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* [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
@ 2021-06-06 16:14 Faiyaz Mohammed
  2021-06-06 18:44 ` kernel test robot
                   ` (3 more replies)
  0 siblings, 4 replies; 9+ messages in thread
From: Faiyaz Mohammed @ 2021-06-06 16:14 UTC (permalink / raw)
  To: cl, penberg, rientjes, iamjoonsoo.kim, akpm, vbabka, linux-mm,
	linux-kernel, greg, glittao
  Cc: vinmenon, Faiyaz Mohammed

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.

Debugfs cache will be created if SLAB_STORE_USER flag is set.

Rename the alloc_calls/free_calls to alloc_traces/free_traces,
to be inline with what it does.

Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
---
 mm/slab.h        |   8 ++
 mm/slab_common.c |   2 +
 mm/slub.c        | 292 +++++++++++++++++++++++++++++++++++++------------------
 3 files changed, 209 insertions(+), 93 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index 18c1927..3b60925 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -630,6 +630,14 @@ static inline bool slab_want_init_on_free(struct kmem_cache *c)
 	return false;
 }
 
+#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
+void debugfs_slab_release(struct kmem_cache *);
+#else
+static inline void debugfs_slab_release(struct kmem_cache *s)
+{
+}
+#endif
+
 #ifdef CONFIG_PRINTK
 #define KS_ADDRS_COUNT 16
 struct kmem_obj_info {
diff --git a/mm/slab_common.c b/mm/slab_common.c
index a4a5714..ee5456f 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -449,6 +449,7 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
 	rcu_barrier();
 
 	list_for_each_entry_safe(s, s2, &to_destroy, list) {
+		debugfs_slab_release(s);
 		kfence_shutdown_cache(s);
 #ifdef SLAB_SUPPORTS_SYSFS
 		sysfs_slab_release(s);
@@ -476,6 +477,7 @@ static int shutdown_cache(struct kmem_cache *s)
 		schedule_work(&slab_caches_to_rcu_destroy_work);
 	} else {
 		kfence_shutdown_cache(s);
+		debugfs_slab_release(s);
 #ifdef SLAB_SUPPORTS_SYSFS
 		sysfs_slab_unlink(s);
 		sysfs_slab_release(s);
diff --git a/mm/slub.c b/mm/slub.c
index 3f96e09..974c42bd 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 +226,12 @@ static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
 							{ return 0; }
 #endif
 
+#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
+static void debugfs_slab_add(struct kmem_cache *);
+#else
+static inline void debugfs_slab_add(struct kmem_cache *s) { }
+#endif
+
 static inline void stat(const struct kmem_cache *s, enum stat_item si)
 {
 #ifdef CONFIG_SLUB_STATS
@@ -4546,6 +4553,9 @@ int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
 	if (err)
 		__kmem_cache_release(s);
 
+	if (s->flags & SLAB_STORE_USER)
+		debugfs_slab_add(s);
+
 	return err;
 }
 
@@ -4686,6 +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.
@@ -4709,6 +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)
@@ -4825,82 +4839,7 @@ static void process_slab(struct loc_track *t, struct kmem_cache *s,
 			add_location(t, s, get_track(s, p, alloc));
 	put_map(map);
 }
-
-static int list_locations(struct kmem_cache *s, char *buf,
-			  enum track_item alloc)
-{
-	int len = 0;
-	unsigned long i;
-	struct loc_track t = { 0, 0, NULL };
-	int node;
-	struct kmem_cache_node *n;
-
-	if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
-			     GFP_KERNEL)) {
-		return sysfs_emit(buf, "Out of memory\n");
-	}
-	/* Push back cpu slabs */
-	flush_all(s);
-
-	for_each_kmem_cache_node(s, node, n) {
-		unsigned long flags;
-		struct page *page;
-
-		if (!atomic_long_read(&n->nr_slabs))
-			continue;
-
-		spin_lock_irqsave(&n->list_lock, flags);
-		list_for_each_entry(page, &n->partial, slab_list)
-			process_slab(&t, s, page, alloc);
-		list_for_each_entry(page, &n->full, slab_list)
-			process_slab(&t, s, page, alloc);
-		spin_unlock_irqrestore(&n->list_lock, flags);
-	}
-
-	for (i = 0; i < t.count; i++) {
-		struct location *l = &t.loc[i];
-
-		len += sysfs_emit_at(buf, len, "%7ld ", l->count);
-
-		if (l->addr)
-			len += sysfs_emit_at(buf, len, "%pS", (void *)l->addr);
-		else
-			len += sysfs_emit_at(buf, len, "<not-available>");
-
-		if (l->sum_time != l->min_time)
-			len += sysfs_emit_at(buf, len, " 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);
-
-		if (l->min_pid != l->max_pid)
-			len += sysfs_emit_at(buf, len, " pid=%ld-%ld",
-					     l->min_pid, l->max_pid);
-		else
-			len += sysfs_emit_at(buf, len, " pid=%ld",
-					     l->min_pid);
-
-		if (num_online_cpus() > 1 &&
-		    !cpumask_empty(to_cpumask(l->cpus)))
-			len += sysfs_emit_at(buf, len, " 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",
-					     nodemask_pr_args(&l->nodes));
-
-		len += sysfs_emit_at(buf, len, "\n");
-	}
-
-	free_loc_track(&t);
-	if (!t.count)
-		len += sysfs_emit_at(buf, len, "No data\n");
-
-	return len;
-}
+#endif  /* CONFIG_DEBUG_FS   */
 #endif	/* CONFIG_SLUB_DEBUG */
 
 #ifdef SLUB_RESILIENCY_TEST
@@ -5350,21 +5289,6 @@ static ssize_t validate_store(struct kmem_cache *s,
 }
 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);
-}
-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);
-}
-SLAB_ATTR_RO(free_calls);
 #endif /* CONFIG_SLUB_DEBUG */
 
