Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat

On Fri, 27 Apr 2018, Vlastimil Babka wrote:

It was in the original thread, see e.g.
[ref]

However it will take some time to get that in mainline, and meanwhile
the current implementation does prevent a DOS. So I doubt it can be
fully reverted - as a compromise I just didn't want the counter to
become ABI. TBH though, other people at LSF/MM didn't seem concerned
that /proc/vmstat is an ABI that we can't change (i.e. counters have
been presumably removed in the past already).

What prevents this from being a simple atomic_t that gets added to in 
__d_alloc(), subtracted from in __d_free_external_name(), and read in 
si_mem_available() and __vm_enough_memory()?