On Mon, 5 Jul 2021 19:05:36 +0200 "Uladzislau Rezki (Sony)" <urezki@xxxxxxxxx> 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@xxxxxxxxx>
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?
