procfs_map does a very naive resident count, which for huge unbacked virtual spaces takes essentially forever. Instead of trying to fix this (see bug 188911), the resident count field should be deprecated and always be set to 0. Linux procfs does not return resident counts.
I think it is better to use the already existing optimized algorithm, also honoring the sysctl to enable/disable the residency calculation. Please see D13595.
A commit references this bug: Author: kib Date: Thu Dec 28 13:23:13 UTC 2017 New revision: 327286 URL: https://svnweb.freebsd.org/changeset/base/327286 Log: Reuse kern_proc_vmmap_resident() for procfs_map resident count. The existing algorithm in procfs_map() to calculate count of resident pages in an entry is too primitive, resulting in too long run time for large sparse mapping entries. Re-use the kern_proc_vmmap_resident() from kern_proc.c which only looks at the existing pages in the iterations. Also, this makes procfs to honor kern.proc_vmmap_skip_resident_count, if user does not need this information. Reported by: Glenn Weinberg <glenn.weinberg@intel.com> PR: 224532 No objections from: des (procfs maintainer) Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D13595 Changes: head/sys/fs/procfs/procfs_map.c
For bugs matching the following conditions: - Status == In Progress - Assignee == "bugs@FreeBSD.org" - Last Modified Year <= 2017 Do - Set Status to "Open"
I think all supported releases have this change.