On Thu, 2017-05-04 at 10:33 -0700, Dave Hansen wrote: > On 05/04/2017 08:49 AM, Benjamin Herrenschmidt wrote: > > On Thu, 2017-05-04 at 14:52 +0200, Michal Hocko wrote: > > > But the direct reclaim would be effective only _after_ all other nodes > > > are full. > > > > > > I thought that kswapd reclaim is a problem because the HW doesn't > > > support aging properly but as the direct reclaim works then what is the > > > actual problem? > > > > Ageing isn't isn't completely broken. The ATS MMU supports > > dirty/accessed just fine. > > > > However the TLB invalidations are quite expensive with a GPU so too > > much harvesting is detrimental, and the GPU tends to check pages out > > using a special "read with intend to write" mode, which means it almost > > always set the dirty bit if the page is writable to begin with. > > Why do you have to invalidate the TLB? Does the GPU have a TLB so large > that it can keep thing in the TLB for super-long periods of time? > > We don't flush the TLB on clearing Accessed on x86 normally. Isn't that mostly because x86 relies on non-global pages to be flushed on context switch? Balbir Singh. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
