Morrison, Tom wrote:
Additional information - the ~file size this is caused
is somewhere close to 260Mbytesfiles.
If I create a ~260Mbytes file - my program finishes creating
the file - but ~5 seconds later (I timed this by hitting enter
on the console every second after completion of the command
that should have done a fsync of the created file before exiting)...
It hangs...
I did a little playing around with /proc/sys/dev/scsi/logging_level
(set to 0x7) - and it seems that the kernel/box locks up after
this line:
scsi_add_timer: scmd: efca83c0, time: 7500, (c0160660)
scsi_delete_timer: scmd: efca83c0, rtn: 1
scsi_add_timer: scmd: efca8840, time: 7500, (c0160660)
Further analysis (setting logging level to 65535 (0xFFFF)
Has the following behavior down low) -
scsi_add_timer: scmd: efca8960, time: 7500, (c0160660)
sd 0:0:0:0: [sda] Send: 0xefca8960
sd 0:0:0:0: [sda] CDB: Write(10): 2a 00 00 47 92 27 00 01 48 00
buffer = 0xc0553040, bufflen = 167936, done = 0xc016b194,
queuecommand
0xc017ed34
leaving scsi_dispatch_cmnd()
scsi_delete_timer: scmd: efca8960, rtn: 1
sd 0:0:0:0: [sda] Done: 0xefca8960 SUCCESS
sd 0:0:0:0: [sda] Result: hostbyte=DID_OK
driverbyte=DRIVER_OK,SUGGEST_OK
sd 0:0:0:0: [sda] CDB: Write(10): 2a 00 00 47 92 27 00 01 48 00
sd 0:0:0:0: [sda] scsi host busy 1 failed 0
sd 0:0:0:0: Notifying upper driver of completion (result 0)
scsi_add_timer: scmd: efca82a0, time: 7500, (c0160660)
sd 0:0:0:0: [sda] Send: 0xefca82a0
sd 0:0:0:0: [sda] CDB: Write(10): 2a 00 00 47 93 6f 00 02 40 00
buffer = 0xef5734c0, bufflen = 294912, done = 0xc016b194,
queuecommand
0xc017ed34
leaving scsi_dispatch_cmnd()
Nothing more - it hangs!
This is really a nasty problem!!!!
..
Yes. It's particularly nasty because, as of yet, I haven't seen anything
to lead me to conclude *which* kernel subsystem is locking up.
It could be the block layer.
It could be some PPC arch bug.
It could be mm.
It could even be the CPU scheduler.
Those messages above could help.
Now we just need somebody to interpret them,
and examine the code paths that follow to see
where it might be possible to get stuck.
The SCSI/libata layers by themselves could lock up the I/O,
but not the entire machine..
Cheers
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