17 Jun
2025
17 Jun
'25
11:01 p.m.
On Tue, Jun 17, 2025 at 02:23:41PM -0700, Nicolin Chen wrote:
On Tue, Jun 17, 2025 at 08:59:48AM -0300, Jason Gunthorpe wrote:
On Mon, Jun 16, 2025 at 07:02:08PM -0700, Nicolin Chen wrote:
---breakdown--- After `posix_memalign()`: [ posix_memalign() memory ] ← malloc thinks it owns this
Then `mmap(aligned_ptr, ..., MAP_FIXED)`: [ anonymous mmap region ] ← malloc still thinks it owns this (!) ↑ mapped ---end---
Yes, this is correct and what we are doing here. The allocator always owns it and we are just replacing the memory with a different mmap.
Hmm, if allocator always owns it. Does that mean the munmap() [3] will release what [1] and [2] do (allocating and replacing)?
No, munmap doesn't destroy the allocator meta data.
Jason