Messages in this thread | | | Subject | Re: [PATCH] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves | From | Vlastimil Babka <> | Date | Sun, 22 Nov 2015 13:55:31 +0100 |
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On 11.11.2015 14:48, mhocko@kernel.org wrote: > mm/page_alloc.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 8034909faad2..d30bce9d7ac8 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2766,8 +2766,16 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, > goto out; > } > /* Exhausted what can be done so it's blamo time */ > - if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) > + if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) { > *did_some_progress = 1; > + > + if (gfp_mask & __GFP_NOFAIL) { > + page = get_page_from_freelist(gfp_mask, order, > + ALLOC_NO_WATERMARKS|ALLOC_CPUSET, ac); > + WARN_ONCE(!page, "Unable to fullfil gfp_nofail allocation." > + " Consider increasing min_free_kbytes.\n");
It seems redundant to me to keep the WARN_ON_ONCE also above in the if () part? Also s/gfp_nofail/GFP_NOFAIL/ for consistency?
Hm and probably out of scope of your patch, but I understand the WARN_ONCE (WARN_ON_ONCE) to be _ONCE just to prevent a flood from a single task looping here. But for distinct tasks and potentially far away in time, wouldn't we want to see all the warnings? Would that be feasible to implement?
> + } > + } > out: > mutex_unlock(&oom_lock); > return page; >
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