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lib/raid6: cleanup gen_syndrome function selection

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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: Jim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
Jim Kukunas 2012-05-22 13:54:24 +10:00 committed by NeilBrown
parent 2dbf708448
commit 96e67703e7
1 changed files with 57 additions and 47 deletions
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104
lib/raid6/algos.c
View file

@ -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;
@ -103,62 +103,38 @@ 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");
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)
static inline const struct raid6_calls *raid6_choose_gen(
void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks)
{
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;
unsigned long perf, bestperf, j0, j1;
const struct raid6_calls *const *algo;
const struct raid6_calls *best;
disks = (65536/PAGE_SIZE)+2;
for ( i = 0 ; i < disks-2 ; i++ ) {
dptrs[i] = ((char *)raid6_gfmul) + PAGE_SIZE*i;
}
for (bestperf = 0, best = NULL, algo = raid6_algos; *algo; algo++) {
if (!best || (*algo)->prefer >= best->prefer) {
if ((*algo)->valid && !(*algo)->valid())
continue;
/* 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 ( algo = raid6_algos ; *algo ; algo++ ) {
if ( !(*algo)->valid || (*algo)->valid() ) {
perf = 0;
preempt_disable();
j0 = jiffies;
while ( (j1 = jiffies) == j0 )
while ((j1 = jiffies) == j0)
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();
return best ? 0 : -EINVAL;
free_pages((unsigned long)syndromes, 1);
return gen_best && rec_best ? 0 : -EINVAL;
}
static void raid6_exit(void)