Hi, I'm hoping this is the right forum to ask the following question: libibverbs uses "madvise(MADV_DONTFORK)" on memory that was previously registered with "ib_reg_mr". With hugetlb support (environment variable "RDMAV_HUGEPAGES_SAFE" set), libibverbs parses "/proc/self/smaps" looking for the virtual-address in question to determine the proper page-size, ultimately calling "vma_kernel_pagesize" -> "hugetlb_vm_op_pagesize". Obviously, parsing "/proc/self/smaps" is rather slow with large processes that contain many VMAs. Question is: How to make this faster? One InfiniBand-specific way out is to create a sysfs entry, e.g. "/sys/class/infiniband_verbs/vma_pagesize" and provide an interface (e.g. ioctl) that gives libiverbs the same information, just a tad faster than parsing "/proc/self/smaps". But getting access to "vma_kernel_pagesize" is something that is hardly InfiniBand specific, and perhaps there are other applications/libraries out there (if not today, perhaps tomorrow) that would like to do the same. A generic interface from user-space to "vma_kernel_pagesize" (other than parsing /proc/self/smaps) could have potential benefit. But which API exactly? For that I'm seeking input from this forum. Thanks, Gerd
