diff options
| -rw-r--r-- | mm/migrate.c | 179 |
1 files changed, 174 insertions, 5 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 676d9cfc7059ca..ae993b71ef9abf 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -44,6 +44,7 @@ #include <linux/sched/sysctl.h> #include <linux/memory-tiers.h> #include <linux/pagewalk.h> +#include <linux/debugfs.h> #include <asm/tlbflush.h> @@ -791,6 +792,125 @@ int migrate_folio(struct address_space *mapping, struct folio *dst, EXPORT_SYMBOL(migrate_folio); #ifdef CONFIG_BUFFER_HEAD + +static const char * const bh_routine_names[] = { + "buffer_migrate_folio", + "buffer_migrate_folio_norefs", +}; + +#define BH_STATS(X) \ + X(bh_migrate_folio, 0, "calls") \ + X(bh_migrate_folio_success, 0, "success") \ + X(bh_migrate_folio_fails, 0, "fails") \ + X(bh_migrate_folio_norefs, 1, "calls") \ + X(bh_migrate_folio_norefs_success, 1, "success") \ + X(bh_migrate_folio_norefs_fails, 1, "fails") \ + X(bh_migrate_folio_norefs_nohead_success, 1, "no-head-success") \ + X(bh_migrate_folio_norefs_nohead_fails, 1, "no-head-fails") \ + X(bh_migrate_folio_norefs_invalid, 1, "invalid") \ + X(bh_migrate_folio_norefs_valid, 1, "valid") \ + X(bh_migrate_folio_norefs_valid_success, 1, "valid-success") \ + X(bh_migrate_folio_norefs_valid_fails, 1, "valid-fails") + + +#define DECLARE_STAT(name, routine_idx, meaning) static atomic_long_t name; +BH_STATS(DECLARE_STAT) + +#define BH_STAT_PTR(name, routine_idx, meaning) &name, +static atomic_long_t * const bh_stat_array[] = { + BH_STATS(BH_STAT_PTR) +}; + +#define BH_STAT_ROUTINE_IDX(name, routine_idx, meaning) routine_idx, +static const int bh_stat_routine_index[] = { + BH_STATS(BH_STAT_ROUTINE_IDX) +}; + +#define BH_STAT_MEANING(name, routine_idx, meaning) meaning, +static const char * const bh_stat_meanings[] = { + BH_STATS(BH_STAT_MEANING) +}; + +#define NUM_BH_STATS ARRAY_SIZE(bh_stat_array) + +static ssize_t read_file_bh_migrate_stats(struct file *file, + char __user *user_buf, + size_t count, loff_t *ppos) +{ + char *buf; + unsigned int i, len = 0, size = NUM_BH_STATS * 128; + int ret, last_routine = -1; + unsigned long total, success, rate; + + BUILD_BUG_ON(ARRAY_SIZE(bh_stat_array) != ARRAY_SIZE(bh_stat_meanings)); + + buf = kzalloc(size, GFP_KERNEL); + if (buf == NULL) + return -ENOMEM; + + for (i = 0; i < NUM_BH_STATS; i++) { + int routine_idx = bh_stat_routine_index[i]; + + if (routine_idx != last_routine) { + len += scnprintf(buf + len, size - len, "\n[%s]\n", + bh_routine_names[routine_idx]); + last_routine = routine_idx; + } + + len += scnprintf(buf + len, size - len, "%25s\t%lu\n", + bh_stat_meanings[i], + atomic_long_read(bh_stat_array[i])); + + } + + len += scnprintf(buf + len, size - len, "\nSuccess ratios:\n"); + + total = atomic_long_read(&bh_migrate_folio); + success = atomic_long_read(&bh_migrate_folio_success); + rate = total ? (success * 100) / total : 0; + len += scnprintf(buf + len, size - len, + "%s: %lu%% success (%lu/%lu)\n", + "buffer_migrate_folio", rate, success, total); + + total = atomic_long_read(&bh_migrate_folio_norefs); + success = atomic_long_read(&bh_migrate_folio_norefs_success); + rate = total ? (success * 100) / total : 0; + len += scnprintf(buf + len, size - len, + "%s: %lu%% success (%lu/%lu)\n", + "buffer_migrate_folio_norefs", rate, success, total); + + ret = simple_read_from_buffer(user_buf, count, ppos, buf, len); + kfree(buf); + return ret; +} + +static const struct file_operations fops_bh_migrate_stats = { + .read = read_file_bh_migrate_stats, + .open = simple_open, + .owner = THIS_MODULE, + .llseek = default_llseek, +}; + +static void mm_migrate_bh_init(struct