On Wed, Jan 30, 2013 at 01:39:23PM +0400, Mike Lykov wrote:
> 29.01.2013 19:33, Don Zickus пишет:
>
> >The softlockup mechanism works scheduling a high priority task that kicks
> >the softlockups. If the unzip thread is taking too long, it could
> >accidentally trip the detection.
>
> Inyerestingly, that a decompress of lzma -4 takes longer time than
> decompress lzma -9, and it stated in man lzma(1):
> " On the same hardware, the decompression speed is approximately
> a constant number of bytes of compressed data per second. In other
> words, the better the compression, the faster the decompression
> will usually be. "
>
> I tested it on target computer by hand:
>
> lzma -4 compressed: time unlzma initram-alt-p6rel3-4.cpio.lzma
> 20.94user 1.47system 0:22:45elapsed 99%CPU (...19424maxresidents)k
>
> lzma -9 compressed: time unlzma initram-alt-p6rel3-9.cpio.lzma
> 19.49user 1.92system 0:21:44elapsed 99%CPU (...241488maxresidents)k
>
> So, it cannot "take too long" because not-working faster than working.
> Apparently time not matter, but algorithm complexity?
>
> >>2. How to change watchdog_thresh parameter at boot without patching
> >>sources? If it necessary (with it side effects) maybe implement it
> >>as commandline parameter or config compile time parameter?
> >
> >I attached a patch below that allows you to set it a boot time. Let me
> >know if this works for you, then I can clean it up and post it properly.
>
> It not works for me. I apply this patch, build, use ("int
> __read_mostly watchdog_thresh = 10;" as in original)
> command line:
>
> [ 0.000000] Kernel command line:
> initrd=initram-alt-p6rel3-9.cpio.lzma console=uart,io,0x240,115200n8
> kernel.watchdog_thresh=30
I have never seen usage like 'kernel.watchdog_thresh=30'. Could you try
'watchdog_thresh=30' instead?
I also attached another patch as suggested by Andrew to add a
touch_softlockup_watchdog in the unlzma routine. Probably makes things
run a little slower. Compiled tested only.
Cheers,
Don
diff --git a/lib/decompress_unlzma.c b/lib/decompress_unlzma.c
index 32adb73..313f4fa 100644
--- a/lib/decompress_unlzma.c
+++ b/lib/decompress_unlzma.c
@@ -36,6 +36,7 @@
#endif /* STATIC */
#include <linux/decompress/mm.h>
+#include <linux/nmi.h>
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
@@ -648,6 +649,7 @@ STATIC inline int INIT unlzma(unsigned char *buf, int in_len,
}
if (rc.buffer_size <= 0)
goto exit_3;
+ touch_softlockup_watchdog();
}
if (posp)
--
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