On Tue, Jun 17, 2025 at 08:01:36PM -0300, Jason Gunthorpe wrote: > 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.
Should we do something to that meta data?
