Messages in this thread | | | Subject | Re: [Patch v2] skbuff: Hide GFP_ATOMIC page allocation failures for dropped packets | From | Eric Dumazet <> | Date | Mon, 27 May 2013 15:25:20 -0700 |
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On Mon, 2013-05-27 at 13:39 -0400, Rik van Riel wrote: > On 05/26/2013 04:19 PM, atomlin@redhat.com wrote: > > From: Aaron Tomlin <atomlin@redhat.com> > > > > Since v1: > > - Removed unnecessary parentheses > > > > ---8<--- > > > > Failed GFP_ATOMIC allocations by the network stack result in dropped > > packets, which will be received on a subsequent retransmit, and an > > unnecessary, noisy warning with a kernel backtrace.
This claim is wrong, only some protocols deal with retransmits.
> > > > These warnings are harmless, but they still cause users to panic and > > file bug reports over dropped packets. It would be better to hide the > > failed allocation warnings and backtraces, and let retransmits handle > > dropped packets quietly. > > Yes please. Getting memory management bug reports for > dropped network packets got old years ago. Lets get > rid of those messages.
I am only wondering why this path has anything needing special attention, over thousands of kmalloc() like call sites in the kernel.
If mm allocation warnings are useless, just make __GFP_NOWARN the default, and save us thousand of patches (adding the __GFP_NOWARN everywhere)
Truth is : some network drivers don't deal very well with allocation errors. mlx4 for example absolutely wants order-2 pages in RX path, with no fallback to order-0 pages.
So I am not against this patch, but I can not really acknowledge it, sorry.
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