hwpmc: fix leak of IBS per-CPU array on unloadHEADmain

pmc_ibs_initialize() allocates the ibs_pcpu[] pointer array, and
pmc_ibs_finalize() exists to free it, but pmc_ibs_finalize() is
never called.  Every hwpmc unload on a CPU with IBS therefore leaks
one pmc_cpu_max()-sized pointer array.

Call pmc_ibs_finalize() from pmc_amd_finalize(), alongside the RAPL,
TSC and perf classes.  IBS is only initialized on CPUs that support
it, so make pmc_ibs_finalize() return early when ibs_pcpu is NULL,
making it safe to call when the class was skipped at initialize
time, as pmc_rapl_finalize() already is.

Tested on an AMD Ryzen 5 5600X (Zen 3, 12 threads) with INVARIANTS.
Before the change, each kldload/kldunload cycle leaked one 96-byte
M_PMC allocation, and DTrace showed the ibs_pcpu[] allocation from
pmc_ibs_initialize() as the only one never freed.  After the change,
50 load/unload cycles leave M_PMC InUse and MemUse unchanged, and
every allocation made at load is freed at unload.

Reviewed by:	mhorne
Fixes:		e51ef8ae490f ("hwpmc: Initial support for AMD IBS")
Sponsored by:	NLINK (https://nlink.com.br), Recife, Brazil
Differential Revision:	https://reviews.freebsd.org/D59881

0 files changed, 0 insertions, 0 deletions