Messages in this thread |  | | | Subject | Re: more info on dcache corruption in 2.1.76 [now 2.1.78] | | Date | Thu, 08 Jan 1998 08:39:13 -0800 | | From | Ben Woodard <> |
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I have upgraded to 2.1.78 and the same problem with the dcache becoming corrupt is occuring. However, a pattern may be beginning to emerge. It is kind of interesting it is as though I was looking in the wrong direction all this time. I was looking at the programs that I was running and what they were doing just before the problem in the dcache appeared. But every time, what was going on with the computer was completely different. What I didn't realize was that it was happening about the same time each day or there abouts and I am beginning to think that this is the key to the problem and why I manifest it so regularly.
See each day, I get up go to work and while at work, I am really in multitask mode. I am doing a dozen things at once. I have lots of applications open and lots of windows on my computer doing things. Then I take my computer home and read email and mess around with things. Completely different enviornment. I have very few windows open and I am focusing on basically one thing for a long period of time. It is during these times that the dcache becomes corrupt. It has never happened while I am at work and my computer is under load but happens to me almost every night after I have simplified my environment quite a bit.
The thing that occured to me is my virtual memory usage while at work is signifcantly higher. Now if I understand it correctly, linux uses all available memory for its purposes and so competes with applications for memory. Now at work the kernel is probably on the loosing side and the size of the caches such as the dcache are probably kind of small. However, when I go home I close down a huge number of windows and a bunch of applications and so the pool of memory available for things like the dcache expands. It occurs to me that might be where the problem is, in the code that grows the dcache.
My regular fluctuations in memory probably are what is making the bug appear so regularly and if as I suspect the problem is tied to the size of kernel mem available for the dcache that would also explain the time lag between when I shut down all my apps when leaving work and the time that the problem in the dcache appears.
It appears to me that there are several places in the dcache code where memory usage information is printk'd but they are all bracketed by #ifdef DCACHE_DEBUG's. I believe that I am going to define that see if I can see any pattern in the usage of dcache memory and this bug. If you can think of any other places where I should put printk's let me know. I'm sorry, I am not more help. I am just beginning to look around in the kernel and the dcache seems like a fairly complicated structure and I have yet to fully understand it.
Hope this informatin helps, -ben
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