 #ifdef CONFIG_FAILSLAB
@@ -5528,8 +5452,6 @@ static struct attribute *slab_attrs[] = {
 	&poison_attr.attr,
 	&store_user_attr.attr,
 	&validate_attr.attr,
-	&alloc_calls_attr.attr,
-	&free_calls_attr.attr,
 #endif
 #ifdef CONFIG_ZONE_DMA
 	&cache_dma_attr.attr,
@@ -5818,6 +5740,190 @@ 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 slab_debugfs_show(struct seq_file *seq, void *v)
+{
+
+	struct location *l;
+	unsigned int idx = *(unsigned int *)v;
+	struct loc_track *t = seq->private;
+
+	if (idx < t->count) {
+		l = &t->loc[idx];
+
+		seq_printf(seq, "%7ld ", l->count);
+
+		if (l->addr)
+			seq_printf(seq, "%pS", (void *)l->addr);
+		else
+			seq_puts(seq, "<not-available>");
+
+		if (l->sum_time != l->min_time) {
+			seq_printf(seq, " age=%ld/%ld/%ld",
+				l->min_time,
+				(long)div_u64(l->sum_time, l->count),
+				l->max_time);
+		} else
+			seq_printf(seq, " age=%ld",
+				l->min_time);
+
+		if (l->min_pid != l->max_pid)
+			seq_printf(seq, " pid=%ld-%ld",
+				l->min_pid, l->max_pid);
+		else
+			seq_printf(seq, " pid=%ld",
+				l->min_pid);
+
+		if (num_online_cpus() > 1 &&
+				!cpumask_empty(to_cpumask(l->cpus)))
+			seq_printf(seq, " cpus=%*pbl",
+				 cpumask_pr_args(to_cpumask(l->cpus)));
+
+		if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
+			seq_printf(seq, " nodes=%*pbl",
+				 nodemask_pr_args(&l->nodes));
+
+		seq_puts(seq, "\n");
+	}
+
+	if (!idx && !t->count)
+		seq_puts(seq, "No data\n");
+
+	return 0;
+}
+
+static void slab_debugfs_stop(struct seq_file *seq, void *v)
+{
+	kfree(v);
+}
+
+static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
+{
+	loff_t *spos = v;
+	struct loc_track *t = seq->private;
+
+	if (*ppos < t->count) {
+		*ppos = ++*spos;
+		return spos;
+	}
+	*ppos = ++*spos;
+	return NULL;
+}
+
+static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
+{
+	loff_t *spos = kmalloc(sizeof(loff_t), GFP_KERNEL);
+
+	if (!spos)
+		return NULL;
+
+	*spos = *ppos;
+	return spos;
+}
+
+static const struct seq_operations slab_debugfs_sops = {
+	.start  = slab_debugfs_start,
+	.next   = slab_debugfs_next,
+	.stop   = slab_debugfs_stop,
+	.show   = slab_debugfs_show
+};
+static int slab_debug_trace_open(struct inode *inode, struct file *filep)
+{
+
+	struct kmem_cache_node *n;
+	enum track_item alloc;
+	int node;
+	struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
+						sizeof(struct loc_track));
+	struct kmem_cache *s = file_inode(filep)->i_private;
+
+	if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
+		alloc =  TRACK_ALLOC;
+	else
+		alloc =  TRACK_FREE;
+
+	if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
+		pr_err("Out of memory\n");
+		return -ENOMEM;
+	}
+
+	/* Push back cpu slabs */
+	flush_all(s);
+
+	for_each_kmem_cache_node(s, node, n) {
+		unsigned long flags;
+		struct page *page;
+
+		if (!atomic_long_read(&n->nr_slabs))
+			continue;
+
+		spin_lock_irqsave(&n->list_lock, flags);
+		list_for_each_entry(page, &n->partial, slab_list)
+			process_slab(t, s, page, alloc);
+		list_for_each_entry(page, &n->full, slab_list)
+			process_slab(t, s, page, alloc);
+			spin_unlock_irqrestore(&n->list_lock, flags);
+	}
+
+	return 0;
+}
+
+static int slab_debug_trace_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+	struct loc_track *t = seq->private;
+
+	free_loc_track(t);
+	kfree(seq->private);
+	seq->private = NULL;
+	return seq_release(inode, file);
+}
+
+static const struct file_operations slab_debugfs_fops = {
+	.open    = slab_debug_trace_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = slab_debug_trace_release,
+};
+
+
+static void debugfs_slab_add(struct kmem_cache *s)
+{
+	struct dentry *slab_cache_dir;
+
+	if (unlikely(!slab_debugfs_root))
+		return;
+
+	slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
+
+	debugfs_create_file("alloc_traces", 0400,
+		slab_cache_dir, s, &slab_debugfs_fops);
+
+	debugfs_create_file("free_traces", 0400,
+		slab_cache_dir, s, &slab_debugfs_fops);
+}
+
+void debugfs_slab_release(struct kmem_cache *s)
+{
+	debugfs_remove_recursive(debugfs_lookup(s->name,
+					slab_debugfs_root));
+}
+
+static int __init slab_debugfs_init(void)
+{
+	struct kmem_cache *s;
+
+	slab_debugfs_root = debugfs_create_dir("slab", NULL);
+
+	list_for_each_entry(s, &slab_caches, list)
+		if (s->flags & SLAB_STORE_USER)
+			debugfs_slab_add(s);
+
+	return 0;
+
+}
+__initcall(slab_debugfs_init);
+#endif
 /*
  * The /proc/slabinfo ABI
  */
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
  2021-06-06 16:14 [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs Faiyaz Mohammed
@ 2021-06-06 18:44 ` kernel test robot
  2021-06-06 20:31 ` Andy Shevchenko
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 9+ messages in thread
From: kernel test robot @ 2021-06-06 18:44 UTC (permalink / raw)
  To: Faiyaz Mohammed, cl, penberg, rientjes, iamjoonsoo.kim, akpm,
	vbabka, linux-mm, linux-kernel, greg, glittao
  Cc: kbuild-all

[-- Attachment #1: Type: text/plain, Size: 9305 bytes --]

