Date: Thu, 12 Aug 2004 16:10:20 +0200 From: Pawel Malachowski <pawmal-posting@freebsd.lublin.pl> To: freebsd-gnats-submit@FreeBSD.org, eugen@grosbein.pp.ru Cc: freebsd-bugs@freebsd.org Subject: Re: kern/46557: ipfw pipe show fails with lots of queues Message-ID: <20040812141020.GA28613@shellma.zin.lublin.pl>
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Hello,
I've just hit this problem on my 4.10-STABLE dummynet shaper.
Very bad, since `ipfw pipe show N' + net.inet.ip.dummynet.expire=0 is
quite useful for grabbing some per-user statistics. :/
Here are more details what is going on. I hope someone will look at this and
explain why malloc() can fail here and what can be done to prevent this.
% ipfw pipe show
ipfw: getsockopt(IP_DUMMYNET_GET): No buffer space available
This command invokes getsockopt() trying to fetch all pipes data from kernel
to userland.
Kernel part of this is being done in dummynet_get(), which tries to allocate
buf big (previously computed size) enough for all data:
buf = malloc(size, M_TEMP, M_NOWAIT);
if (buf == 0) {
splx(s);
return ENOBUFS ;
}
This malloc() call fails sometimes on loaded system (10k-70k of dynamic
pipes + make buildworld;)) causing `ipfw pipe show' command failure.
I've registered temporary MALLOC_DEFINE M_YOYO and changed this malloc/free
from M_TEMP to M_YOYO, ;) so I can easily track this in `vmstat -m' output:
1. Quite early (no problems):
Type InUse MemUse HighUse Limit Requests Limit Limit Size(s)
IpFw/IpAcct 113 14K 14K 42107K 113 0 0 64,128,256
yoyo 0 0K 120K 42107K 1 0 0 128K
dummynet 1612 311K 313K 42107K 139366 0 0 16,128,256,4K
Memory Totals: In Use Free Requests
3921K 32K 173824
2. After some time malloc() in dummynet_get() fails and:
Type InUse MemUse HighUse Limit Requests Limit Limit Size(s)
IpFw/IpAcct 113 14K 14K 42107K 113 0 0 64,128,256
yoyo 0 0K 2828K 42107K 12913 0 0 128K,512K
dummynet 21432 2790K 3354K 42107K 9804136 0 0 16,128,256,512,1K,4K
Memory Totals: In Use Free Requests
9932K 3029K 14216860
In /sbin/ipfw2, list():
(do_cmd(ocmd, data, (uintptr_t)&nbytes) < 0)
nbytes were 2188288 // In loop, I +1024 numbytes instead of *2+200, ignore this
In ip_dummynet.c, dummynet_get():
buf = malloc(size, M_YOYO, M_NOWAIT); // note: M_TEMP => M_YOYO
size was 2390416 and malloc() failed.
--
Paweł Małachowski
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