On Thu, 2011-11-10 at 10:23 +0800, Minchan Kim wrote: > So long contents. > Let's remove it. > > On Thu, Nov 10, 2011 at 10:07:10AM +0800, Shaohua Li wrote: > > <snip> > > > > > Coudn't we make both sides good? > > > > > > > > Here is my quick patch. > > > > How about this? > > > > It doesn't split THPs in page_list but still reclaims non-THPs so > > > > I think it doesn't changed old behavior a lot. > > > I like this idea, will do some test soon. > > hmm, this doesn't work as expected. The putback_lru_page() messes lru. > > This isn't a problem if the page will be written since > > rotate_reclaimable_page() will fix the order. I got worse data than my > > v2 patch, eg, more thp_fallbacks, mess lru order, more pages are > > scanned. We could add something like putback_lru_page_tail, but I'm not > > Hmm, It's not LRU mess problem. but it's just guessing and you might be right > because you have a workload and can test it. > > My guessing is that cull_mlocked reset synchronus page reclaim. > Could you test this patch, again? no, I traced it, and lru mess. putback_lru_page() adds the page to lru head instead of tail. > And, if the problem cause by LRU mess, I think it is valuable with adding putback_lru_page_tail > because thp added lru_add_page_tail, too. I want to put all remaining pages back to lru tail if a huge page is split, because enough pages are reclaimed. So this needs adding something like putback_lru_pages_tail(), not complicated, but a lot of code. And if there are parallel reclaimer, we still have lru mess. My test already shows it. Still worthy? 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>