6f6b5d1ec5
This patch changes percpu_ida_alloc() + callers to accept task state
bitmask for prepare_to_wait() for code like target/iscsi that needs
it for interruptible sleep, that is provided in a subsequent patch.
It now expects TASK_UNINTERRUPTIBLE when the caller is able to sleep
waiting for a new tag, or TASK_RUNNING when the caller cannot sleep,
and is forced to return a negative value when no tags are available.
v2 changes:
- Include blk-mq + tcm_fc + vhost/scsi + target/iscsi changes
- Drop signal_pending_state() call
v3 changes:
- Only call prepare_to_wait() + finish_wait() when != TASK_RUNNING
(PeterZ)
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: <stable@vger.kernel.org> #3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
82 lines
2.3 KiB
C
82 lines
2.3 KiB
C
#ifndef __PERCPU_IDA_H__
|
|
#define __PERCPU_IDA_H__
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/init.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/spinlock_types.h>
|
|
#include <linux/wait.h>
|
|
#include <linux/cpumask.h>
|
|
|
|
struct percpu_ida_cpu;
|
|
|
|
struct percpu_ida {
|
|
/*
|
|
* number of tags available to be allocated, as passed to
|
|
* percpu_ida_init()
|
|
*/
|
|
unsigned nr_tags;
|
|
unsigned percpu_max_size;
|
|
unsigned percpu_batch_size;
|
|
|
|
struct percpu_ida_cpu __percpu *tag_cpu;
|
|
|
|
/*
|
|
* Bitmap of cpus that (may) have tags on their percpu freelists:
|
|
* steal_tags() uses this to decide when to steal tags, and which cpus
|
|
* to try stealing from.
|
|
*
|
|
* It's ok for a freelist to be empty when its bit is set - steal_tags()
|
|
* will just keep looking - but the bitmap _must_ be set whenever a
|
|
* percpu freelist does have tags.
|
|
*/
|
|
cpumask_t cpus_have_tags;
|
|
|
|
struct {
|
|
spinlock_t lock;
|
|
/*
|
|
* When we go to steal tags from another cpu (see steal_tags()),
|
|
* we want to pick a cpu at random. Cycling through them every
|
|
* time we steal is a bit easier and more or less equivalent:
|
|
*/
|
|
unsigned cpu_last_stolen;
|
|
|
|
/* For sleeping on allocation failure */
|
|
wait_queue_head_t wait;
|
|
|
|
/*
|
|
* Global freelist - it's a stack where nr_free points to the
|
|
* top
|
|
*/
|
|
unsigned nr_free;
|
|
unsigned *freelist;
|
|
} ____cacheline_aligned_in_smp;
|
|
};
|
|
|
|
/*
|
|
* Number of tags we move between the percpu freelist and the global freelist at
|
|
* a time
|
|
*/
|
|
#define IDA_DEFAULT_PCPU_BATCH_MOVE 32U
|
|
/* Max size of percpu freelist, */
|
|
#define IDA_DEFAULT_PCPU_SIZE ((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2)
|
|
|
|
int percpu_ida_alloc(struct percpu_ida *pool, int state);
|
|
void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
|
|
|
|
void percpu_ida_destroy(struct percpu_ida *pool);
|
|
int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
|
|
unsigned long max_size, unsigned long batch_size);
|
|
static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags)
|
|
{
|
|
return __percpu_ida_init(pool, nr_tags, IDA_DEFAULT_PCPU_SIZE,
|
|
IDA_DEFAULT_PCPU_BATCH_MOVE);
|
|
}
|
|
|
|
typedef int (*percpu_ida_cb)(unsigned, void *);
|
|
int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
|
|
void *data);
|
|
|
|
unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu);
|
|
#endif /* __PERCPU_IDA_H__ */
|