Re: lost connection to test machine (4)
From: Dennis Zhou <hidden>
Date: 2018-02-13 17:34:58
Also in:
lkml
Hi Eric, On Tue, Feb 13, 2018 at 05:35:26AM -0800, Eric Dumazet wrote:
quoted hunk ↗ jump to hunk
Also I would consider using this fix as I had warnings of cpus being stuck there for more than 50 ms :diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c index 9158e5a81391ced4e268e3d5dd9879c2bc7280ce..6309b01ceb357be01e857e5f899429403836f41f 100644 --- a/mm/percpu-vm.c +++ b/mm/percpu-vm.c@@ -92,6 +92,7 @@ static int pcpu_alloc_pages(struct pcpu_chunk *chunk, *pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0); if (!*pagep) goto err; + cond_resched(); } } return 0;
This function gets called from pcpu_populate_chunk while holding the pcpu_alloc_mutex and is called from two scenarios. First, when an allocation occurs to a place without backing pages, and second when the workqueue item is scheduled to replenish the number of empty pages. So, I don't think this is a good idea. My understanding is if we're seeing warnings here, that means we're struggling to find backing pages. I believe adding __GFP_NORETRY on the workqueue path as Tejun mentioned above would help with warnings as well, but not if they are caused by the allocation path. Thanks, Dennis