Re: [PATCH] mm: Add AnonZero accounting for zero-filled anonymous pages

["David Hildenbrand (Arm)" <david@kernel.org>]

On 2/16/26 18:01, Matthew Wilcox wrote:
> On Mon, Feb 16, 2026 at 04:54:05PM +0000, Kiryl Shutsemau wrote:
>> What I would like to see in the kernel is a syscall that return the
>> memory stats in binary form. Something like
>>
>> size_t memstat(int pidfd, struct memstat memstatbuf[], size_t n,
>> 		unsigned long flags, unsigned long start, unsigned long end);
>>
>> The syscall will fill up to n memstatbufs, one per-VMA. What exactly
>> filled there defined by flags. The return value is how many memstatbuf
>> is populated. The caller can call it multiple times to walk address
>> space it is interested in.
>>
>> We also can have a flag that mirrors smaps_rollup behaviour and collect
>> all the data into a single memstatbuf.
> 
> But is that what we want?  Let's say a process allocates a 2MB THP, uses
> 12kB of it and then forks.
That's just like all of these entries (Rss, Anonymous, KSM) except the 
Pss ones behave.

-- 
Cheers,

David