On Tue, Mar 30, 2010 at 02:40:07PM +0800, KOSAKI Motohiro wrote: > > On Tue, 2010-03-30 at 14:08 +0800, KOSAKI Motohiro wrote: > > > Hi > > > > > > > Commit 84b18490d1f1bc7ed5095c929f78bc002eb70f26 introduces a regression. > > > > With it, our tmpfs test always oom. The test has a lot of rotated anon > > > > pages and cause percent[0] zero. Actually the percent[0] is a very small > > > > value, but our calculation round it to zero. The commit makes vmscan > > > > completely skip anon pages and cause oops. > > > > An option is if percent[x] is zero in get_scan_ratio(), forces it > > > > to 1. See below patch. > > > > But the offending commit still changes behavior. Without the commit, we scan > > > > all pages if priority is zero, below patch doesn't fix this. Don't know if > > > > It's required to fix this too. > > > > > > Can you please post your /proc/meminfo > > attached. > > > and reproduce program? I'll digg it. > > our test is quite sample. mount tmpfs with double memory size and store several > > copies (memory size * 2/G) of kernel in tmpfs, and then do kernel build. > > for example, there is 3G memory and then tmpfs size is 6G and there is 6 > > kernel copy. > > Wow, tmpfs size > memsize! > > > > > Very unfortunately, this patch isn't acceptable. In past time, vmscan > > > had similar logic, but 1% swap-out made lots bug reports. > > can you elaborate this? > > Completely restore previous behavior (do full scan with priority 0) is > > ok too. > > This is a option. but we need to know the root cause anyway. I thought I mentioned the root cause in first mail. My debug shows recent_rotated[0] is big, but recent_rotated[1] is almost zero, which makes percent[0] 0. But you can double check too. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>