Bug#628718: linux-2.6: Swap on encrypted volume slows system to a crawl (not explicable by encryption overhead)
+1 on this problem, im experiencing the same thing :(
Server swaps out, and I get this for 10+ minutes..
top - 22:44:01 up 22:52, 10 users, load average: 20.62, 12.75, 6.58
Tasks: 394 total, 2 running, 392 sleeping, 0 stopped, 0 zombie
Cpu0 : 24.7%us, 27.0%sy, 0.0%ni, 0.0%id, 31.9%wa, 0.0%hi, 16.4%si,
0.0%st
Cpu1 : 8.3%us, 7.9%sy, 0.0%ni, 39.4%id, 44.4%wa, 0.0%hi, 0.0%si,
0.0%st
Cpu2 : 9.3%us, 32.1%sy, 0.0%ni, 46.7%id, 11.9%wa, 0.0%hi, 0.0%si,
0.0%st
Cpu3 : 3.3%us, 14.7%sy, 0.0%ni, 50.5%id, 31.3%wa, 0.0%hi, 0.3%si,
0.0%st
Mem: 13358940k total, 13230432k used, 128508k free, 652296k buffers
Swap: 1048568k total, 612468k used, 436100k free, 5717792k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2264 root 20 0 0 0 0 R 51 0.0 40:31.93 [kcryptd]
1531 root 20 0 0 0 0 S 20 0.0 1:26.13 [kcryptd]
Total DISK READ: 46.47 M/s | Total DISK WRITE: 21.82 M/s
TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND
6377 be/4 foxx 4.98 M/s 6.84 K/s 0.00 % 99.99 % lb.prod
6378 be/4 foxx 7.29 M/s 10.26 K/s 0.00 % 99.99 % lb.prod
6352 be/3 root 2.01 M/s 0.00 B/s 0.00 % 99.94 % lb.admin
6376 be/4 foxx 6.21 M/s 0.00 B/s 0.00 % 99.91 % lb.prod
6379 be/4 root 1347.58 K/s 0.00 B/s 0.00 % 98.78 % lb.flip
6381 be/4 root 947.41 K/s 13.68 K/s 0.00 % 97.21 % lb.monitor
Total DISK READ: 55.43 M/s | Total DISK WRITE: 0.00 B/s
TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND
2270 be/3 root 0.00 B/s 43.43 K/s 0.00 % 99.99 % [jbd2/dm-5-8]
6376 be/4 foxx 10.77 M/s 43.43 K/s 0.00 % 96.70 % lb.prod
6377 be/4 foxx 6.07 M/s 0.00 B/s 0.00 % 91.63 % lb.prod
6352 be/3 root 390.88 K/s 0.00 B/s 0.00 % 91.08 % lb.admin
6379 be/4 root 390.88 K/s 0.00 B/s 0.00 % 88.48 % lb.flip
6378 be/4 foxx 8.06 M/s 0.00 B/s 0.00 % 83.85 % lb.prod
6375 be/4 foxx 8.31 M/s 0.00 B/s 0.00 % 79.33 % lb.prod
2262 be/4 root 0.00 B/s 0.00 B/s 0.00 % 17.45 % [kdmflush]
1390 be/4 root 0.00 B/s 0.00 B/s 0.00 % 9.54 % [kdmflush]
On 31/05/2011 17:37, SirJective wrote:
Package: linux-2.6
Version: 2.6.38-2
Severity: important
I'm using swap space on an LVM volume on a LUKS-encrypted partition.
Swapping is ridiculously slow (< 1MB/s) whenever I swap to either the encrypted
swap partition, or some file inside an encrypted partition.
It is reasonably fast when swapping to a file on an unencrypted partition.
Normal writes (file copying, dd if=/dev/zero, etc) to the encrypted partition are
reasonably fast (~30MB/s), so the CPU overhead caused by encryption
cannot account for this.
[I posted a similar bug for 2.6.32 to the linux-image-*-686 package in squeeze, which
was probably a bad idea, so I'm posting this to the linux-2.6 source package,
where all the other bugs are posted.]
The real-world impact is that, for example, when I open a huge image in iceweasel
with other stuff already open in the background, the system virtually freezes
up for 15 minutes or more.
-- System Information:
Debian Release: wheezy/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: i386 (i686)
Kernel: Linux 2.6.38-2-686 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
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