alloc_calls and free_calls implementation in sysfs have two issues,
one is PAGE_SIZE limitiation of sysfs and other is it does not adhere
to "one value per file" rule.
To overcome this issues, move the alloc_calls and free_calls implemeation
to debugfs.
Signed-off-by: Faiyaz Mohammed <faiyazm@xxxxxxxxxxxxxx>
---
include/linux/slub_def.h | 10 +++
mm/slab_common.c | 9 +++
mm/slub.c | 202 ++++++++++++++++++++++++++++++++++++++++++-----
3 files changed, 200 insertions(+), 21 deletions(-)
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index dcde82a..f8c268d 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -110,6 +110,9 @@ struct kmem_cache {
#ifdef CONFIG_SYSFS
struct kobject kobj; /* For sysfs */
#endif
+#ifdef CONFIG_SLUB_DEBUG
+ struct dentry *slab_cache_dentry;
+#endif
#ifdef CONFIG_SLAB_FREELIST_HARDENED
unsigned long random;
#endif
@@ -159,6 +162,13 @@ static inline void sysfs_slab_release(struct kmem_cache *s)
}
#endif
+#ifdef CONFIG_DEBUG_FS
+void debugfs_slab_release(struct kmem_cache *);
+#else
+static inline void debugfs_slab_release(struct kmem_cache *s)
+{
+}
+#endif
void object_err(struct kmem_cache *s, struct page *page,
u8 *object, char *reason);
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 88e8339..fb28328 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -437,6 +437,9 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
#else
slab_kmem_cache_release(s);
#endif
+#ifdef CONFIG_DEBUG_FS
+ debugfs_slab_release(s);
+#endif
}
}
@@ -454,6 +457,9 @@ static int shutdown_cache(struct kmem_cache *s)
#ifdef SLAB_SUPPORTS_SYSFS
sysfs_slab_unlink(s);
#endif
+#ifdef CONFIG_DEBUG_FS
+ debugfs_slab_release(s);
+#endif
list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
schedule_work(&slab_caches_to_rcu_destroy_work);
} else {
@@ -464,6 +470,9 @@ static int shutdown_cache(struct kmem_cache *s)
#else
slab_kmem_cache_release(s);
#endif
+#ifdef CONFIG_DEBUG_FS
+ debugfs_slab_release(s);
+#endif
}
return 0;
diff --git a/mm/slub.c b/mm/slub.c
index 3021ce9..ab7a0d3 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -36,6 +36,7 @@
#include <linux/memcontrol.h>
#include <linux/random.h>
+#include <linux/debugfs.h>
#include <trace/events/kmem.h>
#include "internal.h"
@@ -225,6 +226,15 @@ static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
{ return 0; }
#endif
+#ifdef CONFIG_DEBUG_FS
+static void debugfs_slab_add(struct kmem_cache *);
+static int debugfs_slab_alias(struct kmem_cache *, const char *);
+#else
+static inline void debugfs_slab_add(struct kmem_cache *s) { }
+static inline int debugfs_slab_alias(struct kmem_cache *s, const char *p)
+ { return 0; }
+#endif
+
static inline void stat(const struct kmem_cache *s, enum stat_item si)
{
#ifdef CONFIG_SLUB_STATS
@@ -4521,6 +4531,8 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
s->refcount--;
s = NULL;
}
+
+ debugfs_slab_alias(s, name);
}
return s;
@@ -4542,6 +4554,8 @@ int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
if (err)
__kmem_cache_release(s);
+ debugfs_slab_add(s);
+
return err;
}
@@ -4682,6 +4696,8 @@ static long validate_slab_cache(struct kmem_cache *s)
return count;
}
+
+#ifdef CONFIG_DEBUG_FS
/*
* Generate lists of code addresses where slabcache objects are allocated
* and freed.
