The patch titled lib/extable.c: remove an expensive integer divide in search_extable() has been removed from the -mm tree. Its filename was lib-extablec-removes-an-expensive-integer-divide-in-search_extable.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/ ------------------------------------------------------ Subject: lib/extable.c: remove an expensive integer divide in search_extable() From: Eric Dumazet <dada1@xxxxxxxxxxxxx> Actual code let compiler generates idiv instruction on x86. Using a right shift is OK here and readable as well. Before patch 10: 57 push %edi 11: 56 push %esi 12: 89 d6 mov %edx,%esi 14: 53 push %ebx 15: 89 c3 mov %eax,%ebx 17: eb 22 jmp 3b <search_extable+0x2b> 19: 89 f0 mov %esi,%eax 1b: ba 02 00 00 00 mov $0x2,%edx 20: 29 d8 sub %ebx,%eax 22: 89 d7 mov %edx,%edi 24: c1 f8 03 sar $0x3,%eax 27: 99 cltd 28: f7 ff idiv %edi 2a: 8d 04 c3 lea (%ebx,%eax,8),%eax 2d: 39 08 cmp %ecx,(%eax) ... After patch 00000010 <search_extable>: 10: 53 push %ebx 11: 89 c3 mov %eax,%ebx 13: eb 18 jmp 2d <search_extable+0x1d> 15: 89 d0 mov %edx,%eax 17: 29 d8 sub %ebx,%eax 19: c1 f8 04 sar $0x4,%eax 1c: 8d 04 c3 lea (%ebx,%eax,8),%eax 1f: 39 08 cmp %ecx,(%eax) ... Signed-off-by: Eric Dumazet <dada1@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/extable.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff -puN lib/extable.c~lib-extablec-removes-an-expensive-integer-divide-in-search_extable lib/extable.c --- a/lib/extable.c~lib-extablec-removes-an-expensive-integer-divide-in-search_extable +++ a/lib/extable.c @@ -57,10 +57,10 @@ search_extable(const struct exception_ta while (first <= last) { const struct exception_table_entry *mid; - mid = (last - first) / 2 + first; + mid = ((last - first) >> 1) + first; /* - * careful, the distance between entries can be - * larger than 2GB: + * careful, the distance between value and insn + * can be larger than MAX_LONG: */ if (mid->insn < value) first = mid + 1; _ Patches currently in -mm which might be from dada1@xxxxxxxxxxxxx are origin.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