On Sat, May 04, 2024 at 01:24:23PM +0200, Christian Brauner wrote: > On Fri, May 03, 2024 at 05:30:01PM -0700, Andrii Nakryiko wrote: > > Implement binary ioctl()-based interface to /proc/<pid>/maps file to allow > > applications to query VMA information more efficiently than through textual > > processing of /proc/<pid>/maps contents. See patch #2 for the context, > > justification, and nuances of the API design. > > > > Patch #1 is a refactoring to keep VMA name logic determination in one place. > > Patch #2 is the meat of kernel-side API. > > Patch #3 just syncs UAPI header (linux/fs.h) into tools/include. > > Patch #4 adjusts BPF selftests logic that currently parses /proc/<pid>/maps to > > optionally use this new ioctl()-based API, if supported. > > Patch #5 implements a simple C tool to demonstrate intended efficient use (for > > both textual and binary interfaces) and allows benchmarking them. Patch itself > > also has performance numbers of a test based on one of the medium-sized > > internal applications taken from production. > > I don't have anything against adding a binary interface for this. But > it's somewhat odd to do ioctls based on /proc files. I wonder if there > isn't a more suitable place for this. prctl()? New vmstat() system call > using a pidfd/pid as reference? ioctl() on fs/pidfs.c? See my objection to the ioctl api in the patch review itself. Also, as this is a new user/kernel api, it needs loads of documentation (there was none), and probably also cc: linux-api, right? thanks, greg k-h
