Messages in this thread | | | Date | Tue, 23 Feb 2010 10:45:23 +0100 | From | Andrea Righi <> | Subject | Re: [PATCH 2/2] memcg: dirty pages instrumentation |
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On Tue, Feb 23, 2010 at 10:40:40AM +0100, Andrea Righi wrote: > > If vm_highmem_is_dirtyable=0, In that case, we can still return with > > "memcg_memory" which can be more than "memory". IOW, highmem is not > > dirtyable system wide but still we can potetially return back saying > > for this cgroup we can dirty more pages which can potenailly be acutally > > be more that system wide allowed? > > > > Because you have modified dirtyable_memory() and made it per cgroup, I > > think it automatically takes care of the cases of per cgroup dirty ratio, > > I mentioned in my previous mail. So we will use system wide dirty ratio > > to calculate the allowed dirty pages in this cgroup (dirty_ratio * > > available_memory()) and if this cgroup wrote too many pages start > > writeout? > > OK, if I've understood well, you're proposing to use per-cgroup > dirty_ratio interface and do something like: > > unsigned long determine_dirtyable_memory(void) > { > unsigned long memcg_memory, memory; > > memory = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages(); > if (!vm_highmem_is_dirtyable) > memory -= highmem_dirtyable_memory(memory); > > memcg_memory = mem_cgroup_page_state(MEMCG_NR_FREE_PAGES); > if (!memcg_memory) > return memory + 1; /* Ensure that we never return 0 */ > memcg_memory += mem_cgroup_page_state(MEMCG_NR_RECLAIMABLE_PAGES); > if (!vm_highmem_is_dirtyable) > memcg_memory -= highmem_dirtyable_memory(memory) * > mem_cgroup_dirty_ratio() / 100;
ok, this is wrong:
> if (memcg_memory < memory) > return memcg_memory; > }
return min(memcg_memory, memory);
-Andrea
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