Messages in this thread | | | Subject | Re: [rfc patch-rt] radix-tree: Partially disable memcg accounting in radix_tree_node_alloc() | From | Mike Galbraith <> | Date | Fri, 06 Jan 2017 11:52:59 +0100 |
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On Fri, 2017-01-06 at 09:55 +0100, Michal Hocko wrote: > On Fri 06-01-17 09:13:23, Mike Galbraith wrote: > > radix-tree: Partially disable memcg accounting in radix_tree_node_alloc() > > > > Having no preload, which turns accounting off for non-rt kernels, trying to > > allocate coming from shmem_fault() when memcg is full sends us scurrying off > > to pagefault_out_of_memory(), with dramatic (usually terminal) consequences. > > LTP's madvise06 testcase triggers this quite well, and per gitk, the below > > was the beginning of RT memcg woes. > > > > 58e698af4c63 radix-tree: account radix_tree_node to memory cgroup > > > > Turn memcg accounting off for RT in the problematic path. > > I am really wondering why this is RT specific and the non RT kernels > doesn't have any problem.
For all I know, there may be a scenario for non-RT to explode, but the madvise06 testcase that thoroughly nails RT ain't it.
-Mike
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