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Commit 07a3b417 authored by Dan Williams's avatar Dan Williams
Browse files

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: default avatarDan Williams <dan.j.williams@intel.com>
parent b774ef49

drivers/md/Kconfig

+11 −0
Original line number Original line Diff line number Diff line
@@ -154,6 +154,17 @@ config MD_RAID456 




	  If unsure, say Y.

	  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

config MD_RAID6_PQ

	tristate

	tristate

drivers/md/raid5.c

+34 −2
Original line number Original line Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <linux/kthread.h>

#include <linux/kthread.h>

#include <linux/raid/pq.h>

#include <linux/raid/pq.h>

#include <linux/async_tx.h>

#include <linux/async_tx.h>

#include <linux/async.h>

#include <linux/seq_file.h>

#include <linux/seq_file.h>

#include <linux/cpu.h>

#include <linux/cpu.h>

#include "md.h"

#include "md.h"
@@ -4314,6 +4315,36 @@ static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) 
	return handled;

	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;

	struct stripe_head *sh;

	raid5_conf_t *conf = mddev_to_conf(mddev);

	raid5_conf_t *conf = mddev_to_conf(mddev);

	int handled;

	int handled;

	LIST_HEAD(raid_domain);





	pr_debug("+++ raid5d active\n");

	pr_debug("+++ raid5d active\n");
@@ -4364,8 +4396,7 @@ static void raid5d(mddev_t *mddev) 
		spin_unlock_irq(&conf->device_lock);

		spin_unlock_irq(&conf->device_lock);

		

		

		handled++;

		handled++;

		handle_stripe(sh);

		process_stripe(sh, &raid_domain);

		release_stripe(sh);





		spin_lock_irq(&conf->device_lock);

		spin_lock_irq(&conf->device_lock);

	}

	}
@@ -4373,6 +4404,7 @@ static void raid5d(mddev_t *mddev) 




	spin_unlock_irq(&conf->device_lock);

	spin_unlock_irq(&conf->device_lock);





	synchronize_stripe_processing(&raid_domain);

	async_tx_issue_pending_all();

	async_tx_issue_pending_all();

	unplug_slaves(mddev);

	unplug_slaves(mddev);