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[[Category:UBC]]
{{UBC toc}}
This page describes proc interface of [[UBC]] subsystem.
== Old interface ==
The [[Proc/user_beancounters|Old old interface]] consisted of 2 (optionally 3) files:; <code>/proc/user_beancounters</code>: reveals an overall information about resource consumption of each beancounter in system; described [[Proc/user_beancounters|here]];; <code>/proc/user_beancounters_sub</code>: reveals information about all beancounters and sub-beancounters in system;; <code>/proc/user_beancounters_debug</code>: this files is shown shows debugging information about each beancounter. Available if <code>CONFIG_UBC_DEBUG_KMEM</code> option is turned on and shows debugging information about each beancounter. This Information revealed includes the numbers of:# objects charged from each slab;:# pages charged;:# vmalloc-ed pages;:# page beancounters;:# etc.
== New interface ==
In new interface only <code>/proc/user_beancounters</code> entry is left for compatibility with old tools. New entries reside in <code>/proc/bc</code> directory. This directory also contains subdirectories for each beancounter in the system. E.g.
<pre>
# ls /proc/bc/
=== Existing general entries ===
; <code>/proc/bc/resources</code>
: This entry looks like old <code>/proc/user_beancounters</code> entry but:# it doesn't contain “dummy” resources:# if new resource is added to BC it will appear in this entry only
; <code>/proc/bc/$BCID/resources</code>
: This entry shows the same as <code>/proc/bc/resources</code> does but for <code>$BCID</code> beancounter only.
; <code>/proc/bc/$BCID/vmaux</code>
: This entry shows auxiliary resources used in VM accounting.
; <code>/proc/bc/$BCID/kmem_debug</code>
: This entry is available with <code>CONFIG_UBC_DEBUG_KMEM</code> option set and shows per-beancounter info that was in <code>/proc/user_beancounters_debug</code> before.
=== Other entries ===
The following subsystems add their own entries in <code>/proc/bc</code> and <code>/proc/bc/$BCID</code>:
* [[IO accounting]]
=== Kernel API ===
; <code>struct bc_proc_entry;</code>
: This describes an entry that may show per-beancounter info. This looks like this:
<presource lang="c">
struct bc_proc_entry {
char *name;
struct bc_proc_entry *next;
};
</presource>
* <code>name</code> is the entry name as it will appear in <code>/proc/bc/$BCID</code>
* <code>show</code> is a callback that is to fill info about particulat beancounter
: This call registers an entry that shows per-beancounter info.
The code that fills info about BC must look like this:<presource lang="c">
static int bc_my_show(struct seq_file *f, void *v)
{
late_initcall(bc_my_init);
</presource>
{{note|Due to limitations in <code>single_open</code> the <code>struct user_beancounter</code> pointer is not passed as <code>void *v</code> into showing function but must be obtained from <code>seq_file</code> with <code>seq_beancounter</code>}}