Le jeudi 22 juillet 2010 à 17:39 +0200, Jan Engelhardt a écrit : > Never say never. "long" already bit people in the past, and now we > have that CONFIG_COMPAT stuff. > I know pretty well the "long" problem, I received one of the first alpha machine ever built in the world (DEC 3000 AXP, with a fast 133 MHz cpu ;) ), before I began to use Linux :) > If invert is the only flag, perhaps it makes sense to use __u8 > for it. > Quite frankly it brings more problems than plain u32 - Possible security problems (padding bytes). Not applicable to iptables. - Some arches have slow byte/short accesses (21064 for example :) ) "int" is the natural type, fast on all arches. - Given alignment requirements of iptables rules, using less than 32bits here saves no ram. But I dont care that much. I even see compiler doesnt want to use a XOR instruction : 00000018 <cpu_mt>: 18: 55 push %ebp 19: 8b 42 04 mov 0x4(%edx),%eax 1c: 64 8b 15 00 00 00 00 mov %fs:0x0,%edx 23: 89 e5 mov %esp,%ebp 25: 5d pop %ebp 26: 39 10 cmp %edx,(%eax) 28: 0f 94 c2 sete %dl 2b: 0f b6 d2 movzbl %dl,%edx 2e: 3b 50 04 cmp 0x4(%eax),%edx 31: 0f 95 c0 setne %al 34: c3 ret -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
