Re: Fedora 34 Change: Scale ZRAM to Full Memory Size — arbitrary scaling
* Alexander Bokovoy:
This is a good note. If zram breaks kernel API promise to user space
(/proc/meminfo is one such API), how can it be enabled by default. I
also would question enabling zram by default if it does not play along
with cgroups. We do depend on cgroups being properly managed by systemd,
including resource allocation.
But that's impossible: The existing interfaces assume that there's no
RAM compression (or tiers of swap), so something has to give. As these
reported numbers are used for auto-sizing heaps and caches, there have
to be heuristics that happen to work for the majority of cases.
(Similar to what file systems do if they allocate inodes dynamically,
but still have to synthesize a reasonable-looking maximum to satisfy the
POSIX statvfs interface constraints.)
The alternative would be to come up with entirely new interfaces. The
container side of things did that, and from that perspective, anything
reading /proc/meminfo is already broken and needs to transition to the
new interfaces. But that
Thanks,
Florian
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