Messages in this thread | | | Date | Wed, 1 Apr 2009 06:09:51 +0200 | From | Johannes Weiner <> | Subject | Re: [PATCH] vmscan: memcg needs may_swap (Re: [patch] vmscan: rename sc.may_swap to may_unmap) |
| |
On Tue, Mar 31, 2009 at 10:48:32AM +0900, KOSAKI Motohiro wrote: > > > Sorry for too late response. > > > I don't know memcg well. > > > > > > The memcg managed to use may_swap well with global page reclaim until now. > > > I think that was because may_swap can represent both meaning. > > > Do we need each variables really ? > > > > > > How about using union variable ? > > > > or Just removing one of them ? > > I hope all may_unmap user convert to using may_swap. > may_swap is more efficient and cleaner meaning.
How about making may_swap mean the following:
@@ -642,6 +639,8 @@ static unsigned long shrink_page_list(st * Try to allocate it some swap space here. */ if (PageAnon(page) && !PageSwapCache(page)) { + if (!sc->map_swap) + goto keep_locked; if (!(sc->gfp_mask & __GFP_IO)) goto keep_locked; if (!add_to_swap(page))
try_to_free_pages() always sets it.
try_to_free_mem_cgroup_pages() sets it depending on whether it really wants swapping, and only swapping, right? But the above would still reclaim already swapped anon pages and I don't know the memory controller.
balance_pgdat() always sets it.
__zone_reclaim() sets it depending on zone_reclaim_mode. The RECLAIM_SWAP bit of this field and its documentation in Documentation/sysctl/vm.txt suggests it also really only means swap.
shrink_all_memory() would be the sole user of may_unmap because it really wants to eat cache first. But this could be figured out on a different occasion.
Hannes
| |