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gpa: Fix bookkeeping logic

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The backing allocator may return a block that's actually bigger than the
one required by the user, use the correct quantity when keeping track of
the allocation ceiling.

Closes #6049
This commit is contained in:
LemonBoy 2020-08-29 20:51:30 +02:00
parent 00301bbdd3
commit f20305d249
1 changed files with 27 additions and 25 deletions
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52
lib/std/heap/general_purpose_allocator.zig
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@ -567,38 +567,40 @@ pub fn GeneralPurposeAllocator(comptime config: Config) type {
const held = self.mutex.acquire();
defer held.release();
const prev_req_bytes = self.total_requested_bytes;
const new_aligned_size = math.max(len, ptr_align);
const mem_slice = blk: {
if (new_aligned_size > largest_bucket_object_size) {
try self.large_allocations.ensureCapacity(
self.backing_allocator,
self.large_allocations.entries.items.len + 1,
);
const slice = try self.backing_allocator.allocFn(self.backing_allocator, len, ptr_align, len_align, ret_addr);
const gop = self.large_allocations.getOrPutAssumeCapacity(@ptrToInt(slice.ptr));
assert(!gop.found_existing); // This would mean the kernel double-mapped pages.
gop.entry.value.bytes = slice;
collectStackTrace(ret_addr, &gop.entry.value.stack_addresses);
break :blk slice;
} else {
const new_size_class = math.ceilPowerOfTwoAssert(usize, new_aligned_size);
const ptr = try self.allocSlot(new_size_class, ret_addr);
break :blk ptr[0..len];
}
};
if (config.enable_memory_limit) {
const new_req_bytes = prev_req_bytes + len;
// The backing allocator may return a memory block bigger than
// `len`, use the effective size for bookkeeping purposes
const new_req_bytes = self.total_requested_bytes + mem_slice.len;
if (new_req_bytes > self.requested_memory_limit) {
return error.OutOfMemory;
}
self.total_requested_bytes = new_req_bytes;
}
errdefer if (config.enable_memory_limit) {
self.total_requested_bytes = prev_req_bytes;
};
const new_aligned_size = math.max(len, ptr_align);
if (new_aligned_size > largest_bucket_object_size) {
try self.large_allocations.ensureCapacity(
self.backing_allocator,
self.large_allocations.entries.items.len + 1,
);
const slice = try self.backing_allocator.allocFn(self.backing_allocator, len, ptr_align, len_align, ret_addr);
const gop = self.large_allocations.getOrPutAssumeCapacity(@ptrToInt(slice.ptr));
assert(!gop.found_existing); // This would mean the kernel double-mapped pages.
gop.entry.value.bytes = slice;
collectStackTrace(ret_addr, &gop.entry.value.stack_addresses);
return slice;
} else {
const new_size_class = math.ceilPowerOfTwoAssert(usize, new_aligned_size);
const ptr = try self.allocSlot(new_size_class, ret_addr);
return ptr[0..len];
}
return mem_slice;
}
fn createBucket(self: *Self, size_class: usize, bucket_index: usize) Error!*BucketHeader {