On Wed 06-10-21 11:18:31, Suren Baghdasaryan wrote:

On Wed, Oct 6, 2021 at 10:58 AM Pavel Machek [off-list ref] wrote:

[...]

quoted

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