Comment 564 for bug 620074

Sorry for interrupting your research with my naive question, but does this bug have clear steps to reproduce it?

The initial comment says 'starting a new shell takes minutes' after the system is left with dd running for significant time.

But for me shells/browsers etc take just maybe 1 or 2 seconds longer to start after I have 'stress -d 1' or 'dd if=/dev/zero of=bigfile bs=1M' running for ~10 minutes (bigfile is 30Gb after my tests, dirty blocks quickly reach ~670M (3.67G RAM total) and stay there.

The small file test that I accidentally ran with TWO simultaneous bigfile dd processes in the background finished in 0.073s (or is this bad?):

$ dd if=/dev/zero of=/tmp/bigfile bs=1M count=30000 conv=fdatasync & sleep 30 ; time dd if=/dev/zero of=/tmp/smallfile bs=4k count=1 conv=fdatasync
[2] 27953
1+0 records in
1+0 records out
4096 bytes (4.1 kB) copied, 0.0718053 s, 57.0 kB/s

real 0m0.073s
user 0m0.001s
sys 0m0.001s

dd: writing `/tmp/bigfile': No space left on device
dd: writing `/var/tmp/bigfile': No space left on device
22891+0 records in
22890+0 records out
24002064384 bytes (24 GB) copied, 1211.53 s, 19.8 MB/s
21957+0 records in
21956+0 records out
23022534656 bytes (23 GB) copied, 1189.07 s, 19.4 MB/s

[1]- Exit 1 dd if=/dev/zero of=/var/tmp/bigfile bs=1M count=100000 conv=fdatasync
[2]+ Exit 1 dd if=/dev/zero of=/tmp/bigfile bs=1M count=30000 conv=fdatasync

I'm noticing loss of interactivity when my RAM gets filled up and swap grows >500M, but this bug is not about such case is it?

Could it be my HW on latest stable vanilla 2.6.38.2 amd64 (swappiness 20, the rest being defaults)? Or could I have just configured my kernel in some genius way?

[ 2.051391] ata1.00: ATA-8: HITACHI HTS545025B9A300, PB2ZC61H, max UDMA/100
[ 2.054162] ata1.00: 488397168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA
[ 2.065605] ata1.00: configured for UDMA/100
[ 2.087958] scsi 0:0:0:0: Direct-Access ATA HITACHI HTS54502 PB2Z PQ: 0 ANSI: 5

$ sudo hdparm -i /dev/sda

/dev/sda:

 Model=HITACHI HTS545025B9A300, FwRev=PB2ZC61H, SerialNo=100408PBNXXXXXXXXXX
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
 BuffType=DualPortCache, BuffSize=7208kB, MaxMultSect=16, MultSect=off
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=488397168
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes: pio0 pio1 pio2 pio3 pio4
 DMA modes: mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
 AdvancedPM=yes: mode=0x80 (128) WriteCache=enabled
 Drive conforms to: unknown: ATA/ATAPI-2,3,4,5,6,7

PS: I'm on ext3