[Bug gdb/23505] New: index cache: Have a size limit

[simon.marchi at ericsson dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=23505

Bug ID: 23505
Summary: index cache: Have a size limit
Product: gdb
Version: HEAD
Status: NEW
Severity: normal
Priority: P2
Component: gdb
Assignee: unassigned at sourceware dot org
Reporter: simon.marchi at ericsson dot com
Target Milestone: ---

The index cache saves files but never deletes them. As a result, it will only
grow over time. We should have a size limit and make GDB delete old index
files when the total size of the cache would go over this limit.

This needs to work relatively correctly when multiple GDB do the cleanup
concurrently. I say relatively, because the important thing is the GDBs don't
crash and continue to produce good results. It doesn't matter if we go a
little bit over the space limit sometimes because of a race condition in the
computing of the used space.