Hi Faiyaz,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on v5.13-rc4]
[cannot apply to hnaz-linux-mm/master next-20210604]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Faiyaz-Mohammed/mm-slub-move-sysfs-slab-alloc-free-interfaces-to-debugfs/20210607-001659
base:    8124c8a6b35386f73523d27eacb71b5364a68c4c
config: sparc-randconfig-r003-20210606 (attached as .config)
compiler: sparc64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/f7385626eb41e6154132519bd9b836f91eb7f93c
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Faiyaz-Mohammed/mm-slub-move-sysfs-slab-alloc-free-interfaces-to-debugfs/20210607-001659
        git checkout f7385626eb41e6154132519bd9b836f91eb7f93c
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sparc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/linux/preempt.h:11,
                    from include/linux/spinlock.h:51,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:6,
                    from include/linux/mm.h:10,
                    from mm/slub.c:13:
   mm/slub.c: In function 'slab_debug_trace_open':
>> include/linux/list.h:628:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     628 |  for (pos = list_first_entry(head, typeof(*pos), member); \
         |  ^~~
   mm/slub.c:5863:3: note: in expansion of macro 'list_for_each_entry'
    5863 |   list_for_each_entry(page, &n->full, slab_list)
         |   ^~~~~~~~~~~~~~~~~~~
   mm/slub.c:5865:4: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
    5865 |    spin_unlock_irqrestore(&n->list_lock, flags);
         |    ^~~~~~~~~~~~~~~~~~~~~~


vim +/for +628 include/linux/list.h

6d7581e62f8be4 Jiri Pirko      2013-05-29  548  
008208c6b26f21 Oleg Nesterov   2013-11-12  549  /**
008208c6b26f21 Oleg Nesterov   2013-11-12  550   * list_next_entry - get the next element in list
008208c6b26f21 Oleg Nesterov   2013-11-12  551   * @pos:	the type * to cursor
3943f42c11896c Andrey Utkin    2014-11-14  552   * @member:	the name of the list_head within the struct.
008208c6b26f21 Oleg Nesterov   2013-11-12  553   */
008208c6b26f21 Oleg Nesterov   2013-11-12  554  #define list_next_entry(pos, member) \
008208c6b26f21 Oleg Nesterov   2013-11-12  555  	list_entry((pos)->member.next, typeof(*(pos)), member)
008208c6b26f21 Oleg Nesterov   2013-11-12  556  
008208c6b26f21 Oleg Nesterov   2013-11-12  557  /**
008208c6b26f21 Oleg Nesterov   2013-11-12  558   * list_prev_entry - get the prev element in list
008208c6b26f21 Oleg Nesterov   2013-11-12  559   * @pos:	the type * to cursor
3943f42c11896c Andrey Utkin    2014-11-14  560   * @member:	the name of the list_head within the struct.
008208c6b26f21 Oleg Nesterov   2013-11-12  561   */
008208c6b26f21 Oleg Nesterov   2013-11-12  562  #define list_prev_entry(pos, member) \
008208c6b26f21 Oleg Nesterov   2013-11-12  563  	list_entry((pos)->member.prev, typeof(*(pos)), member)
008208c6b26f21 Oleg Nesterov   2013-11-12  564  
^1da177e4c3f41 Linus Torvalds  2005-04-16  565  /**
^1da177e4c3f41 Linus Torvalds  2005-04-16  566   * list_for_each	-	iterate over a list
8e3a67a99231f9 Randy Dunlap    2006-06-25  567   * @pos:	the &struct list_head to use as a loop cursor.
^1da177e4c3f41 Linus Torvalds  2005-04-16  568   * @head:	the head for your list.
^1da177e4c3f41 Linus Torvalds  2005-04-16  569   */
^1da177e4c3f41 Linus Torvalds  2005-04-16  570  #define list_for_each(pos, head) \
e66eed651fd18a Linus Torvalds  2011-05-19  571  	for (pos = (head)->next; pos != (head); pos = pos->next)
^1da177e4c3f41 Linus Torvalds  2005-04-16  572  
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  573  /**
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  574   * list_for_each_continue - continue iteration over a list
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  575   * @pos:	the &struct list_head to use as a loop cursor.
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  576   * @head:	the head for your list.
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  577   *
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  578   * Continue to iterate over a list, continuing after the current position.
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  579   */
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  580  #define list_for_each_continue(pos, head) \
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  581  	for (pos = pos->next; pos != (head); pos = pos->next)
28ca0d6d39ab1d Pavel Begunkov  2019-11-29  582  
^1da177e4c3f41 Linus Torvalds  2005-04-16  583  /**
^1da177e4c3f41 Linus Torvalds  2005-04-16  584   * list_for_each_prev	-	iterate over a list backwards
8e3a67a99231f9 Randy Dunlap    2006-06-25  585   * @pos:	the &struct list_head to use as a loop cursor.
^1da177e4c3f41 Linus Torvalds  2005-04-16  586   * @head:	the head for your list.
^1da177e4c3f41 Linus Torvalds  2005-04-16  587   */
^1da177e4c3f41 Linus Torvalds  2005-04-16  588  #define list_for_each_prev(pos, head) \
e66eed651fd18a Linus Torvalds  2011-05-19  589  	for (pos = (head)->prev; pos != (head); pos = pos->prev)
^1da177e4c3f41 Linus Torvalds  2005-04-16  590  
^1da177e4c3f41 Linus Torvalds  2005-04-16  591  /**
^1da177e4c3f41 Linus Torvalds  2005-04-16  592   * list_for_each_safe - iterate over a list safe against removal of list entry
8e3a67a99231f9 Randy Dunlap    2006-06-25  593   * @pos:	the &struct list_head to use as a loop cursor.
^1da177e4c3f41 Linus Torvalds  2005-04-16  594   * @n:		another &struct list_head to use as temporary storage
^1da177e4c3f41 Linus Torvalds  2005-04-16  595   * @head:	the head for your list.
^1da177e4c3f41 Linus Torvalds  2005-04-16  596   */
^1da177e4c3f41 Linus Torvalds  2005-04-16  597  #define list_for_each_safe(pos, n, head) \
^1da177e4c3f41 Linus Torvalds  2005-04-16  598  	for (pos = (head)->next, n = pos->next; pos != (head); \
^1da177e4c3f41 Linus Torvalds  2005-04-16  599  		pos = n, n = pos->next)
^1da177e4c3f41 Linus Torvalds  2005-04-16  600  
37c42524d60906 Denis V. Lunev  2007-10-16  601  /**
8f731f7d83d6c6 Randy Dunlap    2007-10-18  602   * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
37c42524d60906 Denis V. Lunev  2007-10-16  603   * @pos:	the &struct list_head to use as a loop cursor.
37c42524d60906 Denis V. Lunev  2007-10-16  604   * @n:		another &struct list_head to use as temporary storage
37c42524d60906 Denis V. Lunev  2007-10-16  605   * @head:	the head for your list.
37c42524d60906 Denis V. Lunev  2007-10-16  606   */
37c42524d60906 Denis V. Lunev  2007-10-16  607  #define list_for_each_prev_safe(pos, n, head) \
37c42524d60906 Denis V. Lunev  2007-10-16  608  	for (pos = (head)->prev, n = pos->prev; \
e66eed651fd18a Linus Torvalds  2011-05-19  609  	     pos != (head); \
37c42524d60906 Denis V. Lunev  2007-10-16  610  	     pos = n, n = pos->prev)
37c42524d60906 Denis V. Lunev  2007-10-16  611  
e130816164e244 Andy Shevchenko 2020-10-15  612  /**
e130816164e244 Andy Shevchenko 2020-10-15  613   * list_entry_is_head - test if the entry points to the head of the list
e130816164e244 Andy Shevchenko 2020-10-15  614   * @pos:	the type * to cursor
e130816164e244 Andy Shevchenko 2020-10-15  615   * @head:	the head for your list.
e130816164e244 Andy Shevchenko 2020-10-15  616   * @member:	the name of the list_head within the struct.
e130816164e244 Andy Shevchenko 2020-10-15  617   */
e130816164e244 Andy Shevchenko 2020-10-15  618  #define list_entry_is_head(pos, head, member)				\
e130816164e244 Andy Shevchenko 2020-10-15  619  	(&pos->member == (head))
e130816164e244 Andy Shevchenko 2020-10-15  620  
^1da177e4c3f41 Linus Torvalds  2005-04-16  621  /**
^1da177e4c3f41 Linus Torvalds  2005-04-16  622   * list_for_each_entry	-	iterate over list of given type
8e3a67a99231f9 Randy Dunlap    2006-06-25  623   * @pos:	the type * to use as a loop cursor.
^1da177e4c3f41 Linus Torvalds  2005-04-16  624   * @head:	the head for your list.
3943f42c11896c Andrey Utkin    2014-11-14  625   * @member:	the name of the list_head within the struct.
^1da177e4c3f41 Linus Torvalds  2005-04-16  626   */
^1da177e4c3f41 Linus Torvalds  2005-04-16  627  #define list_for_each_entry(pos, head, member)				\
93be3c2eb3371f Oleg Nesterov   2013-11-12 @628  	for (pos = list_first_entry(head, typeof(*pos), member);	\
e130816164e244 Andy Shevchenko 2020-10-15  629  	     !list_entry_is_head(pos, head, member);			\
8120e2e5141a42 Oleg Nesterov   2013-11-12  630  	     pos = list_next_entry(pos, member))
^1da177e4c3f41 Linus Torvalds  2005-04-16  631  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 37792 bytes --]

