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. -- 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>
