Messages in this thread | | | Date | Tue, 6 Jul 2021 13:26:53 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v2 1/2] mm/vmalloc: Use batched page requests in bulk-allocator |
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On Mon, 5 Jul 2021 19:05:36 +0200 "Uladzislau Rezki (Sony)" <urezki@gmail.com> wrote:
> In case of simultaneous vmalloc allocations, for example it is 1GB and > 12 CPUs my system is able to hit "BUG: soft lockup" for !CONFIG_PREEMPT > kernel. > > <snip> > ... > > are obtained, i.e. do batched page requests adding cond_resched() meanwhile > to reschedule. Batched value is hard-coded and is 100 pages per call. > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Can we please have a Fixes: for this?
Is this fix important enough for 4.14-rcx? I think so...
> --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2785,10 +2785,32 @@ vm_area_alloc_pages(gfp_t gfp, int nid, > * to fails, fallback to a single page allocator that is > * more permissive. > */ > - if (!order) > - nr_allocated = alloc_pages_bulk_array_node( > - gfp, nid, nr_pages, pages); > - else > + if (!order) { > + while (nr_allocated < nr_pages) { > + int nr, nr_pages_request; > + > + /* > + * A maximum allowed request is hard-coded and is 100 > + * pages per call. That is done in order to prevent a > + * long preemption off scenario in the bulk-allocator > + * so the range is [1:100]. > + */ > + nr_pages_request = min(100, (int)(nr_pages - nr_allocated));
Yes, they types are all over the place.
nr_pages: unsigned long nr_allocated: unsigned int nr, nr_pages_request: int
Can we please choose the most appropriate type and use that consistently?
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