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-rw-r--r--Documentation/mm/slub.rst (renamed from Documentation/vm/slub.rst)73
1 files changed, 73 insertions, 0 deletions
diff --git a/Documentation/vm/slub.rst b/Documentation/mm/slub.rst
index d3028554b1e9..4e1578186b4f 100644
--- a/Documentation/vm/slub.rst
+++ b/Documentation/mm/slub.rst
@@ -384,5 +384,78 @@ c) Execute ``slabinfo-gnuplot.sh`` in '-t' mode, passing all of the
40,60`` range will plot only samples collected between 40th and
60th seconds).
+
+DebugFS files for SLUB
+======================
+
+For more information about current state of SLUB caches with the user tracking
+debug option enabled, debugfs files are available, typically under
+/sys/kernel/debug/slab/<cache>/ (created only for caches with enabled user
+tracking). There are 2 types of these files with the following debug
+information:
+
+1. alloc_traces::
+
+ Prints information about unique allocation traces of the currently
+ allocated objects. The output is sorted by frequency of each trace.
+
+ Information in the output:
+ 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:::
+
+ 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::
+
+ Prints information about unique freeing traces of the currently allocated
+ objects. The freeing traces thus come from the previous life-cycle of the
+ objects and are reported as not available for objects allocated for the first
+ time. The output is sorted by frequency of each trace.
+
+ Information in the output:
+ Number of objects, freeing function, minimal/average/maximal jiffies since free,
+ pid range of the freeing processes, cpu mask of freeing cpus, and stack trace.
+
+ Example:::
+
+ 1980 <not-available> age=4294912290 pid=0 cpus=0
+ 51 acpi_ut_update_ref_count+0x6a6/0x782 age=236886/237027/237772 pid=1 cpus=1
+ kfree+0x2db/0x420
+ acpi_ut_update_ref_count+0x6a6/0x782
+ acpi_ut_update_object_reference+0x1ad/0x234
+ acpi_ut_remove_reference+0x7d/0x84
+ acpi_rs_get_prt_method_data+0x97/0xd6
+ acpi_get_irq_routing_table+0x82/0xc4
+ acpi_pci_irq_find_prt_entry+0x8e/0x2e0
+ acpi_pci_irq_lookup+0x3a/0x1e0
+ acpi_pci_irq_enable+0x77/0x240
+ pcibios_enable_device+0x39/0x40
+ do_pci_enable_device.part.0+0x5d/0xe0
+ pci_enable_device_flags+0xfc/0x120
+ pci_enable_device+0x13/0x20
+ virtio_pci_probe+0x9e/0x170
+ local_pci_probe+0x48/0x80
+ pci_device_probe+0x105/0x1c0
+
Christoph Lameter, May 30, 2007
Sergey Senozhatsky, October 23, 2015