Thread (20 messages) 20 messages, 5 authors, 2021-10-01

Re: [PATCH v9 2/3] mm: add a field to store names for private anonymous memory

From: Pavel Machek <hidden>
Date: 2021-09-05 13:04:27
Also in: linux-fsdevel, linux-mm, lkml

Hi!
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
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.

								Pavel


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