@@ -4705,6 +4721,8 @@ struct loc_track {
struct location *loc;
};
+static struct dentry *slab_debugfs_root;
+
static void free_loc_track(struct loc_track *t)
{
if (t->max)
@@ -4822,10 +4840,9 @@ static void process_slab(struct loc_track *t, struct kmem_cache *s,
put_map(map);
}
-static int list_locations(struct kmem_cache *s, char *buf,
+static int list_locations(struct seq_file *seq, struct kmem_cache *s,
enum track_item alloc)
{
- int len = 0;
unsigned long i;
struct loc_track t = { 0, 0, NULL };
int node;
@@ -4833,7 +4850,8 @@ static int list_locations(struct kmem_cache *s, char *buf,
if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
GFP_KERNEL)) {
- return sysfs_emit(buf, "Out of memory\n");
+ seq_puts(seq, "Out of memory\n");
+ return -ENOMEM;
}
/* Push back cpu slabs */
flush_all(s);
@@ -4856,46 +4874,46 @@ static int list_locations(struct kmem_cache *s, char *buf,
for (i = 0; i < t.count; i++) {
struct location *l = &t.loc[i];
- len += sysfs_emit_at(buf, len, "%7ld ", l->count);
+ seq_printf(seq, "%7ld ", l->count);
if (l->addr)
- len += sysfs_emit_at(buf, len, "%pS", (void *)l->addr);
+ seq_printf(seq, "%pS", (void *)l->addr);
else
- len += sysfs_emit_at(buf, len, "<not-available>");
+ seq_puts(seq, "<not-available>");
if (l->sum_time != l->min_time)
- len += sysfs_emit_at(buf, len, " age=%ld/%ld/%ld",
+ seq_printf(seq, " age=%ld/%ld/%ld",
l->min_time,
(long)div_u64(l->sum_time,
l->count),
l->max_time);
else
- len += sysfs_emit_at(buf, len, " age=%ld", l->min_time);
+ seq_printf(seq, " age=%ld", l->min_time);
if (l->min_pid != l->max_pid)
- len += sysfs_emit_at(buf, len, " pid=%ld-%ld",
+ seq_printf(seq, " pid=%ld-%ld",
l->min_pid, l->max_pid);
else
- len += sysfs_emit_at(buf, len, " pid=%ld",
+ seq_printf(seq, " pid=%ld",
l->min_pid);
if (num_online_cpus() > 1 &&
!cpumask_empty(to_cpumask(l->cpus)))
- len += sysfs_emit_at(buf, len, " cpus=%*pbl",
+ seq_printf(seq, " cpus=%*pbl",
cpumask_pr_args(to_cpumask(l->cpus)));
if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
- len += sysfs_emit_at(buf, len, " nodes=%*pbl",
+ seq_printf(seq, " nodes=%*pbl",
nodemask_pr_args(&l->nodes));
- len += sysfs_emit_at(buf, len, "\n");
+ seq_puts(seq, "\n");
}
free_loc_track(&t);
if (!t.count)
- len += sysfs_emit_at(buf, len, "No data\n");
+ seq_puts(seq, "No data\n");
- return len;
+ return 0;
}
#endif /* CONFIG_SLUB_DEBUG */
@@ -5348,17 +5366,23 @@ SLAB_ATTR(validate);
static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
{
- if (!(s->flags & SLAB_STORE_USER))
- return -ENOSYS;
- return list_locations(s, buf, TRACK_ALLOC);
+ int len = 0;
+
+ len += sprintf(buf, "Deprecated, use the equvalent under");
+ len += sprintf(buf, "/sys/kernel/debug/slab/%s/alloc_calls", s->name);
+
+ return len;
}
SLAB_ATTR_RO(alloc_calls);
static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
{
- if (!(s->flags & SLAB_STORE_USER))
- return -ENOSYS;
- return list_locations(s, buf, TRACK_FREE);
+ int len = 0;
+
+ len += sprintf(buf, "Deprecated, use the equvalent under");
+ len += sprintf(buf, "/sys/kernel/debug/slab/%s/free_calls", s->name);
+
+ return len;
}
SLAB_ATTR_RO(free_calls);
#endif /* CONFIG_SLUB_DEBUG */
@@ -5814,6 +5838,142 @@ static int __init slab_sysfs_init(void)
__initcall(slab_sysfs_init);
#endif /* CONFIG_SYSFS */
+#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
+static int debugfs_slab_alias(struct kmem_cache *s, const char *name)
+{
+ struct saved_alias *al;
+
+ if (slab_state == FULL) {
+ /*
+ * If we have a leftover link then remove it.
