Messages in this thread | | | From | (Eric W. Biederman) | Subject | Re: PID entries in /proc sorted by number, not start time in 2.6.19 | Date | Wed, 28 Feb 2007 16:39:43 -0700 |
| |
Chuck Ebbert <cebbert@redhat.com> writes:
> Starting with kernel 2.6.19, the process directories in > /proc are sorted by number. They were sorted by process > start time in 2.6.18 and earlier. This makes the output > of procps come out in that order too, pissing off users > who are used to the old way. > > To reproduce: > 1. Wrap your PID numbers. > 2. Do ls -fl /proc > 3. Look at output of ps command. > > Compare 2.6.18 to 2.6.19. > > See also: > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=230227
Apologies, but this was a bug fix for a more serious issue. The code to report the directory entries by start time was fundamentally broken. In particular the sequence: opendir readdir readdir readdir .... closedir
can miss processes that exist for the entire duration of that sequence. Which is non-posix, non-intuitive, and has no reasonable work around.
The sorting by pid happened as a side effect of finding a stable token we can come back to so we can at least guarantee normal readdir semantics. That objects that exist for the entire readdir are guaranteed to be displayed. That objects that come into existence or are deleted during the readdir may be missed. That isn't perfect but it is a useable semantic.
Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |