Commit 96e67703 authored by Jim Kukunas's avatar Jim Kukunas Committed by NeilBrown
Browse files

lib/raid6: cleanup gen_syndrome function selection 



Reorders functions in raid6_algos as well as the preference check
to reduce the number of functions tested on initialization.

Also, creates symmetry between choosing the gen_syndrome functions
and choosing the recovery functions.

Signed-off-by: default avatarJim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 2dbf7084

lib/raid6/algos.c

+57 −47
Original line number Diff line number Diff line
@@ -34,10 +34,6 @@ struct raid6_calls raid6_call; 
EXPORT_SYMBOL_GPL(raid6_call);



const struct raid6_calls * const raid6_algos[] = {

	&raid6_intx1,

	&raid6_intx2,

	&raid6_intx4,

	&raid6_intx8,

#if defined(__ia64__)

	&raid6_intx16,

	&raid6_intx32,
@@ -61,6 +57,10 @@ const struct raid6_calls * const raid6_algos[] = { 
	&raid6_altivec4,

	&raid6_altivec8,

#endif

	&raid6_intx1,

	&raid6_intx2,

	&raid6_intx4,

	&raid6_intx8,

	NULL

};
@@ -86,7 +86,7 @@ const struct raid6_recov_calls *const raid6_recov_algos[] = { 
#define time_before(x, y) ((x) < (y))

#endif



static inline void raid6_choose_recov(void)

static inline const struct raid6_recov_calls *raid6_choose_recov(void)

{

	const struct raid6_recov_calls *const *algo;

	const struct raid6_recov_calls *best;
@@ -103,43 +103,22 @@ static inline void raid6_choose_recov(void) 
		printk("raid6: using %s recovery algorithm\n", best->name);

	} else

		printk("raid6: Yikes! No recovery algorithm found!\n");

}





/* Try to pick the best algorithm */

/* This code uses the gfmul table as convenient data set to abuse */

	return best;

}



int __init raid6_select_algo(void)

static inline const struct raid6_calls *raid6_choose_gen(

	void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks)

{

	unsigned long perf, bestperf, j0, j1;

	const struct raid6_calls *const *algo;

	const struct raid6_calls *best;

	char *syndromes;

	void *dptrs[(65536/PAGE_SIZE)+2];

	int i, disks;

	unsigned long perf, bestperf;

	int bestprefer;

	unsigned long j0, j1;



	disks = (65536/PAGE_SIZE)+2;

	for ( i = 0 ; i < disks-2 ; i++ ) {

		dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i;

	}



	/* Normal code - use a 2-page allocation to avoid D$ conflict */

	syndromes = (void *) __get_free_pages(GFP_KERNEL, 1);



	if ( !syndromes ) {

		printk("raid6: Yikes!  No memory available.\n");

		return -ENOMEM;

	}



	dptrs[disks-2] = syndromes;

	dptrs[disks-1] = syndromes + PAGE_SIZE;



	bestperf = 0;  bestprefer = 0;  best = NULL;

	for (bestperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {

		if (!best || (*algo)->prefer >= best->prefer) {

			if ((*algo)->valid && !(*algo)->valid())

				continue;



	for ( algo = raid6_algos ; *algo ; algo++ ) {

		if ( !(*algo)->valid || (*algo)->valid() ) {

			perf = 0;



			preempt_disable();
@@ -148,17 +127,14 @@ int __init raid6_select_algo(void) 
				cpu_relax();

			while (time_before(jiffies,

					    j1 + (1<<RAID6_TIME_JIFFIES_LG2))) {

				(*algo)->gen_syndrome(disks, PAGE_SIZE, dptrs);

				(*algo)->gen_syndrome(disks, PAGE_SIZE, *dptrs);

				perf++;

			}

			preempt_enable();



			if ( (*algo)->prefer > bestprefer ||

			     ((*algo)->prefer == bestprefer &&

			      perf > bestperf) ) {

				best = *algo;

				bestprefer = best->prefer;

			if (perf > bestperf) {

				bestperf = perf;

				best = *algo;

			}

			printk("raid6: %-8s %5ld MB/s\n", (*algo)->name,

			       (perf*HZ) >> (20-16+RAID6_TIME_JIFFIES_LG2));
@@ -173,12 +149,46 @@ int __init raid6_select_algo(void) 
	} else

		printk("raid6: Yikes!  No algorithm found!\n");



	free_pages((unsigned long)syndromes, 1);

	return best;

}





/* Try to pick the best algorithm */

/* This code uses the gfmul table as convenient data set to abuse */



int __init raid6_select_algo(void)

{

	const int disks = (65536/PAGE_SIZE)+2;



	const struct raid6_calls *gen_best;

	const struct raid6_recov_calls *rec_best;

	char *syndromes;

	void *dptrs[(65536/PAGE_SIZE)+2];

	int i;



	for (i = 0; i < disks-2; i++)

		dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i;



	/* Normal code - use a 2-page allocation to avoid D$ conflict */

	syndromes = (void *) __get_free_pages(GFP_KERNEL, 1);



	if (!syndromes) {

		printk("raid6: Yikes!  No memory available.\n");

		return -ENOMEM;

	}



	dptrs[disks-2] = syndromes;

	dptrs[disks-1] = syndromes + PAGE_SIZE;



	/* select raid gen_syndrome function */

	gen_best = raid6_choose_gen(&dptrs, disks);



	/* select raid recover functions */

	raid6_choose_recov();

	rec_best = raid6_choose_recov();



	free_pages((unsigned long)syndromes, 1);



	return best ? 0 : -EINVAL;

	return gen_best && rec_best ? 0 : -EINVAL;

}



static void raid6_exit(void)

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