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Allow kernel with pagesize other than 4k on ARM #898

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Allow kernel with pagesize other than 4k on ARM #898

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9 changes: 5 additions & 4 deletions src/server.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6517,17 +6517,18 @@ int linuxMadvFreeForkBugCheck(void) {
int ret, pipefd[2];
pid_t pid;
char *p, *q, bug_found = 0;
const long map_size = 3 * 4096;
unsigned long page_size = sysconf(_SC_PAGESIZE);
const long map_size = 3 * page_size

/* Create a memory map that's in our full control (not one used by the allocator). */
p = (char*)mmap(NULL, map_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
serverAssert(p != MAP_FAILED);

q = p + 4096;
q = p + page_size;

/* Split the memory map in 3 pages by setting their protection as RO|RW|RO to prevent
* Linux from merging this memory map with adjacent VMAs. */
ret = mprotect(q, 4096, PROT_READ | PROT_WRITE);
ret = mprotect(q, page_size, PROT_READ | PROT_WRITE);
serverAssert(!ret);

/* Write to the page once to make it resident */
Expand All @@ -6537,7 +6538,7 @@ int linuxMadvFreeForkBugCheck(void) {
#ifndef MADV_FREE
#define MADV_FREE 8
#endif
ret = madvise(q, 4096, MADV_FREE);
ret = madvise(q, page_size, MADV_FREE);
serverAssert(!ret);

/* Write to the page after being marked for freeing, this is supposed to take
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