BC proc entries
This page describes proc interface of UBC subsystem.
Contents
Old interface
Old interface consisted of 2 (optionally 3) files
user_beancounters
- reveals an overall information about resource consumption of each beancounter in system
user_beancounters_sub
- reveals information about all beancounters and sub-beancounters in system
user_beancounters_debug
- this files is shown if
CONFIG_UBC_DEBUG_KMEM
option is turned on and shows debugging information about each beancounter. This includes the numbers of
- objects charged from each slab
- pages charged
- vmalloc-ed pages
- page beancounters
- etc
New interface
In new interface only user_beancounters
entry is left for compatibility with old tools. New entries reside in /proc/bc
directory. This directory also contains subdirectories for each beancounter in the system. E.g.
# ls /proc/bc/ 0 ioacct_debug resources # vzctl start 101 ... # ls /proc/bc 0 101 ioacct_debug resources # ls /proc/bc/101/ ioacct kmem_debug resources vmaux
All new entries that are in /proc/bc
shows some overall information about BC subsystem, while entries in /proc/bc/$BCID
show per-beancounter info.
Existing general entries
/proc/bc/resources
- This entry looks like old
user_beancounters
entry but
- it doesn't contain “dummy” resources
- if new resource is added to BC it will appear in this entry only
/proc/bc/$BCID/resources
- This entry shows the same as
bc/resources
does but for$BCID
beancounter only. /proc/bc/$BCID/vmaux
- This entry shows auxiliary resources used in VM accounting.
/proc/bc/$BCID/kmem_debug
- This entry is available with
CONFIG_UBC_DEBUG_KMEM
option set and shows per-beancounter info that was in/proc/user_beancounters_debug
before.
Other entries
The following subsystems add their own entries in /proc/bc
and /proc/bc/$BCID
Kernel API
Subsystems may add its own entries in /proc/bc
or /proc/bc/$BCID
. To facilitate this the following API is used in BC sybsystem (declared in include/ub/proc.h
).
struct proc_dir_entry *bc_proc_root
- This is an entry that corresponds to
/proc/bc
directory. If a subsystem wishes to report some information that is not per-beancounter it may create entry using this as a parent. struct bc_proc_entry;
- This describes an entry that may show per-beancounter info. This looks like this:
struct bc_proc_entry { char *name; int (*show)(struct seq_file *, void *); struct bc_proc_entry *next; };
name
is the entry name as it will appear in/proc/bc/$BCID
show
is a callback that is to fill info about particulat beancounter
void bc_register_proc_entry(struct bc_proc_entry *);
- This call registers an entry that shows per-beancounter info.
The code that fills info about BC must look like this
static int bc_my_show(struct seq_file *f, void *v) { struct user_beancounter *ub; ub = seq_beancounter(f); /* dump info into f here */ return 0; } ... static struct bc_proc_entry my_entry = { .name = "my_entry", .show = bc_my_show, }; static int __init bc_my_init(void) { bc_register_proc_entry(&my_entry); return 0; } late_initcall(bc_my_init);
Note: Due to limitations in single_open the struct user_beancounter pointer is not passed as void *v into showing function but must be obtained from seq_file with seq_beancounter
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