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authorOliver Glitta <glittao@gmail.com>2021-06-08 11:45:17 +0300
committerVlastimil Babka <vbabka@suse.cz>2022-04-06 12:09:48 +0300
commit9f04b55f003ccd00cf5e47bfb4116457f591d6de (patch)
tree2684d541efcdd4aacbc2c3b24f868a2ed9a9c8d2 /Documentation/vm
parent553c0369b3e132b4c1081700029f6d9e1a7332cf (diff)
downloadlinux-9f04b55f003ccd00cf5e47bfb4116457f591d6de.tar.xz
slab, documentation: add description of debugfs files for SLUB caches
Add description of debugfs files alloc_traces and free_traces to SLUB cache documentation. [ vbabka@suse.cz: some rewording ] Signed-off-by: Oliver Glitta <glittao@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: linux-doc@vger.kernel.org Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: David Rientjes <rientjes@google.com>
Diffstat (limited to 'Documentation/vm')
-rw-r--r--Documentation/vm/slub.rst64
1 files changed, 64 insertions, 0 deletions
diff --git a/Documentation/vm/slub.rst b/Documentation/vm/slub.rst
index d3028554b1e9..43063ade737a 100644
--- a/Documentation/vm/slub.rst
+++ b/Documentation/vm/slub.rst
@@ -384,5 +384,69 @@ 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, minimal/average/maximal jiffies since alloc,
+ pid range of the allocating processes, cpu mask of allocating cpus, 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
+
+
+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