From: Waldemar Kozaczuk <jwkozac...@gmail.com>
Committer: Waldemar Kozaczuk <jwkozac...@gmail.com>
Branch: master
lazy stack: new tracepoint for stack pre-faults
This last patch of the series adds new tracepoint - mmu_vm_stack_fault -
which when enabled allows one to see how particular app triggers
the stack page faults. The tracepoint captures the stack fault address,
the thread id and number of the page (0 being the 1st page).
Please note this does not capture the 1st page of the stack (page_no 0) as this
one
pre-faulted by the parent thread that creates a new one.
./scripts/run.py -e /tests/tst-pipe.so --trace=mmu_vm_stack_fault
--trace-backtrace -H
./scripts/trace.py extract && ./scripts/trace.py list -bl
0xffff8000016b7040 >init 0 0.002215401 mmu_vm_stack_fault
thread=32, addr=0x00002000000ff9d0, page_no=1
mmu::vm_fault(unsigned long, exception_frame*)
page_fault
ex_pf
std_malloc(unsigned long, unsigned long)
malloc
operator new(unsigned long)
do_main_thread(void*)
std::_Function_handler<void (), pthread_private::pthread::pthread(void*
(*)(void*), void*, sigset_t, pthread_private::thread_attr
const*)::{lambda()#1}>::_M_invoke(std::_Any_data const&) __invoke_impl<void,
pthread_private::pthread::pthread(void* (*)(void*), void*, sigset_t, const
pthread_private::thread_attr*)::<lambda()>&>__invoke_r<void,
pthread_private::pthread::pthread(void* (*)(void*), void*, sigset_t, const
pthread_private::thread_attr*)::<lambda()>&> _M_invoke
sched::thread::main()
thread_main_c
...
0xffff8000016b7040 >init 0 0.084799151 mmu_vm_stack_fault
thread=32, addr=0x00002000000f8440, page_no=8
mmu::vm_fault(unsigned long, exception_frame*)
page_fault
ex_pf
memory::page_pool::l1::alloc_page()
untracked_alloc_page
memory::alloc_page()
std_malloc(unsigned long, unsigned long)
malloc
operator new(unsigned long)
lookup
sys_lstat
Signed-off-by: Waldemar Kozaczuk <jwkozac...@gmail.com>
---
diff --git a/core/mmu.cc b/core/mmu.cc
--- a/core/mmu.cc
+++ b/core/mmu.cc
@@ -1413,6 +1413,9 @@ bool access_fault(vma& vma, unsigned int error_code)
TRACEPOINT(trace_mmu_vm_fault, "addr=%p, error_code=%x", uintptr_t, unsigned
int);
TRACEPOINT(trace_mmu_vm_fault_sigsegv, "addr=%p, error_code=%x, %s",
uintptr_t, unsigned int, const char*);
TRACEPOINT(trace_mmu_vm_fault_ret, "addr=%p, error_code=%x", uintptr_t,
unsigned int);
+#if CONF_lazy_stack
+TRACEPOINT(trace_mmu_vm_stack_fault, "thread=%d, addr=%p, page_no=%d",
unsigned int, uintptr_t, unsigned int);
+#endif
static void vm_sigsegv(uintptr_t addr, exception_frame* ef)
{
@@ -1438,6 +1441,14 @@ void vm_fault(uintptr_t addr, exception_frame* ef)
trace_mmu_vm_fault_sigsegv(addr, ef->get_error(), "fast");
return;
}
+#if CONF_lazy_stack
+ auto stack = sched::thread::current()->get_stack_info();
+ void *v_addr = reinterpret_cast<void*>(addr);
+ if (v_addr >= stack.begin && v_addr < stack.begin + stack.size) {
+ trace_mmu_vm_stack_fault(sched::thread::current()->id(), addr,
+ ((u64)(stack.begin + stack.size - addr)) / 4096);
+ }
+#endif
addr = align_down(addr, mmu::page_size);
WITH_LOCK(vma_list_mutex.for_read()) {
auto vma = find_intersecting_vma(addr);
--
You received this message because you are subscribed to the Google Groups "OSv
Development" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to osv-dev+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/osv-dev/000000000000cdb7c005eb296ba3%40google.com.
