8 Jul
2021
8 Jul
'21
12:46 p.m.
On Wed, Jul 07, 2021 at 08:50:51PM +0000, Michael Kjörling wrote:
On 7 Jul 2021 20:32 +0200, from rtomek(a)ceti.pl (Tomasz
Rola):
This is quite strange for me. Without looking at your system I can only
suspect it has something to do with multithreading.
If I do two different commands as root, with firefox pid here
.eq. 12331, as above:
=> (500 15): lsof -p 12331 | wc -l
402
=> (500 17): lsof | awk '$2==12331' | wc -l
22055
The first column gives a name, and in second case it not always is
'firefox'. I am yet to study manpage for lsof and play with it, but it
surely shows interesting things.
On my system, when firefox gets killed, 'free' shows a difference - if
I recall, free mem increases by the size of rss plus all the stuff
which was opened and released from buffers. I did not pay much
attention, I assumed numbers would match and this is what they
probably did :-).
OS on my box used to report to me as Debian, and still does, but some
years ago I have decided to skip the usual system upgrade, and after
some more time I started to upgrade various elements by hand. So it is
more like a tattered patchwork right now. But it does what I expect,
hopefully.
[...]
An excerpt from my ps:
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
xxxon 12331 12.5 20.4 5898360 2519640 ? TNsl Mar29 18278:11 firefox-esr
I'm going to stick my neck out here by saying that the VSZ and RSS
values reported by ps, at least for Firefox, are largely meaningless.
I started my usual Firefox instance, which has a handful of plugins,
about a metric gazillion bookmarks, and has been my main web browser
profile for years (so it probably has collected some crud over time).
`ps auxw` reported that process as having a total RSS of a whopping
374 GB.
It is downright _impossible_ that Firefox could actually be using that That's a _factor almost 2300x_ difference between
the reported RSS,
and the amount of memory that was actually freed up by closing the
browser.
Yeah, strange.
[...]
On modern systems, with everything from shared
libraries to
memory-mapped I/O to routine use of memory overcommitting, the
resident set size is clearly a poor indicator of the actual amount
of memory actively used by a complex process.
Hard to tell - first I would like to learn where the hundred-giga rss
came from...
--
Regards,
Tomasz Rola
--
** A C programmer asked whether computer had Buddha's nature. **
** As the answer, master did "rm -rif" on the programmer's home **
** directory. And then the C programmer became enlightened... **
** **
** Tomasz Rola mailto:tomasz_rola@bigfoot.com **