Messages in this thread | | | Date | Thu, 14 Feb 2002 20:51:06 -0800 | From | William Lee Irwin III <> | Subject | [TEST] page tables filling non-highmem |
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The following testcase brought down 2.4.17 mainline on an 8-way P-III 700MHz machine with 12GB of RAM. The last thing logged from it was a LowFree of 2MB with 9GB of highmem free after something like 6-8 hours of pounding away, at which time the machine stopped responding (IIRC it was given ~12 hours to echo another character).
This testcase is a blatant attempt to fill the direct-mapped portion of the kernel virtual address space with process pagetables. It was suspected such a thing was happening in another failure scenario which is what motivated me to devise this testcase. I believe a fix already exists (i.e. aa's ptes in highmem stuff) though I've not yet verified its correct operation here.
The driver script was this:
#!/bin/sh for n in `seq 0 1023` do ./death & done
and the C program was the following:
#define __USE_LARGEFILE64 #include <stdio.h> #include <unistd.h> #include <sys/mman.h> #include <sys/stat.h> #include <sys/types.h> #define __USE_LARGEFILE64 #include <fcntl.h> #include <errno.h>
#define MAPPING_START 0x20000000 #define MAPPING_SIZE (0x80000000/sizeof(unsigned long)) #define MAPPING_END (MAPPING_START + MAPPING_SIZE*sizeof(unsigned long))
int main(void) { int fd; unsigned long *data = NULL; unsigned long try = 64; unsigned long k = 0;
fd = open("/home/wli/bench/mapfile", O_RDWR|O_LARGEFILE);
if (fd < 0) { perror("death"); printf("could not open mapfile!\n"); exit(1); }
data = mmap((void *)MAPPING_START, MAPPING_SIZE, PROT_READ|PROT_WRITE, MAP_FIXED | MAP_SHARED, fd, 0);
if (!try || data == MAP_FAILED) { printf("mmap() failed, tries = %lu!\n", 64 - try + 1); exit(1); }
printf("managed to mmap() at %p\n", (void *)data);
sleep(60);
try = 0; while (1) { printf("entered iteration %lu\n", k); data[k++] = try++; k %= MAPPING_SIZE; if (k >= MAPPING_SIZE-1) k = 0; } return 0; }
Cheers, Bill - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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