The patch titled Subject: string: memchr_inv() speed improvements has been removed from the -mm tree. Its filename was string-memchr_inv-speed-improvements.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ From: Akinobu Mita <akinobu.mita@xxxxxxxxx> Subject: string: memchr_inv() speed improvements - Generate a 64-bit pattern more efficiently memchr_inv needs to generate a 64-bit pattern filled with a target character. The operation can be done by more efficient way. - Don't call the slow check_bytes() if the memory area is 64-bit aligned memchr_inv compares contiguous 64-bit words with the 64-bit pattern as much as possible. The outside of the region is checked by check_bytes() that scans for each byte. Unfortunately, the first 64-bit word is unexpectedly scanned by check_bytes() even if the memory area is aligned to a 64-bit boundary. Both changes were originally suggested by Eric Dumazet. Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx> Suggested-by: Eric Dumazet <eric.dumazet@xxxxxxxxx> Cc: Brian Norris <computersforpeace@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/string.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff -puN lib/string.c~string-memchr_inv-speed-improvements lib/string.c --- a/lib/string.c~string-memchr_inv-speed-improvements +++ a/lib/string.c @@ -785,12 +785,24 @@ void *memchr_inv(const void *start, int if (bytes <= 16) return check_bytes8(start, value, bytes); - value64 = value | value << 8 | value << 16 | value << 24; - value64 = (value64 & 0xffffffff) | value64 << 32; - prefix = 8 - ((unsigned long)start) % 8; + value64 = value; +#if defined(ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 + value64 *= 0x0101010101010101; +#elif defined(ARCH_HAS_FAST_MULTIPLIER) + value64 *= 0x01010101; + value64 |= value64 << 32; +#else + value64 |= value64 << 8; + value64 |= value64 << 16; + value64 |= value64 << 32; +#endif + prefix = (unsigned long)start % 8; if (prefix) { - u8 *r = check_bytes8(start, value, prefix); + u8 *r; + + prefix = 8 - prefix; + r = check_bytes8(start, value, prefix); if (r) return r; start += prefix; _ Patches currently in -mm which might be from akinobu.mita@xxxxxxxxx are origin.patch linux-next.patch ocfs2-use-find_last_bit.patch ocfs2-use-bitmap_weight.patch sysctl-use-bitmap-library-functions.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html