Messages in this thread | | | From | (Eric W. Biederman) | Date | Fri, 19 Jun 2009 18:28:49 -0700 | Subject | Re: [patch] ipv4: don't warn about skb ack allocation failures |
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David Rientjes <rientjes@google.com> writes:
> On Fri, 19 Jun 2009, Eric W. Biederman wrote: > >> But Mr. Reintjes if you really want the traces I can set up >> an script to email them to you every time it happens. Say about >> 1 a minute from my paltry little farm of machines. >> > > Perhaps you missed my email where I suggested emitting the page allocation > warnings only when CONFIG_DEBUG_VM is enabled. It's at > http://lkml.org/lkml/2009/6/18/355. > > We can then keep the __GFP_NOFAIL flag to indicate that the warnings > should never be emitted for that allocation, regardless of the .config. > > It's funny, though, that the problem that originally started this thread > was quickly diagnosed because of these messages. As far as I know, my > suggestion to increase /proc/sys/vm/dirty_background_ratio to kick pdflush > earlier has prevented the slab allocation failures and not required > delayed acks for nfsd.
increase?
Perhaps then the problem is simply dirty_background_ratio. Is the vm not properly autotuning?
With a 50MB/s disk I wonder what the proper window size is. Several gigabytes as implied by a 5% or a 10% dirty_background_ratio seems absurd. TCP sockets seem to get along fine with even large latencies and windows measured in megabytes not gigabytes.
This does explain a few things.
Eric
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