This looks good to me with a small comment. > if (do_munmap(mm, old_addr, old_len, uf_unmap) < 0) { > /* OOM: unable to split vma, just get accounts right */ > - if (vm_flags & VM_ACCOUNT) > + if (vm_flags & VM_ACCOUNT && !(flags & MREMAP_DONTUNMAP)) > vm_acct_memory(new_len >> PAGE_SHIFT);
Checking MREMAP_DONTUNMAP in the do_munmap path is unnecessary as MREMAP_DONTUNMAP will have already returned by this point.