dentry *migrate_debug_root) +{ + struct dentry *parent_dirs[ARRAY_SIZE(bh_routine_names)] = { NULL }; + struct dentry *root = debugfs_create_dir("bh", migrate_debug_root); + int i; + + for (i = 0; i < ARRAY_SIZE(bh_routine_names); i++) + parent_dirs[i] = debugfs_create_dir(bh_routine_names[i], root); + + for (i = 0; i < NUM_BH_STATS; i++) { + int routine = bh_stat_routine_index[i]; + debugfs_create_ulong(bh_stat_meanings[i], 0400, + parent_dirs[routine], + (unsigned long *) + &bh_stat_array[i]->counter); + } + + debugfs_create_file("stats", 0400, root, root, &fops_bh_migrate_stats); +} + /* Returns true if all buffers are successfully locked */ static bool buffer_migrate_lock_buffers(struct buffer_head *head, enum migrate_mode mode) @@ -833,8 +953,16 @@ static int __buffer_migrate_folio(struct address_space *mapping, int expected_count; head = folio_buffers(src); - if (!head) - return migrate_folio(mapping, dst, src, mode); + if (!head) { + rc = migrate_folio(mapping, dst, src, mode); + if (check_refs) { + if (rc == 0) + atomic_long_inc(&bh_migrate_folio_norefs_nohead_success); + else + atomic_long_inc(&bh_migrate_folio_norefs_nohead_fails); + } + return rc; + } /* Check whether page does not have extra refs before we do more work */ expected_count = folio_expected_refs(mapping, src); @@ -865,17 +993,23 @@ recheck_buffers: if (busy) { if (invalidated) { rc = -EAGAIN; + atomic_long_inc(&bh_migrate_folio_norefs_invalid); goto unlock_buffers; } invalidate_bh_lrus(); invalidated = true; goto recheck_buffers; } + atomic_long_inc(&bh_migrate_folio_norefs_valid); } rc = filemap_migrate_folio(mapping, dst, src, mode); - if (rc != MIGRATEPAGE_SUCCESS) + if (rc != MIGRATEPAGE_SUCCESS) { + if (check_refs) + atomic_long_inc(&bh_migrate_folio_norefs_valid_fails); goto unlock_buffers; + } else if (check_refs) + atomic_long_inc(&bh_migrate_folio_norefs_valid_success); bh = head; do { @@ -913,7 +1047,16 @@ unlock_buffers: int buffer_migrate_folio(struct address_space *mapping, struct folio *dst, struct folio *src, enum migrate_mode mode) { - return __buffer_migrate_folio(mapping, dst, src, mode, false); + int ret; + atomic_long_inc(&bh_migrate_folio); + + ret = __buffer_migrate_folio(mapping, dst, src, mode, false); + if (ret == 0) + atomic_long_inc(&bh_migrate_folio_success); + else + atomic_long_inc(&bh_migrate_folio_fails); + + return ret; } EXPORT_SYMBOL(buffer_migrate_folio); @@ -934,9 +1077,21 @@ EXPORT_SYMBOL(buffer_migrate_folio); int buffer_migrate_folio_norefs(struct address_space *mapping, struct folio *dst, struct folio *src, enum migrate_mode mode) { - return __buffer_migrate_folio(mapping, dst, src, mode, true); + int ret; + + atomic_long_inc(&bh_migrate_folio_norefs); + + ret = __buffer_migrate_folio(mapping, dst, src, mode, true); + if (ret == 0) + atomic_long_inc(&bh_migrate_folio_norefs_success); + else + atomic_long_inc(&bh_migrate_folio_norefs_fails); + + return ret; } EXPORT_SYMBOL_GPL(buffer_migrate_folio_norefs); +#else +static inline void mm_migrate_bh_init(struct dentry *migrate_debug_root) { } #endif /* CONFIG_BUFFER_HEAD */ int filemap_migrate_folio(struct address_space *mapping, @@ -2735,3 +2890,17 @@ int migrate_misplaced_folio(struct folio *folio, int node) } #endif /* CONFIG_NUMA_BALANCING */ #endif /* CONFIG_NUMA */ + +static __init int mm_migrate_debugfs_init(void) +{ + struct dentry *mm_debug_root; + struct dentry *migrate_debug_root; + + mm_debug_root = debugfs_create_dir("mm", NULL); + migrate_debug_root = debugfs_create_dir("migrate", mm_debug_root); + + mm_migrate_bh_init(migrate_debug_root); + + return 0; +} +fs_initcall(mm_migrate_debugfs_init); |