RFR: 8333522: JFR SwapSpace event might read wrong free swap space size [v3]

[Thomas Stuefe]

On Fri, 7 Jun 2024 11:52:22 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

> > > Feel free to do that. In a separate PR/bug though.
> > 
> > 
> > Thinking more about the potentially failing sysinfo - could it be that we get in this case an uninitialized sysinfo struct and just happily use the values from there ? For example here https://github.com/openjdk/jdk/blob/master/src/hotspot/os/linux/os_linux.cpp#L287
> 
> Yes. Seems so.

sysinfo, as far as I know, relies on /proc. Reading from /proc can theoretically fail. So, error handling would be good.

If you want to know if the observed errors stem from sysinfo failure, init the data structure, then, after the call, assert that the init values are overwritten.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/19574#issuecomment-2155996462