From 18a89ba43d3e5e8a31d50838c93ec26d1cb27429 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Thu, 26 Aug 2010 10:58:19 -0700 Subject: [PATCH] Fix stack lzjb Reduce kernel stack usage by lzjb_compress() by moving uint16 array off the stack and on to the heap. The exact performance implications of this I have not measured but we absolutely need to keep stack usage to a minimum. If/when this becomes and issue we optimize. Signed-off-by: Brian Behlendorf --- module/zfs/lzjb.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/module/zfs/lzjb.c b/module/zfs/lzjb.c index ad9e423f8..4da30cf17 100644 --- a/module/zfs/lzjb.c +++ b/module/zfs/lzjb.c @@ -36,7 +36,7 @@ * source length if compression would overflow the destination buffer. */ -#include +#include #define MATCH_BITS 6 #define MATCH_MIN 3 @@ -54,12 +54,15 @@ lzjb_compress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n) int copymask = 1 << (NBBY - 1); int mlen, offset, hash; uint16_t *hp; - uint16_t lempel[LEMPEL_SIZE] = { 0 }; + uint16_t *lempel; + lempel = kmem_zalloc(LEMPEL_SIZE * sizeof (uint16_t), KM_SLEEP); while (src < (uchar_t *)s_start + s_len) { if ((copymask <<= 1) == (1 << NBBY)) { - if (dst >= (uchar_t *)d_start + d_len - 1 - 2 * NBBY) + if (dst >= (uchar_t *)d_start + d_len - 1 - 2 * NBBY) { + kmem_free(lempel, LEMPEL_SIZE*sizeof(uint16_t)); return (s_len); + } copymask = 1; copymap = dst; *dst++ = 0; @@ -89,6 +92,8 @@ lzjb_compress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n) *dst++ = *src++; } } + + kmem_free(lempel, LEMPEL_SIZE * sizeof (uint16_t)); return (dst - (uchar_t *)d_start); }