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
  2021-06-06 16:14 [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs Faiyaz Mohammed
  2021-06-06 18:44 ` kernel test robot
@ 2021-06-06 20:31 ` Andy Shevchenko
  2021-06-07  2:40   ` Faiyaz Mohammed
  2021-06-07 13:54   ` Faiyaz Mohammed
  2021-06-07  2:01 ` Faiyaz Mohammed
  2021-06-07 10:12 ` Vlastimil Babka
  3 siblings, 2 replies; 9+ messages in thread
From: Andy Shevchenko @ 2021-06-06 20:31 UTC (permalink / raw)
  To: Faiyaz Mohammed
  Cc: Christoph Lameter, Pekka Enberg, David Rientjes, Joonsoo Kim,
	Andrew Morton, Vlastimil Babka, linux-mm,
	Linux Kernel Mailing List, Greg KH, glittao, vinmenon

On Sun, Jun 6, 2021 at 7:16 PM Faiyaz Mohammed <faiyazm@codeaurora.org> wrote:
>
> 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

limitation

> to "one value per file" rule.
>
> To overcome this issues, move the alloc_calls and free_calls implemeation

implementation

> to debugfs.
>
> Debugfs cache will be created if SLAB_STORE_USER flag is set.
>
> Rename the alloc_calls/free_calls to alloc_traces/free_traces,
> to be inline with what it does.

...

> +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
> +void debugfs_slab_release(struct kmem_cache *);
> +#else

> +static inline void debugfs_slab_release(struct kmem_cache *s)
> +{
> +}

It can be one line.

> +#endif

...


> +               if (l->sum_time != l->min_time) {
> +                       seq_printf(seq, " age=%ld/%ld/%ld",
> +                               l->min_time,

> +                               (long)div_u64(l->sum_time, l->count),

Hmm... Why is the cast needed here?

> +                               l->max_time);
> +               } else
> +                       seq_printf(seq, " age=%ld",
> +                               l->min_time);

...

> +               if (num_online_cpus() > 1 &&
> +                               !cpumask_empty(to_cpumask(l->cpus)))

One line?

...

> +static const struct seq_operations slab_debugfs_sops = {
> +       .start  = slab_debugfs_start,
> +       .next   = slab_debugfs_next,
> +       .stop   = slab_debugfs_stop,

> +       .show   = slab_debugfs_show

Leave a comma here. It might not be the last one in the future.

> +};

+ blank line?

> +static int slab_debug_trace_open(struct inode *inode, struct file *filep)
> +{

...

> +static const struct file_operations slab_debugfs_fops = {
> +       .open    = slab_debug_trace_open,
> +       .read    = seq_read,
> +       .llseek  = seq_lseek,
> +       .release = slab_debug_trace_release,
> +};
> +
> +

One blank line is enough.

...

> +       debugfs_remove_recursive(debugfs_lookup(s->name,
> +                                       slab_debugfs_root));

One line?

