[systemd-devel] Significant performance loss caused by commit a65f06b: journal: return -ECHILD after a fork

[Uoti Urpala]

Resend with correct list address
On Tue, 2017-07-11 at 12:00 +0200, Lennart Poettering wrote:
> On Tue, 11.07.17 12:55, Uoti Urpala (uoti.urpala at pp1.inet.fi) wrote:
> > Are you sure about those "Debian only" and "will be 'fixed'" parts? The
> > Debian patch seems to be a cherry pick from upstream glibc. Is there
> > evidence of some error that would cause effects only visible on Debian
> > and nowhere else? And/or has the change been reverted or behavior
> > otherwise modified upstream to limit the range of relevant versions?
> 
> See the links Vito provided:
> 
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=857909
> https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commit;h=0cb313f7cb0e418b3d56f3a2ac69790522ab825d
> 
> i.e. Debian undid the PID caching to fix some issue that has been fix
> properly now, and hence the PID caching should be turned on again.

That seems backwards: the commit cherry-picked by Debian seems to be
c579f48edba88380635a, which is NEWER than above 0cb313f7cb0e418b3d56.
In other words, it seems 0cb313 was a failed attempt at a fix and the
patch cherry-picked by Debian was needed to properly fix things.

> On Fedora at least getpid() is not visible in strace, and is fully
> cached, as it should be.

Is that glibc 2.25? It seems to contain c579f48 at least; could be a
Fedora-specific change though?