Re: [PATCH] net/skbuff: silence warnings under memory pressure

From: Eric Dumazet
Date: Fri Aug 30 2019 - 11:12:03 EST

On 8/30/19 4:57 PM, Qian Cai wrote:
> When running heavy memory pressure workloads, the system is throwing
> endless warnings below due to the allocation could fail from
> __build_skb(), and the volume of this call could be huge which may
> generate a lot of serial console output and cosumes all CPUs as
> warn_alloc() could be expensive by calling dump_stack() and then
> show_mem().
> Fix it by silencing the warning in this call site. Also, it seems
> unnecessary to even print a warning at all if the allocation failed in
> __build_skb(), as it may just retransmit the packet and retry.

Same patches are showing up there and there from time to time.

Why is this particular spot interesting, against all others not adding __GFP_NOWARN ?

Are we going to have hundred of patches adding __GFP_NOWARN at various points,
or should we get something generic to not flood the syslog in case of memory pressure ?