-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
  2021-06-06 16:14 [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs Faiyaz Mohammed
  2021-06-06 18:44 ` kernel test robot
  2021-06-06 20:31 ` Andy Shevchenko
@ 2021-06-07  2:01 ` Faiyaz Mohammed
  2021-06-07 10:12 ` Vlastimil Babka
  3 siblings, 0 replies; 9+ messages in thread
From: Faiyaz Mohammed @ 2021-06-07  2:01 UTC (permalink / raw)
  To: cl, penberg, rientjes, iamjoonsoo.kim, akpm, vbabka, linux-mm,
	linux-kernel, greg, glittao
  Cc: vinmenon



On 6/6/2021 9:44 PM, Faiyaz Mohammed wrote:
> 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.
> 
> Debugfs cache will be created if SLAB_STORE_USER flag is set.
> 
> Rename the alloc_calls/free_calls to alloc_traces/free_traces,
> to be inline with what it does.
> 
> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
> ---
>  mm/slab.h        |   8 ++
>  mm/slab_common.c |   2 +
>  mm/slub.c        | 292 +++++++++++++++++++++++++++++++++++++------------------
>  3 files changed, 209 insertions(+), 93 deletions(-)
> 
> diff --git a/mm/slab.h b/mm/slab.h
> index 18c1927..3b60925 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -630,6 +630,14 @@ static inline bool slab_want_init_on_free(struct kmem_cache *c)
>  	return false;
>  }
>  
> +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
> +void debugfs_slab_release(struct kmem_cache *);
> +#else
> +static inline void debugfs_slab_release(struct kmem_cache *s)
> +{
> +}
> +#endif
> +
>  #ifdef CONFIG_PRINTK
>  #define KS_ADDRS_COUNT 16
>  struct kmem_obj_info {
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index a4a5714..ee5456f 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -449,6 +449,7 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
>  	rcu_barrier();
>  
>  	list_for_each_entry_safe(s, s2, &to_destroy, list) {
> +		debugfs_slab_release(s);
>  		kfence_shutdown_cache(s);
>  #ifdef SLAB_SUPPORTS_SYSFS
>  		sysfs_slab_release(s);
> @@ -476,6 +477,7 @@ static int shutdown_cache(struct kmem_cache *s)
>  		schedule_work(&slab_caches_to_rcu_destroy_work);
>  	} else {
>  		kfence_shutdown_cache(s);
> +		debugfs_slab_release(s);
>  #ifdef SLAB_SUPPORTS_SYSFS
>  		sysfs_slab_unlink(s);
>  		sysfs_slab_release(s);
> diff --git a/mm/slub.c b/mm/slub.c
> index 3f96e09..974c42bd 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 +226,12 @@ static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
>  							{ return 0; }
>  #endif
>  
> +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
> +static void debugfs_slab_add(struct kmem_cache *);
> +#else
> +static inline void debugfs_slab_add(struct kmem_cache *s) { }
> +#endif
> +
>  static inline void stat(const struct kmem_cache *s, enum stat_item si)
>  {
>  #ifdef CONFIG_SLUB_STATS
> @@ -4546,6 +4553,9 @@ int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
>  	if (err)
>  		__kmem_cache_release(s);
>  
> +	if (s->flags & SLAB_STORE_USER)
> +		debugfs_slab_add(s);
> +
>  	return err;
>  }
>  
> @@ -4686,6 +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.
> @@ -4709,6 +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)
> @@ -4825,82 +4839,7 @@ static void process_slab(struct loc_track *t, struct kmem_cache *s,
>  			add_location(t, s, get_track(s, p, alloc));
>  	put_map(map);
>  }
> -
> -static int list_locations(struct kmem_cache *s, char *buf,
> -			  enum track_item alloc)
> -{
> -	int len = 0;
> -	unsigned long i;
> -	struct loc_track t = { 0, 0, NULL };
> -	int node;
> -	struct kmem_cache_node *n;
> -
> -	if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
> -			     GFP_KERNEL)) {
> -		return sysfs_emit(buf, "Out of memory\n");
> -	}
> -	/* Push back cpu slabs */
> -	flush_all(s);
> -
> -	for_each_kmem_cache_node(s, node, n) {
> -		unsigned long flags;
> -		struct page *page;
> -
> -		if (!atomic_long_read(&n->nr_slabs))
> -			continue;
> -
> -		spin_lock_irqsave(&n->list_lock, flags);
> -		list_for_each_entry(page, &n->partial, slab_list)
> -			process_slab(&t, s, page, alloc);
> -		list_for_each_entry(page, &n->full, slab_list)
> -			process_slab(&t, s, page, alloc);
> -		spin_unlock_irqrestore(&n->list_lock, flags);
> -	}
> -
> -	for (i = 0; i < t.count; i++) {
> -		struct location *l = &t.loc[i];
> -
> -		len += sysfs_emit_at(buf, len, "%7ld ", l->count);
> -
> -		if (l->addr)
> -			len += sysfs_emit_at(buf, len, "%pS", (void *)l->addr);
> -		else
> -			len += sysfs_emit_at(buf, len, "<not-available>");
> -
> -		if (l->sum_time != l->min_time)
> -			len += sysfs_emit_at(buf, len, " 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);
> -
> -		if (l->min_pid != l->max_pid)
> -			len += sysfs_emit_at(buf, len, " pid=%ld-%ld",
> -					     l->min_pid, l->max_pid);
> -		else
> -			len += sysfs_emit_at(buf, len, " pid=%ld",
> -					     l->min_pid);
> -
> -		if (num_online_cpus() > 1 &&
> -		    !cpumask_empty(to_cpumask(l->cpus)))
> -			len += sysfs_emit_at(buf, len, " 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",
> -					     nodemask_pr_args(&l->nodes));
> -
> -		len += sysfs_emit_at(buf, len, "\n");
> -	}
> -
> -	free_loc_track(&t);
> -	if (!t.count)
> -		len += sysfs_emit_at(buf, len, "No data\n");
> -
> -	return len;
> -}
> +#endif  /* CONFIG_DEBUG_FS   */
>  #endif	/* CONFIG_SLUB_DEBUG */
>  
>  #ifdef SLUB_RESILIENCY_TEST
> @@ -5350,21 +5289,6 @@ static ssize_t validate_store(struct kmem_cache *s,
>  }
>  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);
> -}
> -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);
> -}
> -SLAB_ATTR_RO(free_calls);
>  #endif /* CONFIG_SLUB_DEBUG */
>  
>  #ifdef CONFIG_FAILSLAB
> @@ -5528,8 +5452,6 @@ static struct attribute *slab_attrs[] = {
>  	&poison_attr.attr,
>  	&store_user_attr.attr,
>  	&validate_attr.attr,
> -	&alloc_calls_attr.attr,
> -	&free_calls_attr.attr,
>  #endif
>  #ifdef CONFIG_ZONE_DMA
>  	&cache_dma_attr.attr,
> @@ -5818,6 +5740,190 @@ 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 slab_debugfs_show(struct seq_file *seq, void *v)
> +{
> +
> +	struct location *l;
> +	unsigned int idx = *(unsigned int *)v;
> +	struct loc_track *t = seq->private;
> +
> +	if (idx < t->count) {
> +		l = &t->loc[idx];
> +
> +		seq_printf(seq, "%7ld ", l->count);
> +
> +		if (l->addr)
> +			seq_printf(seq, "%pS", (void *)l->addr);
> +		else
> +			seq_puts(seq, "<not-available>");
> +
> +		if (l->sum_time != l->min_time) {
> +			seq_printf(seq, " age=%ld/%ld/%ld",
> +				l->min_time,
> +				(long)div_u64(l->sum_time, l->count),
> +				l->max_time);
> +		} else
> +			seq_printf(seq, " age=%ld",
> +				l->min_time);
> +
> +		if (l->min_pid != l->max_pid)
> +			seq_printf(seq, " pid=%ld-%ld",
> +				l->min_pid, l->max_pid);
> +		else
> +			seq_printf(seq, " pid=%ld",
> +				l->min_pid);
> +
> +		if (num_online_cpus() > 1 &&
> +				!cpumask_empty(to_cpumask(l->cpus)))
> +			seq_printf(seq, " cpus=%*pbl",
> +				 cpumask_pr_args(to_cpumask(l->cpus)));
> +
> +		if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
> +			seq_printf(seq, " nodes=%*pbl",
> +				 nodemask_pr_args(&l->nodes));
> +
> +		seq_puts(seq, "\n");
> +	}
> +
> +	if (!idx && !t->count)
> +		seq_puts(seq, "No data\n");
> +
> +	return 0;
> +}
> +
> +static void slab_debugfs_stop(struct seq_file *seq, void *v)
> +{
> +	kfree(v);
> +}
> +
> +static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
> +{
> +	loff_t *spos = v;
> +	struct loc_track *t = seq->private;
> +
> +	if (*ppos < t->count) {
> +		*ppos = ++*spos;
> +		return spos;
> +	}
> +	*ppos = ++*spos;
> +	return NULL;
> +}
> +
> +static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
> +{
> +	loff_t *spos = kmalloc(sizeof(loff_t), GFP_KERNEL);
> +
> +	if (!spos)
> +		return NULL;
> +
> +	*spos = *ppos;
> +	return spos;
> +}
> +
> +static const struct seq_operations slab_debugfs_sops = {
> +	.start  = slab_debugfs_start,
> +	.next   = slab_debugfs_next,
> +	.stop   = slab_debugfs_stop,
> +	.show   = slab_debugfs_show
> +};
> +static int slab_debug_trace_open(struct inode *inode, struct file *filep)
> +{
> +
> +	struct kmem_cache_node *n;
> +	enum track_item alloc;
> +	int node;
> +	struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
> +						sizeof(struct loc_track));
> +	struct kmem_cache *s = file_inode(filep)->i_private;
> +
> +	if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
> +		alloc =  TRACK_ALLOC;
> +	else
> +		alloc =  TRACK_FREE;
> +
> +	if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
> +		pr_err("Out of memory\n");
> +		return -ENOMEM;
> +	}
> +
> +	/* Push back cpu slabs */
> +	flush_all(s);
> +
> +	for_each_kmem_cache_node(s, node, n) {
> +		unsigned long flags;
> +		struct page *page;
> +
> +		if (!atomic_long_read(&n->nr_slabs))
> +			continue;
> +
> +		spin_lock_irqsave(&n->list_lock, flags);
> +		list_for_each_entry(page, &n->partial, slab_list)
> +			process_slab(t, s, page, alloc);
> +		list_for_each_entry(page, &n->full, slab_list)
> +			process_slab(t, s, page, alloc);
> +			spin_unlock_irqrestore(&n->list_lock, flags);
oh, due to extra tab it moved inside the list_for_ech_entry, will fixed
in next patch version.
> +	}
> +
> +	return 0;
> +}
> +
> +static int slab_debug_trace_release(struct inode *inode, struct file *file)
> +{
> +	struct seq_file *seq = file->private_data;
> +	struct loc_track *t = seq->private;
> +
> +	free_loc_track(t);
> +	kfree(seq->private);
> +	seq->private = NULL;
> +	return seq_release(inode, file);
> +}
> +
> +static const struct file_operations slab_debugfs_fops = {
> +	.open    = slab_debug_trace_open,
> +	.read    = seq_read,
> +	.llseek  = seq_lseek,
> +	.release = slab_debug_trace_release,
> +};
> +
> +
> +static void debugfs_slab_add(struct kmem_cache *s)
> +{
> +	struct dentry *slab_cache_dir;
> +
> +	if (unlikely(!slab_debugfs_root))
> +		return;
> +
> +	slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
> +
> +	debugfs_create_file("alloc_traces", 0400,
> +		slab_cache_dir, s, &slab_debugfs_fops);
> +
> +	debugfs_create_file("free_traces", 0400,
> +		slab_cache_dir, s, &slab_debugfs_fops);
> +}
> +
> +void debugfs_slab_release(struct kmem_cache *s)
> +{
> +	debugfs_remove_recursive(debugfs_lookup(s->name,
> +					slab_debugfs_root));
> +}
> +
> +static int __init slab_debugfs_init(void)
> +{
> +	struct kmem_cache *s;
> +
> +	slab_debugfs_root = debugfs_create_dir("slab", NULL);
> +
> +	list_for_each_entry(s, &slab_caches, list)
> +		if (s->flags & SLAB_STORE_USER)
> +			debugfs_slab_add(s);
> +
> +	return 0;
> +
> +}
> +__initcall(slab_debugfs_init);
> +#endif
>  /*
>   * The /proc/slabinfo ABI
>   */
> 

