Hi,
David Miller wrote: [Mon Sep 30 2013, 12:31:30PM EDT]
>
> This is a respin of the original page_offset and 64-bit page
> table changes with some minor changes and a bug fix:
>
> 1) Bob's ACKs for the first 6 patches added.
>
> 2) Don't use "UL" postfix for shift counts, there is code that
> wants those to be "int", particularly printfs in mm/mm_init.c
> that use the "%d" format specifier for SECTIONS_SHIFT.
>
> 3) Adjust VA_HOLE defines to match what the new 3-level page
> tables can actually provide.
>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
We seem to have our first issue with THP.
I first encountered it with "ld". A THP enabled value of "never" resolved the
issue.
Verified no issue on four level page table. Also no issue on x86_64 with
3.7.x and 3.11 with unmodified test code.
I've reviewed most of TT 0x31 paths. I commenced moving up in mm layer.
Of course the debug code could have a bug :) I did examine some strace
output to check posix_memalign but not the glibc source.
It is Debian Wheezy and compiled with -m64. This on the T4-2 local to me.
The issue appears to be corruption.
thanx,
bob
<<CLIP HERE>>
#define _GNU_SOURCE
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/mman.h>
#ifndef MADV_HUGEPAGE
#define MADV_HUGEPAGE 14
#endif
#define HPAGE_SHIFT (22UL)
#define HPAGE_SIZE (1UL << HPAGE_SHIFT)
#define PAGE_SHIFT (13UL)
#define NR_PAGES_HPAGE (HPAGE_SIZE >> PAGE_SHIFT)
#define __round_mask(x, y) ((__typeof__(x))((y)-1))
#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
/* Note failure assumes an exit(1).
*/
void *allocate_thps(size_t sz)
{
int rc;
void *addr;
size_t align = HPAGE_SIZE;
rc = posix_memalign(&addr, align, sz);
if (rc)
perror("posix_memalign"), exit(1);
rc = madvise(addr, sz, MADV_HUGEPAGE);
if (rc)
perror("madvise"), exit(1);
return addr;
}
/* Verify the array.
*/
static void verify_thp(void *addr, void *end, int pagesize, int cnt)
{
unsigned long pc;
void *p;
for (pc = 0, p = addr; p < end; p += pagesize, pc++) {
if (*(unsigned long *) p != 0xbeefUL + (pc << 32UL)) {
fprintf(stderr, "\n\tcnt = %d pc=0x%lx thp = 0x%lx "
" addr=0x%lx *addr=0x%lx\n",
cnt, pc, pc >> 9UL, p, *(unsigned long *) p);
pc = (pc + NR_PAGES_HPAGE) & ~(NR_PAGES_HPAGE - 1);
pc--;
p = addr + (pc << PAGE_SHIFT);
}
}
}
int main(int argc, char **argv)
{
void *addr, *end, *p;
size_t sz;
int pagesize = getpagesize();
int loop, cnt, nthp, rc;
int recycle = 1;
unsigned long pc;
int optind = 0;
if (argc == 4 && argv[1][1] == 'a')
optind = 1;
else if (argc != 3)
fprintf(stderr, "%s: -a iterations 4Mb-pages\n",
argv[0]), exit(1);
rc = sscanf(argv[optind + 1], "%d", &loop);
if (rc != 1)
fprintf(stderr, "%s: sscanf (%s) failed\n",
argv[0], argv[optind + 1]), exit(1);
rc = sscanf(argv[optind + 2], "%d", &nthp);
if (rc != 1)
fprintf(stderr, "%s: sscanf (%s) failed\n",
argv[0], argv[optind + 2]), exit(1);
if (optind)
recycle = 0;
sz = HPAGE_SIZE * nthp;
for (cnt = 0; cnt < loop; cnt++) {
addr = allocate_thps(sz);
end = addr + sz;
fprintf(stderr, "[0x%lx-0x%lx) ",
(unsigned long) addr, (unsigned long) end);
for (pc = 0, p = addr; p < end; p += pagesize, pc++)
*(unsigned long *) p = 0xbeefUL + (pc << 32UL);
verify_thp(addr, end, pagesize, cnt);
sleep(cnt % 5);
verify_thp(addr, end, pagesize, cnt);
if (recycle)
free(addr);
fprintf(stdout, ".\n");
fflush(stdout);
}
fprintf(stderr, "%s: Done! cnt = %d\n", argv[0], cnt);
return 0;
}
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