On 5/25/2021 1:23 PM, Greg KH wrote:

On Tue, May 25, 2021 at 01:08:05PM +0530, Faiyaz Mohammed wrote:

quoted

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.

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

Reported-by: kernel test robot <redacted>
Reported-by: Dan Carpenter <redacted>
Signed-off-by: Faiyaz Mohammed <redacted>
---
changes in V7:
        - Drop the older alloc_calls and free_calls interface.
changes in v6:
        - https://lore.kernel.org/linux-mm/1621341949-26762-1-git-send-email-faiyazm@codeaurora.org/ (local)

changes in v5:
        - https://lore.kernel.org/linux-mm/1620296523-21922-1-git-send-email-faiyazm@codeaurora.org/ (local)

changes in v4:
        - https://lore.kernel.org/linux-mm/1618583239-18124-1-git-send-email-faiyazm@codeaurora.org/ (local)

changes in v3:
        - https://lore.kernel.org/linux-mm/1617712064-12264-1-git-send-email-faiyazm@codeaurora.org/ (local)

changes in v2:
        - https://lore.kernel.org/linux-mm/3ac1d3e6-6207-96ad-16a1-0f5139d8b2b5@codeaurora.org/ (local)

changes in v1:
        - https://lore.kernel.org/linux-mm/1610443287-23933-1-git-send-email-faiyazm@codeaurora.org/ (local)

 include/linux/slub_def.h |   8 ++
 mm/slab_common.c         |   9 ++
 mm/slub.c                | 353 ++++++++++++++++++++++++++++++++++-------------
 3 files changed, 276 insertions(+), 94 deletions(-)

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index dcde82a..b413ebe 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h

@@ -159,6 +159,14 @@ static inline void sysfs_slab_release(struct kmem_cache *s)
 }
 #endif
 
+#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
+#define SLAB_SUPPORTS_DEBUGFS
+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 a4a5714..873dd79 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c

@@ -455,6 +455,9 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
 #else
 		slab_kmem_cache_release(s);
 #endif
+#ifdef SLAB_SUPPORTS_DEBUGFS
+		debugfs_slab_release(s);
+#endif

Why do you need these #ifdef if your slub_dev.h file already provides an
"empty" function for this?

We are not including slub_def.h directly. mm/slab.h includes the
slub_def.h if CONFIG_SLUB enable,

from mm/slab.h
#ifdef CONFIG_SLAB
#include <linux/slab_def.h>
#endif

#ifdef CONFIG_SLUB
#include <linux/slub_def.h>
#endif

so if CONFIG_SLAB is enable then mm/slab.h includes slab_def.h, to avoid
undefined reference error added SLAB_SUPPORTS_DEBUGFS like
SLAB_SUPPORTS_SYSFS.

quoted

 	}
 }
 

@@ -472,6 +475,9 @@ static int shutdown_cache(struct kmem_cache *s)
 #ifdef SLAB_SUPPORTS_SYSFS
 		sysfs_slab_unlink(s);
 #endif
+#ifdef SLAB_SUPPORTS_DEBUGFS
+		debugfs_slab_release(s);
+#endif

Same here.

quoted

 		list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
 		schedule_work(&slab_caches_to_rcu_destroy_work);
 	} else {

@@ -482,6 +488,9 @@ static int shutdown_cache(struct kmem_cache *s)
 #else
 		slab_kmem_cache_release(s);
 #endif
+#ifdef SLAB_SUPPORTS_DEBUGFS
+		debugfs_slab_release(s);
+#endif

And here.

What is wrong with your .h file that keeps the need for #ifdef in the .c
file?

I thought I've asked about this a number of times in the past, what am I
missing?

thanks,

greg k-h