(); spin_unlock_irq(&pcpu_lock);
/* there can be at most this many free and allocated fragments */ buffer = vmalloc_array(2 * max_nr_alloc + 1, sizeof(int)); if (!buffer) return -ENOMEM;
spin_lock_irq(&pcpu_lock);
/* if the buffer allocated earlier is too small */ if (max_nr_alloc < find_max_nr_alloc()) { spin_unlock_irq(&pcpu_lock); vfree(buffer); goto alloc_buffer; }
#define PL(X) \ seq_printf(m, " %-20s: %12lld\n", #X, (long long int)pcpu_stats_ai.X)
seq_printf(m, "Percpu Memory Statistics\n" "Allocation Info:\n" "----------------------------------------\n"); PL(unit_size); PL(static_size); PL(reserved_size); PL(dyn_size); PL(atom_size); PL(alloc_size); seq_putc(m, '\n');
#undef PL
#define PU(X) \ seq_printf(m, " %-20s: %12llu\n", #X, (unsigned long long)pcpu_stats.X)
seq_printf(m, "Global Stats:\n" "----------------------------------------\n"); PU(nr_alloc); PU(nr_dealloc); PU(nr_cur_alloc); PU(nr_max_alloc); PU(nr_chunks); PU(nr_max_chunks); PU(min_alloc_size); PU(max_alloc_size); P("empty_pop_pages", pcpu_nr_empty_pop_pages); seq_putc(m, '\n');
#undef PU
seq_printf(m, "Per Chunk Stats:\n" "----------------------------------------\n");
if (pcpu_reserved_chunk) { seq_puts(m, "Chunk: <- Reserved Chunk\n"); chunk_map_stats(m, pcpu_reserved_chunk, buffer); }
for (slot = 0; slot < pcpu_nr_slots; slot++) { list_for_each_entry(chunk, &pcpu_chunk_lists[slot], list) { if (chunk == pcpu_first_chunk) seq_puts(m, "Chunk: <- First Chunk\n"); else if (slot == pcpu_to_depopulate_slot) seq_puts(m, "Chunk (to_depopulate)\n"); else if (slot == pcpu_sidelined_slot) seq_puts(m, "Chunk (sidelined):\n"); else seq_puts(m, "Chunk:\n"); chunk_map_stats(m, chunk, buffer); } }
spin_unlock_irq(&pcpu_lock);
vfree(buffer);
return 0;}DEFINE_SHOW_ATTRIBUTE(percpu_stats);
static int __init init_percpu_stats_debugfs(void){ debugfs_create_file("percpu_stats", 0444, NULL, NULL, &percpu_stats_fops);
return 0;}
late_initcall(init_percpu_stats_debugfs);