On August 22, 2016 8:22:57 PM PDT, liuzhengy...@kylinos.cn wrote: > >To test and choose an best algorithm for raid6, disk number >and disk data must be offered. Those input depend on page >size and gfmul table at current time. It would lead the disk >number less than 4 when the page size is more than 64KB.This >patch would support arbitrarily page size by defining a macro >for disk number and using random number to fill with disk data. > >Signed-off-by: ZhengYuan Liu <liuzhengy...@kylinos.cn> >--- > lib/raid6/algos.c | 36 ++++++++++++++++++++++-------------- > 1 file changed, 22 insertions(+), 14 deletions(-) > >diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c >index 975c6e0..f15a4d2 100644 >--- a/lib/raid6/algos.c >+++ b/lib/raid6/algos.c >@@ -23,6 +23,7 @@ > #else > #include <linux/module.h> > #include <linux/gfp.h> >+#include <linux/random.h> > #if !RAID6_USE_EMPTY_ZERO_PAGE > /* In .bss so it's zeroed */ >const char raid6_empty_zero_page[PAGE_SIZE] >__attribute__((aligned(256))); >@@ -30,6 +31,8 @@ EXPORT_SYMBOL(raid6_empty_zero_page); > #endif > #endif > >+#define RAID6_DISKS 8 >+ > struct raid6_calls raid6_call; > EXPORT_SYMBOL_GPL(raid6_call); > >@@ -129,7 +132,7 @@ static inline const struct raid6_recov_calls >*raid6_choose_recov(void) > } > > static inline const struct raid6_calls *raid6_choose_gen( >- void *(*const dptrs)[(65536/PAGE_SIZE)+2], const int disks) >+ void *(*const dptrs)[RAID6_DISKS], const int disks) > { > unsigned long perf, bestgenperf, bestxorperf, j0, j1; > int start = (disks>>1)-1, stop = disks-3; /* work on the second > half >of the disks */ >@@ -206,27 +209,32 @@ static inline const struct raid6_calls >*raid6_choose_gen( > > int __init raid6_select_algo(void) > { >- const int disks = (65536/PAGE_SIZE)+2; >+ const int disks = RAID6_DISKS; > > 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; >+ char *disk_ptr; >+ void *dptrs[RAID6_DISKS]; >+ int i, j; > >- /* Normal code - use a 2-page allocation to avoid D$ conflict */ >- syndromes = (void *) __get_free_pages(GFP_KERNEL, 1); >+ /* use a 8-page allocation, The first 6 pages for disks >+ and the last 2 pages for syndromes */ >+ disk_ptr = (void *) __get_free_pages(GFP_KERNEL, 3); > >- if (!syndromes) { >+ if (!disk_ptr) { > pr_err("raid6: Yikes! No memory available.\n"); > return -ENOMEM; > } > >- dptrs[disks-2] = syndromes; >- dptrs[disks-1] = syndromes + PAGE_SIZE; >+ /* Fix-me: may should use get_random_bytes_arch() instead of >get_random_bytes() */ >+ for (i = 0; i < disks-2; i++) { >+ dptrs[i] = disk_ptr + PAGE_SIZE*i; >+ for (j = 0; j < PAGE_SIZE; j++) >+ get_random_bytes(dptrs[i]+j, 1); >+ } >+ >+ dptrs[disks-2] = disk_ptr + PAGE_SIZE*(disks-2); >+ dptrs[disks-1] = disk_ptr + PAGE_SIZE*(disks-1); > > /* select raid gen_syndrome function */ > gen_best = raid6_choose_gen(&dptrs, disks); >@@ -234,7 +242,7 @@ int __init raid6_select_algo(void) > /* select raid recover functions */ > rec_best = raid6_choose_recov(); > >- free_pages((unsigned long)syndromes, 1); >+ free_pages((unsigned long)disk_ptr, 3); > > return gen_best && rec_best ? 0 : -EINVAL; > }
Do you have any idea how long this takes to run? People are already complaining about the boot time penalty. get_random_*() is quite expensive and is overkill... -- Sent from my Android device with K-9 Mail. Please excuse brevity and formatting.