mm: Add a .to_text() method for shrinkers

This adds a new callback method to shrinkers which they can use to
describe anything relevant to memory reclaim about their internal state,
for example object dirtyness.

This uses the new printbufs to output to heap allocated strings, so that
the .to_text() methods can be used both for messages logged to the
console, and also sysfs/debugfs.

This patch also adds shrinkers_to_text(), which reports on the top 10
shrinkers - by object count - in sorted order, to be used in OOM
reporting.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

0 files changed, 0 insertions, 0 deletions