std.heap: do not excessively call mmap, and munmap in direct allocator

This commit is contained in:
Shawn Landden 2019-04-09 10:48:09 -05:00 committed by Andrew Kelley
parent 8afa1e800b
commit 3c13aa178b

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@ -59,6 +59,8 @@ pub const DirectAllocator = struct {
fn alloc(allocator: *Allocator, n: usize, alignment: u29) error{OutOfMemory}![]u8 {
const self = @fieldParentPtr(DirectAllocator, "allocator", allocator);
if (n == 0)
return (([*]u8)(undefined))[0..0];
switch (builtin.os) {
Os.linux, Os.macosx, Os.ios, Os.freebsd, Os.netbsd => {
@ -140,7 +142,9 @@ pub const DirectAllocator = struct {
}
const result = try alloc(allocator, new_size, new_align);
@memcpy(result.ptr, old_mem.ptr, std.math.min(old_mem.len, result.len));
_ = os.posix.munmap(@ptrToInt(old_mem.ptr), old_mem.len);
if (old_mem.len > 0) {
_ = os.posix.munmap(@ptrToInt(old_mem.ptr), old_mem.len);
}
return result;
},
Os.windows => {