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block: split softirq handling into blk-softirq.c

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Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2008-07-28 13:06:00 +02:00
parent 0835da67c1
commit b646fc59b3
3 changed files with 105 additions and 90 deletions
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4
block/Makefile
View file

@ -4,8 +4,8 @@
obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \
blk-barrier.o blk-settings.o blk-ioc.o blk-map.o \
blk-exec.o blk-merge.o ioctl.o genhd.o scsi_ioctl.o \
cmd-filter.o
blk-exec.o blk-merge.o blk-softirq.o ioctl.o genhd.o \
scsi_ioctl.o cmd-filter.o
obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o

88
block/blk-core.c
View file

@ -26,8 +26,6 @@
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/blktrace_api.h>
#include <linux/fault-inject.h>
@ -50,8 +48,6 @@ struct kmem_cache *blk_requestq_cachep;
*/
static struct workqueue_struct *kblockd_workqueue;
static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
static void drive_stat_acct(struct request *rq, int new_io)
{
struct hd_struct *part;
@ -1643,82 +1639,6 @@ static int __end_that_request_first(struct request *req, int error,
return 1;
}
/*
* splice the completion data to a local structure and hand off to
* process_completion_queue() to complete the requests
*/
static void blk_done_softirq(struct softirq_action *h)
{
struct list_head *cpu_list, local_list;
local_irq_disable();
cpu_list = &__get_cpu_var(blk_cpu_done);
list_replace_init(cpu_list, &local_list);
local_irq_enable();
while (!list_empty(&local_list)) {
struct request *rq;
rq = list_entry(local_list.next, struct request, donelist);
list_del_init(&rq->donelist);
rq->q->softirq_done_fn(rq);
}
}
static int __cpuinit blk_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
/*
* If a CPU goes away, splice its entries to the current CPU
* and trigger a run of the softirq
*/
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
int cpu = (unsigned long) hcpu;
local_irq_disable();
list_splice_init(&per_cpu(blk_cpu_done, cpu),
&__get_cpu_var(blk_cpu_done));
raise_softirq_irqoff(BLOCK_SOFTIRQ);
local_irq_enable();
}
return NOTIFY_OK;
}
static struct notifier_block blk_cpu_notifier __cpuinitdata = {
.notifier_call = blk_cpu_notify,
};
/**
* blk_complete_request - end I/O on a request
* @req: the request being processed
*
* Description:
* Ends all I/O on a request. It does not handle partial completions,
* unless the driver actually implements this in its completion callback
* through requeueing. The actual completion happens out-of-order,
* through a softirq handler. The user must have registered a completion
* callback through blk_queue_softirq_done().
**/
void blk_complete_request(struct request *req)
{
struct list_head *cpu_list;
unsigned long flags;
BUG_ON(!req->q->softirq_done_fn);
local_irq_save(flags);
cpu_list = &__get_cpu_var(blk_cpu_done);
list_add_tail(&req->donelist, cpu_list);
raise_softirq_irqoff(BLOCK_SOFTIRQ);
local_irq_restore(flags);
}
EXPORT_SYMBOL(blk_complete_request);
/*
* queue lock must be held
*/
@ -2053,8 +1973,6 @@ EXPORT_SYMBOL(kblockd_flush_work);
int __init blk_dev_init(void)
{
int i;
kblockd_workqueue = create_workqueue("kblockd");
if (!kblockd_workqueue)
panic("Failed to create kblockd\n");
@ -2065,12 +1983,6 @@ int __init blk_dev_init(void)
blk_requestq_cachep = kmem_cache_create("blkdev_queue",
sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
for_each_possible_cpu(i)
INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
register_hotcpu_notifier(&blk_cpu_notifier);
return 0;
}

103
block/blk-softirq.c Normal file
View file

@ -0,0 +1,103 @@
/*
* Functions related to softirq rq completions
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include "blk.h"
static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
static int __cpuinit blk_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
/*
* If a CPU goes away, splice its entries to the current CPU
* and trigger a run of the softirq
*/
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
int cpu = (unsigned long) hcpu;
local_irq_disable();
list_splice_init(&per_cpu(blk_cpu_done, cpu),
&__get_cpu_var(blk_cpu_done));
raise_softirq_irqoff(BLOCK_SOFTIRQ);
local_irq_enable();
}
return NOTIFY_OK;
}
static struct notifier_block blk_cpu_notifier __cpuinitdata = {
.notifier_call = blk_cpu_notify,
};
/*
* splice the completion data to a local structure and hand off to
* process_completion_queue() to complete the requests
*/
static void blk_done_softirq(struct softirq_action *h)
{
struct list_head *cpu_list, local_list;
local_irq_disable();
cpu_list = &__get_cpu_var(blk_cpu_done);
list_replace_init(cpu_list, &local_list);
local_irq_enable();
while (!list_empty(&local_list)) {
struct request *rq;
rq = list_entry(local_list.next, struct request, donelist);
list_del_init(&rq->donelist);
rq->q->softirq_done_fn(rq);
}
}
/**
* blk_complete_request - end I/O on a request
* @req: the request being processed
*
* Description:
* Ends all I/O on a request. It does not handle partial completions,
* unless the driver actually implements this in its completion callback
* through requeueing. The actual completion happens out-of-order,
* through a softirq handler. The user must have registered a completion
* callback through blk_queue_softirq_done().
**/
void blk_complete_request(struct request *req)
{
struct list_head *cpu_list;
unsigned long flags;
BUG_ON(!req->q->softirq_done_fn);
local_irq_save(flags);
cpu_list = &__get_cpu_var(blk_cpu_done);
list_add_tail(&req->donelist, cpu_list);
raise_softirq_irqoff(BLOCK_SOFTIRQ);
local_irq_restore(flags);
}
EXPORT_SYMBOL(blk_complete_request);
int __init blk_softirq_init(void)
{
int i;
for_each_possible_cpu(i)
INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
register_hotcpu_notifier(&blk_cpu_notifier);
return 0;
}
subsys_initcall(blk_softirq_init);