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
  2021-06-06 20:31 ` Andy Shevchenko
@ 2021-06-07  2:40   ` Faiyaz Mohammed
  2021-06-07  8:42     ` Andy Shevchenko
  2021-06-07 13:54   ` Faiyaz Mohammed
  1 sibling, 1 reply; 9+ messages in thread
From: Faiyaz Mohammed @ 2021-06-07  2:40 UTC (permalink / raw)
  To: Andy Shevchenko
  Cc: Christoph Lameter, Pekka Enberg, David Rientjes, Joonsoo Kim,
	Andrew Morton, Vlastimil Babka, linux-mm,
	Linux Kernel Mailing List, Greg KH, glittao, vinmenon



On 6/7/2021 2:01 AM, Andy Shevchenko wrote:
> On Sun, Jun 6, 2021 at 7:16 PM Faiyaz Mohammed <faiyazm@codeaurora.org> wrote:
>>
>> 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
> 
> limitation
> 
>> to "one value per file" rule.
>>
>> To overcome this issues, move the alloc_calls and free_calls implemeation
> 
> implementation
> 
>> to debugfs.
>>
>> Debugfs cache will be created if SLAB_STORE_USER flag is set.
>>
>> Rename the alloc_calls/free_calls to alloc_traces/free_traces,
>> to be inline with what it does.

