Swapfile problem in 6? (was: 6.0: during kernel compilation, 'kernel linking' freezes PC)
--- Rob [EMAIL PROTECTED] wrote: Hi, I have upgraded a Pentium-1 PC from 5 to 6-Stable, which went smoothly. Now I'm running 6 with GENERIC kernel, and I want to compile a new kernel. When I start a new kernel compilation, this process *always* freezes the PC (no crash) when reaching the point of linking kernel; this is 100 percent reproducible!! Then all communication with the PC is frozen; no serial port response, no ssh response etc. However, I can ping the PC. Only power off/on brings the PC back to live. Any idea how I can further investigate. /var/log/messages has no special information while the freezing occurred. The output of 'dmesg' of this PC is here: http://surfion.snu.ac.kr/~lahaye/dmesg Problem kind of solved: As this PC has only 32 MB Ram, I add a swapfile. However, when I compile the new kernel without the swapfile, all goes well. Since the freeze is very reproducible with the swapfile (always at the 'kernel linking' stage), and immediately disappears when I do not use the swapfile, I think there's something wrong with using swapfile in 6.0. Is it? I do this: dd if=/dev/zero of=/swapfile bs=1024k count=128 chmod 0600 /swapfile mdconfig -a -t vnode -f /swapfile -u 0 swapon /dev/md0 Is this OK? Rob. __ Start your day with Yahoo! - Make it your home page! http://www.yahoo.com/r/hs ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Swapfile problem in 6? (was: 6.0: during kernel compilation, 'kernel linking' freezes PC)
On Mon, Nov 14, 2005 at 05:52:42PM -0800, Rob wrote: --- Rob [EMAIL PROTECTED] wrote: Hi, I have upgraded a Pentium-1 PC from 5 to 6-Stable, which went smoothly. Now I'm running 6 with GENERIC kernel, and I want to compile a new kernel. When I start a new kernel compilation, this process *always* freezes the PC (no crash) when reaching the point of linking kernel; this is 100 percent reproducible!! Then all communication with the PC is frozen; no serial port response, no ssh response etc. However, I can ping the PC. Only power off/on brings the PC back to live. Any idea how I can further investigate. /var/log/messages has no special information while the freezing occurred. The output of 'dmesg' of this PC is here: http://surfion.snu.ac.kr/~lahaye/dmesg Problem kind of solved: As this PC has only 32 MB Ram, I add a swapfile. However, when I compile the new kernel without the swapfile, all goes well. Since the freeze is very reproducible with the swapfile (always at the 'kernel linking' stage), and immediately disappears when I do not use the swapfile, I think there's something wrong with using swapfile in 6.0. Is it? I do this: dd if=/dev/zero of=/swapfile bs=1024k count=128 chmod 0600 /swapfile mdconfig -a -t vnode -f /swapfile -u 0 swapon /dev/md0 Is this OK? Looks fine, and I use this myself (on a much larger scale). Are you sure it's freezing and not just taking a really long time? Whenever your system is swapping performance will be terrible, and that goes at least double for swapping onto a file and not a device. What happens if you leave it for an hour or two (or overnight)? Kris pgptYcxFB6Uv8.pgp Description: PGP signature
Re: Swapfile problem in 6? (was: 6.0: during kernel compilation, 'kernel linking' freezes PC)
--- Kris Kennaway [EMAIL PROTECTED] wrote: On Mon, Nov 14, 2005 at 05:52:42PM -0800, Rob wrote: Problem kind of solved: As this PC has only 32 MB Ram, I add a swapfile. However, when I compile the new kernel without the swapfile, all goes well. Since the freeze is very reproducible with the swapfile (always at the 'kernel linking' stage), and immediately disappears when I do not use the swapfile, I think there's something wrong with using swapfile in 6.0. Is it? I do this: dd if=/dev/zero of=/swapfile bs=1024k count=128 chmod 0600 /swapfile mdconfig -a -t vnode -f /swapfile -u 0 swapon /dev/md0 Is this OK? Looks fine, and I use this myself (on a much larger scale). Are you sure it's freezing and not just taking a really long time? Whenever your system is swapping performance will be terrible, and that goes at least double for swapping onto a file and not a device. What happens if you leave it for an hour or two (or overnight)? I left it overnight twice for performing this 'kernel linking' stage. In both cases the machine remained dead. Without the swapfile, this 'kernel linking' stage completes in just about less than a minute. So I think it's not my impatience, but there is another problem with my swapfile or with 6 :). Rob. __ Yahoo! FareChase: Search multiple travel sites in one click. http://farechase.yahoo.com ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Swapfile problem in 6? (was: 6.0: during kernel compilation, 'kernel linking' freezes PC)
