Merge branch 'slab/for-6.1/slub_debug_waste' into slab/for-next

A patch from Feng Tang that enhances the existing debugfs alloc_traces
file for kmalloc caches with information about how much space is wasted
by allocations that needs less space than the particular kmalloc cache
provides.

Author: tehcaster

Documentation/mm/slub.rst

@@ -400,21 +400,30 @@ information:
     allocated objects. The output is sorted by frequency of each trace.
 
     Information in the output:
-    Number of objects, allocating function, minimal/average/maximal jiffies since alloc,
-    pid range of the allocating processes, cpu mask of allocating cpus, and stack trace.
+    Number of objects, allocating function, possible memory wastage of
+    kmalloc objects(total/per-object), minimal/average/maximal jiffies
+    since alloc, pid range of the allocating processes, cpu mask of
+    allocating cpus, numa node mask of origins of memory, and stack trace.
 
     Example:::
 
-    1085 populate_error_injection_list+0x97/0x110 age=166678/166680/166682 pid=1 cpus=1::
-	__slab_alloc+0x6d/0x90
-	kmem_cache_alloc_trace+0x2eb/0x300
-	populate_error_injection_list+0x97/0x110
-	init_error_injection+0x1b/0x71
-	do_one_initcall+0x5f/0x2d0
-	kernel_init_freeable+0x26f/0x2d7
-	kernel_init+0xe/0x118
-	ret_from_fork+0x22/0x30
-
+    338 pci_alloc_dev+0x2c/0xa0 waste=521872/1544 age=290837/291891/293509 pid=1 cpus=106 nodes=0-1
+        __kmem_cache_alloc_node+0x11f/0x4e0
+        kmalloc_trace+0x26/0xa0
+        pci_alloc_dev+0x2c/0xa0
+        pci_scan_single_device+0xd2/0x150
+        pci_scan_slot+0xf7/0x2d0
+        pci_scan_child_bus_extend+0x4e/0x360
+        acpi_pci_root_create+0x32e/0x3b0
+        pci_acpi_scan_root+0x2b9/0x2d0
+        acpi_pci_root_add.cold.11+0x110/0xb0a
+        acpi_bus_attach+0x262/0x3f0
+        device_for_each_child+0xb7/0x110
+        acpi_dev_for_each_child+0x77/0xa0
+        acpi_bus_attach+0x108/0x3f0
+        device_for_each_child+0xb7/0x110
+        acpi_dev_for_each_child+0x77/0xa0
+        acpi_bus_attach+0x108/0x3f0
 
 2. free_traces::
 

include/linux/slab.h

@@ -29,6 +29,8 @@
 #define SLAB_RED_ZONE		((slab_flags_t __force)0x00000400U)
 /* DEBUG: Poison objects */
 #define SLAB_POISON		((slab_flags_t __force)0x00000800U)
+/* Indicate a kmalloc slab */
+#define SLAB_KMALLOC		((slab_flags_t __force)0x00001000U)
 /* Align objs on cache lines */
 #define SLAB_HWCACHE_ALIGN	((slab_flags_t __force)0x00002000U)
 /* Use GFP_DMA memory */

mm/slab_common.c

@@ -661,7 +661,8 @@ struct kmem_cache *__init create_kmalloc_cache(const char *name,
 	if (!s)
 		panic("Out of memory when creating slab %s\n", name);
 
-	create_boot_cache(s, name, size, flags, useroffset, usersize);
+	create_boot_cache(s, name, size, flags | SLAB_KMALLOC, useroffset,
+								usersize);
 	kasan_cache_create_kmalloc(s);
 	list_add(&s->list, &slab_caches);
 	s->refcount = 1;