> ...
> 
>> +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
>> +void debugfs_slab_release(struct kmem_cache *);
>> +#else
> 
>> +static inline void debugfs_slab_release(struct kmem_cache *s)
>> +{
>> +}
> 
> It can be one line.
> 
>> +#endif
> 
> ...
> 
> 
>> +               if (l->sum_time != l->min_time) {
>> +                       seq_printf(seq, " age=%ld/%ld/%ld",
>> +                               l->min_time,
> 
>> +                               (long)div_u64(l->sum_time, l->count),
> 
> Hmm... Why is the cast needed here?
> 
To avoid below warning while preparing build for arm/32 bit,
"format ‘%ld’ expects argument of type ‘long int’, but argument 4 has
type ‘u64 {aka long long unsigned int}"	.
>> +                               l->max_time);
>> +               } else
>> +                       seq_printf(seq, " age=%ld",
>> +                               l->min_time);
> 
> ...
> 
>> +               if (num_online_cpus() > 1 &&
>> +                               !cpumask_empty(to_cpumask(l->cpus)))
> 
> One line?
> 
> ...
> 
>> +static const struct seq_operations slab_debugfs_sops = {
>> +       .start  = slab_debugfs_start,
>> +       .next   = slab_debugfs_next,
>> +       .stop   = slab_debugfs_stop,
> 
>> +       .show   = slab_debugfs_show
> 
> Leave a comma here. It might not be the last one in the future.
> 
>> +};
> 
> + blank line?
> 
>> +static int slab_debug_trace_open(struct inode *inode, struct file *filep)
>> +{
> 
> ...
> 
>> +static const struct file_operations slab_debugfs_fops = {
>> +       .open    = slab_debug_trace_open,
>> +       .read    = seq_read,
>> +       .llseek  = seq_lseek,
>> +       .release = slab_debug_trace_release,
>> +};
>> +
>> +
> 
> One blank line is enough.
> 
> ...
> 
>> +       debugfs_remove_recursive(debugfs_lookup(s->name,
>> +                                       slab_debugfs_root));
> 
> One line?
> 
Will update other comments in next patch.

Thanks and regards,
Mohammed Faiyaz

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
  2021-06-07  2:40   ` Faiyaz Mohammed
@ 2021-06-07  8:42     ` Andy Shevchenko
  0 siblings, 0 replies; 9+ messages in thread
From: Andy Shevchenko @ 2021-06-07  8:42 UTC (permalink / raw)
  To: Faiyaz Mohammed
  Cc: Christoph Lameter, Pekka Enberg, David Rientjes, Joonsoo Kim,
	Andrew Morton, Vlastimil Babka, linux-mm,
	Linux Kernel Mailing List, Greg KH, glittao, vinmenon

On Mon, Jun 7, 2021 at 5:40 AM Faiyaz Mohammed <faiyazm@codeaurora.org> wrote:
> On 6/7/2021 2:01 AM, Andy Shevchenko wrote:
> > On Sun, Jun 6, 2021 at 7:16 PM Faiyaz Mohammed <faiyazm@codeaurora.org> wrote:

...

> >> +               if (l->sum_time != l->min_time) {
> >> +                       seq_printf(seq, " age=%ld/%ld/%ld",
> >> +                               l->min_time,
> >
> >> +                               (long)div_u64(l->sum_time, l->count),
> >
> > Hmm... Why is the cast needed here?
> >
> To avoid below warning while preparing build for arm/32 bit,
> "format ‘%ld’ expects argument of type ‘long int’, but argument 4 has
> type ‘u64 {aka long long unsigned int}" .

Perhaps use %llu?

> >> +                               l->max_time);
> >> +               } else
> >> +                       seq_printf(seq, " age=%ld",
> >> +                               l->min_time);

-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
  2021-06-06 16:14 [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs Faiyaz Mohammed
                   ` (2 preceding siblings ...)
  2021-06-07  2:01 ` Faiyaz Mohammed
@ 2021-06-07 10:12 ` Vlastimil Babka
  3 siblings, 0 replies; 9+ messages in thread
From: Vlastimil Babka @ 2021-06-07 10:12 UTC (permalink / raw)
  To: Faiyaz Mohammed, cl, penberg, rientjes, iamjoonsoo.kim, akpm,
	linux-mm, linux-kernel, greg, glittao
  Cc: vinmenon

On 6/6/21 6:14 PM, Faiyaz Mohammed wrote:
> 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.
> 
> Debugfs cache will be created if SLAB_STORE_USER flag is set.
> 
> Rename the alloc_calls/free_calls to alloc_traces/free_traces,
> to be inline with what it does.
> 
> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
> ---
>  mm/slab.h        |   8 ++
>  mm/slab_common.c |   2 +
>  mm/slub.c        | 292 +++++++++++++++++++++++++++++++++++++------------------
>  3 files changed, 209 insertions(+), 93 deletions(-)
> 

...

> +static int slab_debug_trace_open(struct inode *inode, struct file *filep)
> +{
> +
> +	struct kmem_cache_node *n;
> +	enum track_item alloc;
> +	int node;
> +	struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
> +						sizeof(struct loc_track));
> +	struct kmem_cache *s = file_inode(filep)->i_private;
> +
> +	if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
> +		alloc =  TRACK_ALLOC;

			^ extra space here?

> +	else
> +		alloc =  TRACK_FREE;

same here

> +
> +	if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
> +		pr_err("Out of memory\n");

Hm I would remove this. It doesn't print any context, so it's not useful to let
users know where/why we ran out of memory. Also if a GFP_KERNEL allocation
fails, there will be a big warning including stacktrace from the page allocator
anyway.

