On Sun, Sep 5, 2021 at 6:04 AM Pavel Machek [off-list ref] wrote:

Hi!

quoted

quoted

the process is still running, so it has to have some sort of
synchronization with every layer of userspace.  Efficiently tracking
the ranges requires reimplementing something like the kernel vma
trees, and linking to it from every layer of userspace.  It requires
more memory, more syscalls, more runtime cost, and more complexity to
separately track regions that the kernel is already tracking.

Ok so far.

quoted

quoted

This patch adds a field to /proc/pid/maps and /proc/pid/smaps to show a
userspace-provided name for anonymous vmas.  The names of named anonymous
vmas are shown in /proc/pid/maps and /proc/pid/smaps as [anon:<name>].

Userspace can set the name for a region of memory by calling
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned
long)name);

Would setting a 64-bit integer instead of name be enough? Even if
each party would set it randomly, risk of collisions would be very
low... and we'd not have to deal with strings in kernel.

Thanks for the question, Pavel. I believe this was discussed in this
thread before and Colin provided the explanation with usage examples:
https://lore.kernel.org/linux-mm/20200821070552.GW2074@grain/ (local).
Thanks,
Suren.

                                                                Pavel


--

--
To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com.