Messages in this thread | | | Date | Mon, 26 Jun 2017 07:28:27 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH 6/6] mm, migration: do not trigger OOM killer when migrating memory |
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On Fri 23-06-17 13:43:05, Andrew Morton wrote: > On Fri, 23 Jun 2017 10:53:45 +0200 Michal Hocko <mhocko@kernel.org> wrote: > > > From: Michal Hocko <mhocko@suse.com> > > > > Page migration (for memory hotplug, soft_offline_page or mbind) needs > > to allocate a new memory. This can trigger an oom killer if the target > > memory is depleated. Although quite unlikely, still possible, especially > > for the memory hotplug (offlining of memoery). Up to now we didn't > > really have reasonable means to back off. __GFP_NORETRY can fail just > > too easily and __GFP_THISNODE sticks to a single node and that is not > > suitable for all callers. > > > > But now that we have __GFP_RETRY_MAYFAIL we should use it. It is > > preferable to fail the migration than disrupt the system by killing some > > processes. > > I'm not sure which tree this is against...
next-20170623
> > > --- a/mm/memory-failure.c > > +++ b/mm/memory-failure.c > > @@ -1492,7 +1492,8 @@ static struct page *new_page(struct page *p, unsigned long private, int **x) > > > > return alloc_huge_page_node(hstate, nid); > > } else { > > - return __alloc_pages_node(nid, GFP_HIGHUSER_MOVABLE, 0); > > + return __alloc_pages_node(nid, > > + GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL, 0); > > } > > } > > new_page() is now > > static struct page *new_page(struct page *p, unsigned long private, int **x) > { > int nid = page_to_nid(p); > > return new_page_nodemask(p, nid, &node_states[N_MEMORY]); > } > > and new_page_nodemask() uses __GFP_RETRY_MAYFAIL so I simply dropped > the above hunk.
Ohh, right. This is http://lkml.kernel.org/r/20170622193034.28972-4-mhocko@kernel.org. I've just didn't realize it was not in mmotm yet. So yes the hunk can be dropped, new_page_nodemask does what we need.
Sorry about that -- Michal Hocko SUSE Labs
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