> +		return -ENOMEM;
> +	}
> +
> +	/* Push back cpu slabs */
> +	flush_all(s);
> +
> +	for_each_kmem_cache_node(s, node, n) {
> +		unsigned long flags;
> +		struct page *page;
> +
> +		if (!atomic_long_read(&n->nr_slabs))
> +			continue;
> +
> +		spin_lock_irqsave(&n->list_lock, flags);
> +		list_for_each_entry(page, &n->partial, slab_list)
> +			process_slab(t, s, page, alloc);
> +		list_for_each_entry(page, &n->full, slab_list)
> +			process_slab(t, s, page, alloc);
> +			spin_unlock_irqrestore(&n->list_lock, flags);

At least this is not Python, so it's just a visual flaw :)

> +	}
> +
> +	return 0;
> +}
> +
> +static int slab_debug_trace_release(struct inode *inode, struct file *file)
> +{
> +	struct seq_file *seq = file->private_data;
> +	struct loc_track *t = seq->private;
> +
> +	free_loc_track(t);
> +	kfree(seq->private);
> +	seq->private = NULL;
> +	return seq_release(inode, file);

You can call seq_release_private() instead and deal just with free_loc_track here.

Thanks!
Vlastimil

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
  2021-06-06 20:31 ` Andy Shevchenko
  2021-06-07  2:40   ` Faiyaz Mohammed
@ 2021-06-07 13:54   ` Faiyaz Mohammed
  2021-06-07 16:42     ` Andy Shevchenko
  1 sibling, 1 reply; 9+ messages in thread
From: Faiyaz Mohammed @ 2021-06-07 13:54 UTC (permalink / raw)
  To: Andy Shevchenko
  Cc: Christoph Lameter, Pekka Enberg, David Rientjes, Joonsoo Kim,
	Andrew Morton, Vlastimil Babka, linux-mm,
	Linux Kernel Mailing List, Greg KH, glittao, vinmenon



On 6/7/2021 2:01 AM, Andy Shevchenko wrote:
> On Sun, Jun 6, 2021 at 7:16 PM Faiyaz Mohammed <faiyazm@codeaurora.org> wrote:
>>
>> 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
> 
> limitation
> 
>> to "one value per file" rule.
>>
>> To overcome this issues, move the alloc_calls and free_calls implemeation
> 
> implementation
> 
>> to debugfs.
>>
>> Debugfs cache will be created if SLAB_STORE_USER flag is set.
>>
>> Rename the alloc_calls/free_calls to alloc_traces/free_traces,
>> to be inline with what it does.
> 
> ...
> 
>> +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
>> +void debugfs_slab_release(struct kmem_cache *);
>> +#else
> 
>> +static inline void debugfs_slab_release(struct kmem_cache *s)
>> +{
>> +}
> 
> It can be one line.
> 
>> +#endif
> 
> ...
> 
> 
>> +               if (l->sum_time != l->min_time) {
>> +                       seq_printf(seq, " age=%ld/%ld/%ld",
>> +                               l->min_time,
> 
>> +                               (long)div_u64(l->sum_time, l->count),
> 
> Hmm... Why is the cast needed here?
> 
>> +                               l->max_time);
>> +               } else
>> +                       seq_printf(seq, " age=%ld",
>> +                               l->min_time);
> 
> ...
> 
>> +               if (num_online_cpus() > 1 &&
>> +                               !cpumask_empty(to_cpumask(l->cpus)))
> 
> One line?
> 
I have split the line because it is crossing the 80 columns. In this
case it's okay to cross 80 columns?
> ...
> 
>> +static const struct seq_operations slab_debugfs_sops = {
>> +       .start  = slab_debugfs_start,
>> +       .next   = slab_debugfs_next,
>> +       .stop   = slab_debugfs_stop,
> 
>> +       .show   = slab_debugfs_show
> 
> Leave a comma here. It might not be the last one in the future.
> 
>> +};
> 
> + blank line?
> 
>> +static int slab_debug_trace_open(struct inode *inode, struct file *filep)
>> +{
> 
> ...
> 
>> +static const struct file_operations slab_debugfs_fops = {
>> +       .open    = slab_debug_trace_open,
>> +       .read    = seq_read,
>> +       .llseek  = seq_lseek,
>> +       .release = slab_debug_trace_release,
>> +};
>> +
>> +
> 
> One blank line is enough.
> 
> ...
> 
>> +       debugfs_remove_recursive(debugfs_lookup(s->name,
>> +                                       slab_debugfs_root));
> 
> One line?
> 
Same here!

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs
  2021-06-07 13:54   ` Faiyaz Mohammed
@ 2021-06-07 16:42     ` Andy Shevchenko
  0 siblings, 0 replies; 9+ messages in thread
From: Andy Shevchenko @ 2021-06-07 16:42 UTC (permalink / raw)
  To: Faiyaz Mohammed
  Cc: Christoph Lameter, Pekka Enberg, David Rientjes, Joonsoo Kim,
	Andrew Morton, Vlastimil Babka, linux-mm,
	Linux Kernel Mailing List, Greg KH, glittao, vinmenon

On Mon, Jun 7, 2021 at 4:55 PM Faiyaz Mohammed <faiyazm@codeaurora.org> wrote:
> On 6/7/2021 2:01 AM, Andy Shevchenko wrote:
> > On Sun, Jun 6, 2021 at 7:16 PM Faiyaz Mohammed <faiyazm@codeaurora.org> wrote:

...

> >> +               if (num_online_cpus() > 1 &&
> >> +                               !cpumask_empty(to_cpumask(l->cpus)))
> >
> > One line?
> >
> I have split the line because it is crossing the 80 columns. In this
> case it's okay to cross 80 columns?

For how many characters? If it's 3 or 4 or so, it's fine to have it on
one line. Use common sense here.

...

> >> +       debugfs_remove_recursive(debugfs_lookup(s->name,
> >> +                                       slab_debugfs_root));
> >
> > One line?
> >
> Same here!

Same here.

-- 
With Best Regards,
Andy Shevchenko

^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2021-06-07 16:43 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-06 16:14 [PATCH v10] mm: slub: move sysfs slab alloc/free interfaces to debugfs Faiyaz Mohammed
2021-06-06 18:44 ` kernel test robot
2021-06-06 20:31 ` Andy Shevchenko
2021-06-07  2:40   ` Faiyaz Mohammed
2021-06-07  8:42     ` Andy Shevchenko
2021-06-07 13:54   ` Faiyaz Mohammed
2021-06-07 16:42     ` Andy Shevchenko
2021-06-07  2:01 ` Faiyaz Mohammed
2021-06-07 10:12 ` Vlastimil Babka

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