Memory increase using glibc - 2.35

[Szabolcs Nagy]

The 02/07/2023 09:21, Ronny Meeus via Libc-help wrote:
> we recently did an upstep to glibc-2.35 (from glibc-2.34) and we
> observed a substantial memory increase in 1 application.
> Our embedded SW is running on Linux 4.1.52 on ARM CPUs and consists of
> many applications.
> 
> All apps, except 1, are consuming more or less the same amount of memory.
> Note that these apps are executing a malloc_trim periodically (no clue
> whether that has something to do with it).
> For the problematic application (which is not executing malloc_trim),
> the memory consumption increased from 250Mb to 300Mb, with the same
> configuration.
> 
> We did already a "pmap" of the both apps and the observation is that
> there are a lot more (and bigger in size) anon pages allocated when
> running 2.35.
> The complete increase of 50Mb can be traced back to the increase of these pages.
> 
> Can this be explained by one of the changes in 2.35?
> We are not using any tuneables.

the 2.35 development window was between 2021-08-01 and 2022-02-01.
there were malloc changes, maybe the huge page support had some sideeffect:
https://sourceware.org/git/?p=glibc.git;a=history;f=malloc;hb=refs/tags/glibc-2.35

you may have to bisect this.