Kernel+Profiler: Make profiling per-process and without core dumps

This patch merges the profiling functionality in the kernel with the
performance events mechanism. A profiler sample is now just another
perf event, rather than a dedicated thing.

Since perf events were already per-process, this now makes profiling
per-process as well.

Processes with perf events would already write out a perfcore.PID file
to the current directory on death, but since we may want to profile
a process and then let it continue running, recorded perf events can
now be accessed at any time via /proc/PID/perf_events.

This patch also adds information about process memory regions to the
perfcore JSON format. This removes the need to supply a core dump to
the Profiler app for symbolication, and so the "profiler coredump"
mechanism is removed entirely.

There's still a hard limit of 4MB worth of perf events per process,
so this is by no means a perfect final design, but it's a nice step
forward for both simplicity and stability.

Fixes #4848
Fixes #4849

1 files changed, 3 insertions, 3 deletions

diff --git a/Kernel/Thread.cpp b/Kernel/Thread.cpp
index 8bb6664ff8..71283101f0 100644
--- a/Kernel/Thread.cpp
+++ b/Kernel/Thread.cpp
@@ -31,8 +31,8 @@
 #include <Kernel/Arch/i386/CPU.h>
 #include <Kernel/FileSystem/FileDescription.h>
 #include <Kernel/KSyms.h>
+#include <Kernel/PerformanceEventBuffer.h>
 #include <Kernel/Process.h>
-#include <Kernel/Profiling.h>
 #include <Kernel/Scheduler.h>
 #include <Kernel/Thread.h>
 #include <Kernel/ThreadTracer.h>
@@ -1036,7 +1036,7 @@ Vector<FlatPtr> Thread::raw_backtrace(FlatPtr ebp, FlatPtr eip) const
     InterruptDisabler disabler;
     auto& process = const_cast<Process&>(this->process());
     ProcessPagingScope paging_scope(process);
-    Vector<FlatPtr, Profiling::max_stack_frame_count> backtrace;
+    Vector<FlatPtr, PerformanceEvent::max_stack_frame_count> backtrace;
     backtrace.append(eip);
     FlatPtr stack_ptr_copy;
     FlatPtr stack_ptr = (FlatPtr)ebp;
@@ -1048,7 +1048,7 @@ Vector<FlatPtr> Thread::raw_backtrace(FlatPtr ebp, FlatPtr eip) const
         if (!safe_memcpy(&retaddr, (void*)(stack_ptr + sizeof(FlatPtr)), sizeof(FlatPtr), fault_at))
             break;
         backtrace.append(retaddr);
-        if (backtrace.size() == Profiling::max_stack_frame_count)
+        if (backtrace.size() == PerformanceEvent::max_stack_frame_count)
             break;
         stack_ptr = stack_ptr_copy;
     }