Messages in this thread | | | Date | Wed, 14 Dec 2005 22:06:46 -0800 | From | Stephen Hemminger <> | Subject | Re: [RFC][PATCH 0/3] TCP/IP Critical socket communication mechanism |
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On Thu, 15 Dec 2005 06:42:45 +0100 Andi Kleen <ak@suse.de> wrote:
> On Wed, Dec 14, 2005 at 08:30:23PM -0800, David S. Miller wrote: > > From: Matt Mackall <mpm@selenic.com> > > Date: Wed, 14 Dec 2005 19:39:37 -0800 > > > > > I think we need a global receive pool and per-socket send pools. > > > > Mind telling everyone how you plan to make use of the global receive > > pool when the allocation happens in the device driver and we have no > > idea which socket the packet is destined for? What should be done for > > In theory one could use multiple receive queue on intelligent enough > NIC with the NIC distingushing the sockets. > > But that would be still a nasty "you need advanced hardware FOO to avoid > subtle problem Y" case. Also it would require lots of driver hacking. > > And most NICs seem to have limits on the size of the socket tables for this, which > means you would end up in a "only N sockets supported safely" situation, > with N likely being quite small on common hardware. > > I think the idea of the original poster was that just freeing non critical packets > after a short time again would be good enough, but I'm a bit sceptical > on that. > > > I truly dislike these patches being discussed because they are a > > complete hack, and admittedly don't even solve the problem fully. I > > I agree. > > > I think GFP_ATOMIC memory pools are more powerful than they are given > > credit for. There is nothing preventing the implementation of dynamic > > Their main problem is that they are used too widely and in a lot > of situations that aren't really critical.
Most of the use of GFP_ATOMIC is by stuff that could fail but can't sleep waiting for memory. How about adding a GFP_NORMAL for allocations while holding a lock.
#define GFP_NORMAL (__GFP_NOMEMALLOC)
Then get people to change the unneeded GFP_ATOMIC's to GFP_NORMAL in places where the error paths are reasonable. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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