On Mon, Nov 14, 2005 at 06:08:27PM -0800, Rob wrote: I left it overnight twice for performing this 'kernel linking' stage. In both cases the machine remained dead. Without the swapfile, this 'kernel linking' stage completes in just about less than a minute. So I think it's not my impatience, but there is another problem with my swapfile or with 6 :). Since you can compile a kernel without it, add DDB, WITNESS and INVARIANTS support, then trigger the deadlock with the swapfile, break to DDB and examine the state of the machine. See the chapter on kernel debugging in the developers handbook for more instructions. Kris pgpJ6WLBy6qWO.pgp Description: PGP signature
Re: Swapfile problem in 6? (was: 6.0: during kernel compilation, 'kernel linking' freezes PC)
--- Kris Kennaway [EMAIL PROTECTED] wrote: On Mon, Nov 14, 2005 at 06:08:27PM -0800, Rob wrote: I left it overnight twice for performing this 'kernel linking' stage. In both cases the machine remained dead. Without the swapfile, this 'kernel linking' stage completes in just about less than a minute. So I think it's not my impatience, but there is another problem with my swapfile or with 6 :). Since you can compile a kernel without it, add DDB, WITNESS and INVARIANTS support, then trigger the deadlock with the swapfile, break to DDB and examine the state of the machine. See the chapter on kernel debugging in the developers handbook for more instructions. Thanks, but for now, I cannot compile a new kernel, because the kernel compilation terminates with insufficient swap space error. Apparently 32 MB is not enough for a new kernel compilation. So for now I'm stuck with the GENERIC kernel. This is my partitioning: /dev/ad0s1a253678 34446 19893815%/ /dev/ad0s1b 39848 8168 3984820%(swap) /dev/ad0s1d253678 152958 8042666%/var /dev/ad0s1e253678 6016 227368 3%/home /dev/ad0s1f 1624576 727274 76733649%/usr First I used 128 MB swapfile on root partition; then tried again with a 128 MB swapfile on /var. However, exactly the same deadlock occurs: when the kernel compilation reaches 'linking kernel' the PC is dead (no crash). Although I can ping the PC, there's no response to any other service; also serial port console is dead. Without using the swapfile, the compilation easily passes through the 'linking kernel' stage, but somewhat later terminates as swap space is insufficient. With 5-Stable, I used the swapfile extensively for recompiling new kernels and worlds, without any problem. I only can conclude that something is wrong with the swapfile construct in 6. Is 128 MB too big for a swapfile in 6? I'll try again with a smaller swapfile... Any other ideas? dmesg output of this PC is here: http://surfion.snu.ac.kr/~lahaye/dmesg Thanks, Rob. __ Yahoo! FareChase: Search multiple travel sites in one click. http://farechase.yahoo.com ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Swapfile problem in 6? (was: 6.0: during kernel compilation, 'kernel linking' freezes PC)
On Mon, 2005-Nov-14 22:38:59 -0800, Rob wrote: --- Kris Kennaway [EMAIL PROTECTED] wrote: Since you can compile a kernel without it, add DDB, WITNESS and INVARIANTS support, then trigger the deadlock with the swapfile, break to DDB and examine the state of the machine. See the chapter on kernel debugging in the developers handbook for more instructions. Thanks, but for now, I cannot compile a new kernel, because the kernel compilation terminates with insufficient swap space error. Unfortunately, we're probably not going to be able to provide much assistance without knowing more about what is happening when it deadlocks. (As Kris requests). BTW, you should probably make sure you keep makeoptions DEBUG=-g and set dumpdev in rc.conf (which will make it possible to capture and use a crashdump if you can trigger one). Apparently 32 MB is not enough for a new kernel compilation. Quite probably. This is my partitioning: /dev/ad0s1a253678 34446 19893815%/ /dev/ad0s1b 39848 8168 3984820%(swap) /dev/ad0s1d253678 152958 8042666%/var /dev/ad0s1e253678 6016 227368 3%/home /dev/ad0s1f 1624576 727274 76733649%/usr Since your /home is almost empty, how about (temporarily) moving the contents into /usr and swapping onto ad0s1e rather than into a swapfile. This should at least enable you to build a debug kernel. First I used 128 MB swapfile on root partition; then tried again with a 128 MB swapfile on /var. However, exactly the same deadlock occurs: Have you pre-allocated the swapfile or is it being allocated as necessary? If the latter, try dd if=/dev/zero of=swapfile bs=1m count=128 -- Peter Jeremy ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
