On Tue, Dec 27, 2011 at 01:44:05PM +0900, KAMEZAWA Hiroyuki wrote:To me, it seems kswapd does usual work...reclaim small memory until free
gets enough. And it seems 'dd' allocates its memory from ZONE_DMA32 because
of gfp_t fallbacks.
1. why shrink_slab() should be called per zone, which is not zone aware.
Isn't it enough to call it per priority ?
It is intended that it should be zone aware, but the current
shrinkers only have global LRUs and hence cannot discriminate
between objects from different zones easily. And if only a single
node/zone is being scanned, then we still have to call shirnk_slab()
to try to free objects in that zone/node, despite it's current
I have some prototype patches that make the major slab caches and
shrinkers zone/node aware - that is the eventual goal here - but
first all the major slab cache LRUs need to be converted to be node
aware first. Then we can pass a nodemask into shrink_slab() and down
to the shrinkers so that those that have per-node LRUs can scan only
the appropriate nodes for objects to free. This is someting that I'm
working on in my spare time, but I have very little of that at the