ANDROID: mm: add vh for kcompactd_cpu_online()

kcompactd_cpu_online() changes kcompactd cpumask, potentially
overwriting any vendor-specific cpumask that was there. This
hook allows vendors to re-set the cpumask.

Bug: 367400751
Signed-off-by: Dmitry Skiba <dskiba@google.com>
(cherry picked from commit b3a2458fc6e6bf265ee52297f6478e4b43725fb2)
Signed-off-by: Jacky Liu <qsliu@google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:9a46e8ecf74c33f25dad1d6ad6592cdfc530c02e)
Change-Id: I45b92bcd16fbf2d5d76474287db659e32af64201

drivers/android/vendor_hooks.c

@@ -436,3 +436,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_mm_compaction_end);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_vmscan_kswapd_wake);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_vmscan_kswapd_done);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_customize_alloc_gfp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_mm_kcompactd_cpu_online);

include/trace/hooks/mm.h

@@ -384,6 +384,9 @@ DECLARE_HOOK(android_vh_adjust_kvmalloc_flags,
 DECLARE_HOOK(android_vh_customize_alloc_gfp,
 	TP_PROTO(gfp_t *alloc_gfp, unsigned int order),
 	TP_ARGS(alloc_gfp, order));
+DECLARE_HOOK(android_vh_mm_kcompactd_cpu_online,
+	TP_PROTO(int cpu),
+	TP_ARGS(cpu));
 
 #endif /* _TRACE_HOOK_MM_H */
 

mm/compaction.c

@@ -3336,6 +3336,7 @@ static int kcompactd_cpu_online(unsigned int cpu)
 			if (pgdat->kcompactd)
 				set_cpus_allowed_ptr(pgdat->kcompactd, mask);
 	}
+	trace_android_vh_mm_kcompactd_cpu_online(cpu);
 	return 0;
 }