Date: Tue, 01 Jan 2002 06:00:54 +0100 From: "Rogier R. Mulhuijzen" <drwilco@drwilco.net> To: freebsd-hackers@freebsd.org Subject: Running out of bufferspace Message-ID: <5.1.0.14.0.20020101054451.00b35370@mail.drwilco.net>
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Hi,
First of all happy new year, etc. =)
My problem: I'm writing a device driver kernel module that uses kernel
level sosend() from the d_write write() function. But it runs out of
bufferspace (error 55) when I really stress it (sending 15 megs in 3-4 secs
over UDP with 32 or 60K packets).
Thing is, my mbufs are fine, peak is 1/3rd of max. I also use sowriteable()
to check if it's safe to send, and sbspace() tells me I have the full 128K
sndbuf that I configured available.
So I have 2 questions...
1) which buffers are there that I can run out of here and where can I check
their status?
2) Should I free() the uio I get from userspace after I have passed it to
the sosend?
Side note on 1): after I run out of bufferspace with my little driver the
box continues to function fine as far as I can tell, except that
mount_smbfs has trouble:
[ root@hera:~ ] # truss mount -t smbfs //drwilco@ceres/D$ /ceres/d_drive/
readlink("/etc/malloc.conf",0xbfbffa94,63) ERR#2 'No such file or
directory'
mmap(0x0,4096,0x3,0x1002,-1,0x0) = 671551488 (0x28071000)
break(0x807c000) = 0 (0x0)
break(0x807d000) = 0 (0x0)
open(".",0,00) = 3 (0x3)
chdir(0xbfbff090) = 0 (0x0)
sigaction(SIGSYS,0xbfbfeaac,0xbfbfea94) = 0 (0x0)
__getcwd(0xbfbff090,0x400) = 0 (0x0)
sigaction(SIGSYS,0xbfbfea94,0x0) = 0 (0x0)
fchdir(0x3) = 0 (0x0)
close(3) = 0 (0x0)
stat("/ceres/d_drive",0xbfbfeff4) = 0 (0x0)
fork() = 3331 (0xd03)
smbfs: can't get server address: syserr = No buffer space available
SIGNAL 20
wait4(0xd03,0xbfbff088,0x0,0x0) = 3331 (0xd03)
exit(0x1) process exit, rval = 256
A different tactic could be that I pull a m_devget() or some other mbuf
creation stunt and copy the data from the uio into the mbuf. Do I have to
clear the mbuf and/or uio after passing that mbuf to sosend?
Any pointers (even to some docs, though I've done heavy googling) or hints
would be greatly appreciated.
DocWilco
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