Messages in this thread | | | Date | Fri, 25 Mar 2022 13:58:42 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] dma/pool: do not complain if DMA pool is not allocated |
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On Fri 25-03-22 13:25:59, Michal Hocko wrote: > From: Michal Hocko <mhocko@suse.com> > > we have a system complainging about order-5 allocation for the DMA pool. > This is something that a674e48c5443 ("dma/pool: create dma atomic pool > only if dma zone has managed pages") has already tried to achieve but I > do not think it went all the way to have it covered completely. In this > particular case has_managed_dma() will not work because: > [ 0.678539][ T0] Initmem setup node 0 [mem 0x0000000000001000-0x000000027dffffff] > [ 0.686316][ T0] On node 0, zone DMA: 1 pages in unavailable ranges > [ 0.687093][ T0] On node 0, zone DMA32: 36704 pages in unavailable ranges > [ 0.694278][ T0] On node 0, zone Normal: 53252 pages in unavailable ranges > [ 0.701257][ T0] On node 0, zone Normal: 8192 pages in unavailable ranges
Dang, I have just realized that I have misread the boot log and it has turned out that a674e48c5443 is covering my situation because the allocation failure message says: Node 0 DMA free:0kB boost:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:636kB managed:0kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
I thought there are only few pages in the managed by the DMA zone. This is still theoretically possible so I think __GFP_NOWARN makes sense here but it would require to change the patch description.
Is this really worth it?
> > The allocation failure on the DMA zone shouldn't be really critical for > the system operation so just silence the warning instead. > > Signed-off-by: Michal Hocko <mhocko@suse.com> > --- > kernel/dma/pool.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c > index 4d40dcce7604..1bf6de398986 100644 > --- a/kernel/dma/pool.c > +++ b/kernel/dma/pool.c > @@ -205,7 +205,7 @@ static int __init dma_atomic_pool_init(void) > ret = -ENOMEM; > if (has_managed_dma()) { > atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size, > - GFP_KERNEL | GFP_DMA); > + GFP_KERNEL | GFP_DMA | __GFP_NOWARN); > if (!atomic_pool_dma) > ret = -ENOMEM; > } > -- > 2.30.2
-- Michal Hocko SUSE Labs
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