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md/raid456: distribute raid processing over multiple cores 

Now that the resources to handle stripe_head operations are allocated
percpu it is possible for raid5d to distribute stripe handling over
multiple cores.  This conversion also adds a call to cond_resched() in
the non-multicore case to prevent one core from getting monopolized for
raid operations.

Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2009-08-29 19:13:13 -07:00
parent b774ef491b
commit 07a3b417dc
2 changed files with 45 additions and 2 deletions
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11
drivers/md/Kconfig
View File

@ -154,6 +154,17 @@ config MD_RAID456
If unsure, say Y.
config MULTICORE_RAID456
bool "RAID-4/RAID-5/RAID-6 Multicore processing (EXPERIMENTAL)"
depends on MD_RAID456
depends on SMP
depends on EXPERIMENTAL
---help---
Enable the raid456 module to dispatch per-stripe raid operations to a
thread pool.
If unsure, say N.
config MD_RAID6_PQ
tristate

36
drivers/md/raid5.c
View File

@ -47,6 +47,7 @@
#include <linux/kthread.h>
#include <linux/raid/pq.h>
#include <linux/async_tx.h>
#include <linux/async.h>
#include <linux/seq_file.h>
#include <linux/cpu.h>
#include "md.h"
@ -4314,6 +4315,36 @@ static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
return handled;
}
#ifdef CONFIG_MULTICORE_RAID456
static void __process_stripe(void *param, async_cookie_t cookie)
{
struct stripe_head *sh = param;
handle_stripe(sh);
release_stripe(sh);
}
static void process_stripe(struct stripe_head *sh, struct list_head *domain)
{
async_schedule_domain(__process_stripe, sh, domain);
}
static void synchronize_stripe_processing(struct list_head *domain)
{
async_synchronize_full_domain(domain);
}
#else
static void process_stripe(struct stripe_head *sh, struct list_head *domain)
{
handle_stripe(sh);
release_stripe(sh);
cond_resched();
}
static void synchronize_stripe_processing(struct list_head *domain)
{
}
#endif
/*
@ -4328,6 +4359,7 @@ static void raid5d(mddev_t *mddev)
struct stripe_head *sh;
raid5_conf_t *conf = mddev_to_conf(mddev);
int handled;
LIST_HEAD(raid_domain);
pr_debug("+++ raid5d active\n");
@ -4364,8 +4396,7 @@ static void raid5d(mddev_t *mddev)
spin_unlock_irq(&conf->device_lock);
handled++;
handle_stripe(sh);
release_stripe(sh);
process_stripe(sh, &raid_domain);
spin_lock_irq(&conf->device_lock);
}
@ -4373,6 +4404,7 @@ static void raid5d(mddev_t *mddev)
spin_unlock_irq(&conf->device_lock);
synchronize_stripe_processing(&raid_domain);
async_tx_issue_pending_all();
unplug_slaves(mddev);