Re: [PATCH v10 3/3] mm: add anonymous vma name refcounting

[Michal Hocko]

On Wed 06-10-21 11:18:31, Suren Baghdasaryan wrote:
> On Wed, Oct 6, 2021 at 10:58 AM Pavel Machek <pavel@xxxxxx> wrote:
[...]
> > That "central facility" option can be as simple as "mkdir
> > /somewhere/sanitized_id", using inode numbers for example. You don't
> > really need IPC.
> 
> Hmm, so the suggestion is to have some directory which contains files
> representing IDs, each containing the string name of the associated
> vma? Then let's say we are creating a new VMA and want to name it. We
> would have to scan that directory, check all files and see if any of
> them contain the name we want to reuse the same ID.

I believe Pavel meant something as simple as
$ YOUR_FILE=$YOUR_IDS_DIR/my_string_name
$ touch $YOUR_FILE
$ stat -c %i $YOUR_FILE

YOUR_IDS_DIR can live on a tmpfs and you can even implement a policy on
top of that (who can generate new ids, gurantee uniqness etc...).

The above is certainly not for free of course but if you really need a
system wide consistency when using names then you need some sort of
central authority. How you implement that is not all that important
but I do not think we want to handle that in the kernel.
-- 
Michal Hocko
SUSE Labs