On Fri, Jul 29, 2011 at 05:39:29PM +0800, Minchan Kim wrote: > On Thu, Jul 28, 2011 at 04:13:09PM +0800, Shaohua Li wrote: > > cleanup kswapd_try_to_sleep() a little bit. Sometimes kswapd doesn't > > really sleep. In such case, don't call prepare_to_wait/finish_wait. > > It just wastes CPU. > > > > Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx> > > And it increases just code size a little bit even without big benefit of CPU. > You said it's cleanup but I doubt how it helps readability. > So code itself dosn't have a problem but I don't like it. > > barrios@barrios-desktop:~/linux-mmotm$ size mm/vmscan.o.old > text data bss dec hex filename > 10271 30 8 10309 2845 mm/vmscan.o.old > barrios@barrios-desktop:~/linux-mmotm$ size mm/vmscan.o > text data bss dec hex filename > 10287 30 8 10325 2855 mm/vmscan.o I'm curious why the size is increased, the patch doesn't add new code. Maybe gcc has different optimization. This hasn't big benefit for sure, but both prepare_to_wait/finish_wait use spinlock, it's expensive operation even without contention. From this point view, it has benefit because we don't blindly call them. But anyway, it's a trival patch. I'm fine if it's rejected. Thanks, Shaohua -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>