Messages in this thread | | | Date | Sat, 25 Aug 2001 14:31:02 +1000 (EST) | From | Steve Kieu <> | Subject | Re: What version of the kernel fixes these VM issues? |
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--- Nicolas Pitre <nico@cam.org> wrote: > > > On Sat, 25 Aug 2001, Daniel Phillips wrote: > > > On August 24, 2001 10:12 pm, Nicolas Pitre wrote: > > > On Fri, 24 Aug 2001, Daniel Phillips wrote: > > > > > > > On August 24, 2001 08:14 pm, Nicolas Pitre > wrote: > > > > > I have a totally different setup but I can > reproduce the same behavior on > > > > > the system I have here: > > > > > > > > > > ARM board with 32 MB RAM, no cache, NFS > root. > > > > > The kernel is based on 2.4.8-ac9 plus some > small VM fixes from -ac10. > > > > > > > > > > My test consist in compiling gcc 3.0 while > some MP3s are continously playing > > > > > in the background. The gcc build goes > pretty far along until both the mp3 > > > > > player and the gcc build completely jam. > > > > > > > > Which sound system, and which sound card > driver? > > > > > > The driver is for the UDA1341 on a SA1110 chip > written by myself. It is > > > fully OSS compliant, no ALSA. > > > > Your system should be able to handle that easily. > Do you have some meminfo > > output to look at? What about 2.4.9? > > OK now I have some comparative data. Two kernels: > > 1) based on 2.4.8-ac9 + Riel's VM fixes from -ac10 > 2) based on 2.4.9 with no extra VM patches > > > The test: > ========= > > This board has 32MB RAM, no swap. Root fs is NFS. > On the serial console I > start a command line mp3 player. In a first telnet > session I start a build > of gcc 3.0 (./configure; make). In a second telnet > session I start 'top'. > Music plays while gcc builds and I can see the CPU > usage within top. > Pretty real scenario, real life situation, expected > system load, no trick.
Strange enough to me, I can not reproduce this with my computer nearly the same as your described situation
Except nfs root file system, I started several rxvt play mpg123 ; compile the kernel ; browsing the net using mozilla, running top at one rxvt, kernel uses 2.4.9 is fine; 2.4.6 is fine too.
My computer is 686 128Mb RAM only 72Mb swap
OOP, 2.4.9 applied the one small patch for VM fix (just one line > > 2.4.8-ac9 plus -ac10 VM fixes: > ============================== > > Everything looks fine for a while. But all of a > sudden: no more music, the > gcc build stalls, system looks dead. In my first > description of the problem > quoted above I said that the audio was spitting > glitches of 100 ms every 10 > secs or so. This time there is nothing. The only > difference is the > addition of 'top' in the process list. Even the > telnet sessions aren't > echoing keystrokes anymore. Only the serial console > echoes characters so > kernel BH's are still running. Sysrq on the serial > console works > fortunately. kswapd is looping like crazy: > > kswapd R C0023CC0 0 4 0 > 5 3 (L-TLB) > > At first NFS traffic occupied the full network > bandwidth to page stuff in. > But after a while the following was printed to the > console: > > nfs: task 41867 can't get a request slot > nfs: task 41868 can't get a request slot > nfs: task 41869 can't get a request slot > > and then no more NFS packet on the network. It is > possible to ping the box > which means that the net BH still works. > > A couple sysrq-P at random intervals shows the CPU > looping in the following > functions: > > PC value System.map > -------- ---------- > c0040d84 zone_inactive_plenty > c0041024 try_to_swap_out > c00216e0 cpu_sa1100_cache_clean_invalidate_range > c00216d0 cpu_sa1100_cache_clean_invalidate_range > c0041304 swap_out_mm > c0041168 swap_out_pmd > c0044324 __get_swap_page > c0040d60 zone_inactive_plenty > c0041128 swap_out_pmd > c0040fec try_to_swap_out > > Sysrq-M gives: > > SysRq : Show Memory > Mem-info: > Free pages: 1012kB ( 0kB HighMem) > ( Active: 2007, inactive_dirty: 0, inactive_clean: > 0, free: 253 (255 510 765) ) > 3*4kB 1*8kB 0*16kB 1*32kB 1*64kB 1*128kB 1*256kB > 1*512kB 0*1024kB 0*2048kB = 1012kB) > = 0kB) > = 0kB) > Swap cache: add 0, delete 0, find 0/0 > Free swap: 0kB > 8192 pages of RAM > 393 free pages > 636 reserved pages > 33 pages shared > 0 pages swap cached > 6 page tables cached > Buffer memory: 8000kB > > > 2.4.9 kernel: > ============= > > Unlike the first (quoted) run, this kernel > completely stalled when the jam > conditions were reached just like the run described > above. I mean here > there is no audio stuttering at all, no echo from > telnet sessions, nothing > in user space gets to run anymore. kswapd is well > locked in the R state: > > kswapd R C0022CA0 0 4 0 > 5 3 (L-TLB) > > Kernel interrupts and BHs still work i.e. I can ping > the box, the serial > console still echoes characters (kernel termios), > and sysrq works but that's > all. What's also interesting here is the fact that > there is absolutely no > NFS traffic going on. > > A couple sysrq-P at random intervals shows the CPU > looping in the following > functions: > > PC value System.map > -------- ---------- > c003f6e0 zone_inactive_plenty > c003fa58 swap_out_pmd > c0060324 prune_icache > c003f6fc zone_inactive_plenty > c003faac swap_out_pmd > c00209a0 cpu_sa1100_set_pte > c003fc80 swap_out_mm > c0040c10 refill_inactive_scan > c00206c0 cpu_sa1100_cache_clean_invalidate_range > c003fa90 swap_out_pmd > > Sysrq-M gives: > > SysRq: Show Memory > Mem-info: > Free pages: 1008kB ( 0kB HighMem) > ( Active: 2546, inactive_dirty: 63, inactive_clean: > 0, free: 252 (255 510 765) ) > 0*4kB 0*8kB 1*16kB 1*32kB 1*64kB 1*128kB 1*256kB > 1*512kB 0*1024kB 0*2048kB = 1008kB) > = 0kB) > = 0kB) > Swap cache: add 0, delete 0, find 0/0 > Free swap: 0kB > 8192 pages of RAM > 392 free pages > 602 reserved pages > 576 pages shared > 0 pages swap cached > 8 page tables cached > Buffer memory: 8000kB > > > Notes: > ====== > > - Both kernels go flat after approx 14 min of mp3 > playback. > - With enough retries (i.e. reboots) the gcc build > succeed, so there is no > lack of ressources in theory. > - SEnding a signal to the mp3 player (^C on the > serial === message truncated ===
===== S.KIEU
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