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Message-ID: <86802c440912121757g474a7df4od6b50f6d5a210cf0@mail.gmail.com>
Date: Sat, 12 Dec 2009 17:57:51 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: David Miller <davem@...emloft.net>,
Eric Dumazet <eric.dumazet@...il.com>
Cc: mingo@...e.hu, sri@...ibm.com, herbert@...dor.apana.org.au,
torvalds@...ux-foundation.org, sjayaraman@...e.de,
linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: nfs broken in net-next? -- now in mainline -- bisected:
d9f5950f90292f7cc42834338dfd5f44dc4cc4ca
On Sat, Dec 12, 2009 at 5:05 PM, Yinghai Lu <yinghai@...nel.org> wrote:
>
> [f86dcc5aa8c7908f2c287e7a211228df599e3e71] udp: dynamically
> size hash tables at boot time
commit f86dcc5aa8c7908f2c287e7a211228df599e3e71
Author: Eric Dumazet <eric.dumazet@...il.com>
Date: Wed Oct 7 00:37:59 2009 +0000
udp: dynamically size hash tables at boot time
UDP_HTABLE_SIZE was initialy defined to 128, which is a bit small for
several setups.
4000 active UDP sockets -> 32 sockets per chain in average. An
incoming frame has to lookup all sockets to find best match, so long
chains hurt latency.
Instead of a fixed size hash table that cant be perfect for every
needs, let UDP stack choose its table size at boot time like tcp/ip
route, using alloc_large_system_hash() helper
Add an optional boot parameter, uhash_entries=x so that an admin can
force a size between 256 and 65536 if needed, like thash_entries and
rhash_entries.
dmesg logs two new lines :
[ 0.647039] UDP hash table entries: 512 (order: 0, 4096 bytes)
[ 0.647099] UDP Lite hash table entries: 512 (order: 0, 4096 bytes)
Maximal size on 64bit arches would be 65536 slots, ie 1 MBytes for non
debugging spinlocks.
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
cause the problem: nfs mount fail.
the setup is:
64bit kernel, have all needed drivers in kernel, and boot with
ip=dhcp, root disk is 256M ramdisk.
then try to mount nfs....
YH
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