+ */
+ debugfs_remove(s->slab_cache_dentry);
+ s->slab_cache_dentry = debugfs_create_symlink(name, slab_debugfs_root, NULL);
+ return IS_ERR(s->slab_cache_dentry);
+ }
+
+ al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
+ if (!al)
+ return -ENOMEM;
+
+ al->s = s;
+ al->name = name;
+ al->next = alias_list;
+ alias_list = al;
+ return 0;
+}
+
+static int slab_debug_trace(struct seq_file *seq, void *ignored)
+{
+ struct kmem_cache *s = seq->private;
+
+ if (!(s->flags & SLAB_STORE_USER))
+ return 0;
+
+ if (strcmp(seq->file->f_path.dentry->d_name.name, "alloc_trace") == 0)
+ return list_locations(seq, s, TRACK_ALLOC);
+ else
+ return list_locations(seq, s, TRACK_FREE);
+
+ return 0;
+}
+
+static int slab_debug_trace_open(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, slab_debug_trace,
+ file_inode(filp)->i_private);
+}
+
+static const struct file_operations slab_debug_fops = {
+ .open = slab_debug_trace_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static void debugfs_slab_add(struct kmem_cache *s)
+{
+ const char *name;
+ int unmergeable = slab_unmergeable(s);
+
+ if (unlikely(!slab_debugfs_root))
+ return;
+
+ if (!unmergeable && disable_higher_order_debug &&
+ (slub_debug & DEBUG_METADATA_FLAGS))
+ unmergeable = 1;
+
+ if (unmergeable) {
+ /*
+ * Slabcache can never be merged so we can use the name proper.
+ * This is typically the case for debug situations. In that
+ * case we can catch duplicate names easily.
+ */
+ debugfs_remove(s->slab_cache_dentry);
+ name = s->name;
+ } else {
+ /*
+ * Create a unique name for the slab as a target
+ * for the symlinks.
+ */
+ name = create_unique_id(s);
+ }
+
+ s->slab_cache_dentry = debugfs_create_dir(s->name, slab_debugfs_root);
+ if (!IS_ERR(s->slab_cache_dentry)) {
+ debugfs_create_file("alloc_trace", 0400,
+ s->slab_cache_dentry, s, &slab_debug_fops);
+
+ debugfs_create_file("free_trace", 0400,
+ s->slab_cache_dentry, s, &slab_debug_fops);
+ }
+
+ if (!unmergeable) {
+ /* Setup first alias */
+ debugfs_slab_alias(s, s->name);
+ }
+}
+
+void debugfs_slab_release(struct kmem_cache *s)
+{
+ if (slab_state >= FULL)
+ debugfs_remove_recursive(s->slab_cache_dentry);
+}
+
+static int __init slab_debugfs_init(void)
+{
+ struct kmem_cache *s;
+ int err;
+
+ slab_debugfs_root = debugfs_create_dir("slab", NULL);
+ if (!IS_ERR(slab_debugfs_root)) {
+
+ slab_state = FULL;
+
+ list_for_each_entry(s, &slab_caches, list)
+ debugfs_slab_add(s);
+ } else {
+ pr_err("Cannot create slab debugfs.\n");
+ return IS_ERR(slab_debugfs_root);
+ }
+
+ while (alias_list) {
+ struct saved_alias *al = alias_list;
+
+ alias_list = alias_list->next;
+
+ err = debugfs_slab_alias(al->s, al->name);
+ if (err)
+ pr_err("SLUB: Unable to add boot slab alias %s to debugfs\n",
+ al->name);
+ kfree(al);
+ }
+
+ return 0;
+
+}
+__initcall(slab_debugfs_init);
+#endif
/*
* The /proc/slabinfo ABI
*/
--
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