From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Daniel Micay Date: Sat, 19 Nov 2016 09:56:14 -0500 Subject: [PATCH] stop implicitly marking mappings as mergeable Signed-off-by: anupritaisno1 --- libc/bionic/mmap.cpp | 19 +------------------ 1 file changed, 1 insertion(+), 18 deletions(-) diff --git a/libc/bionic/mmap.cpp b/libc/bionic/mmap.cpp index 9aad0b315..6bf0ecfd1 100644 --- a/libc/bionic/mmap.cpp +++ b/libc/bionic/mmap.cpp @@ -39,8 +39,6 @@ extern "C" void* __mmap2(void*, size_t, int, int, int, size_t); #define MMAP2_SHIFT 12 // 2**12 == 4096 -static bool kernel_has_MADV_MERGEABLE = true; - void* mmap64(void* addr, size_t size, int prot, int flags, int fd, off64_t offset) { if (offset < 0 || (offset & ((1UL << MMAP2_SHIFT)-1)) != 0) { errno = EINVAL; @@ -54,22 +52,7 @@ void* mmap64(void* addr, size_t size, int prot, int flags, int fd, off64_t offse return MAP_FAILED; } - bool is_private_anonymous = - (flags & (MAP_PRIVATE | MAP_ANONYMOUS)) == (MAP_PRIVATE | MAP_ANONYMOUS); - bool is_stack_or_grows_down = (flags & (MAP_STACK | MAP_GROWSDOWN)) != 0; - - void* result = __mmap2(addr, size, prot, flags, fd, offset >> MMAP2_SHIFT); - - if (result != MAP_FAILED && kernel_has_MADV_MERGEABLE && - is_private_anonymous && !is_stack_or_grows_down) { - ErrnoRestorer errno_restorer; - int rc = madvise(result, size, MADV_MERGEABLE); - if (rc == -1 && errno == EINVAL) { - kernel_has_MADV_MERGEABLE = false; - } - } - - return result; + return __mmap2(addr, size, prot, flags, fd, offset >> MMAP2_SHIFT); } void* mmap(void* addr, size_t size, int prot, int flags, int fd, off_t offset) {