On Thu, Nov 10, 2011 at 10:46:07AM +0800, Shaohua Li wrote: > 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. I knew LRU mess happens but I mean I am not sure the culprit is it. > > > 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? If parallel reclaim happens, it can spoil everything. It's really really bad. I perfer adding putback_lru_page_tail with isoloation trick because probably we can use it later about pages which was not able to reclaim by some causes temporally. > > Thanks, > Shaohua > -- Kind regards, Minchan Kim -- 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>