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[Qemu-devel] [PATCH V8 5/6] oslib-posix: add a configure switch to debug
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCH V8 5/6] oslib-posix: add a configure switch to debug stack usage |
Date: |
Mon, 26 Sep 2016 13:44:31 +0200 |
this adds a knob to track the maximum stack usage of stacks
created by qemu_alloc_stack.
Signed-off-by: Peter Lieven <address@hidden>
---
configure | 19 +++++++++++++++++++
util/oslib-posix.c | 40 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 58 insertions(+), 1 deletion(-)
diff --git a/configure b/configure
index 8fa62ad..93ef00a 100755
--- a/configure
+++ b/configure
@@ -296,6 +296,7 @@ libiscsi=""
libnfs=""
coroutine=""
coroutine_pool=""
+debug_stack_usage="no"
seccomp=""
glusterfs=""
glusterfs_xlator_opt="no"
@@ -1004,6 +1005,8 @@ for opt do
;;
--enable-coroutine-pool) coroutine_pool="yes"
;;
+ --enable-debug-stack-usage) debug_stack_usage="yes"
+ ;;
--disable-docs) docs="no"
;;
--enable-docs) docs="yes"
@@ -4276,6 +4279,17 @@ if test "$coroutine" = "gthread" -a "$coroutine_pool" =
"yes"; then
error_exit "'gthread' coroutine backend does not support pool (use
--disable-coroutine-pool)"
fi
+if test "$debug_stack_usage" = "yes"; then
+ if test "$cpu" = "ia64" -o "$cpu" = "hppa"; then
+ error_exit "stack usage debugging is not supported for $cpu"
+ fi
+ if test "$coroutine_pool" = "yes"; then
+ echo "WARN: disabling coroutine pool for stack usage debugging"
+ coroutine_pool=no
+ fi
+fi
+
+
##########################################
# check if we have open_by_handle_at
@@ -4861,6 +4875,7 @@ echo "QGA MSI support $guest_agent_msi"
echo "seccomp support $seccomp"
echo "coroutine backend $coroutine"
echo "coroutine pool $coroutine_pool"
+echo "debug stack usage $debug_stack_usage"
echo "GlusterFS support $glusterfs"
echo "Archipelago support $archipelago"
echo "gcov $gcov_tool"
@@ -5330,6 +5345,10 @@ else
echo "CONFIG_COROUTINE_POOL=0" >> $config_host_mak
fi
+if test "$debug_stack_usage" = "yes" ; then
+ echo "CONFIG_DEBUG_STACK_USAGE=y" >> $config_host_mak
+fi
+
if test "$open_by_handle_at" = "yes" ; then
echo "CONFIG_OPEN_BY_HANDLE=y" >> $config_host_mak
fi
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 7d053b8..18940d9 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -50,6 +50,10 @@
#include "qemu/mmap-alloc.h"
+#ifdef CONFIG_DEBUG_STACK_USAGE
+#include "qemu/error-report.h"
+#endif
+
int qemu_get_thread_id(void)
{
#if defined(__linux__)
@@ -503,6 +507,9 @@ pid_t qemu_fork(Error **errp)
void *qemu_alloc_stack(size_t *sz)
{
void *ptr, *guardpage;
+#ifdef CONFIG_DEBUG_STACK_USAGE
+ void *ptr2;
+#endif
size_t pagesz = getpagesize();
size_t allocsz;
#ifdef _SC_THREAD_STACK_MIN
@@ -535,10 +542,41 @@ void *qemu_alloc_stack(size_t *sz)
abort();
}
+#ifdef CONFIG_DEBUG_STACK_USAGE
+ for (ptr2 = ptr + pagesz; ptr2 < ptr + allocsz; ptr2 += sizeof(uint32_t)) {
+ *(uint32_t *)ptr2 = 0xdeadbeaf;
+ }
+#endif
+
return ptr;
}
+#ifdef CONFIG_DEBUG_STACK_USAGE
+static __thread unsigned int max_stack_usage;
+#endif
+
void qemu_free_stack(void *stack, size_t sz)
{
- munmap(stack, sz + getpagesize());
+#ifdef CONFIG_DEBUG_STACK_USAGE
+ unsigned int usage;
+ void *ptr;
+#endif
+ size_t pagesz = getpagesize();
+ size_t allocsz = sz + pagesz;
+
+#ifdef CONFIG_DEBUG_STACK_USAGE
+ for (ptr = stack + pagesz; ptr < stack + allocsz; ptr += sizeof(uint32_t))
{
+ if (*(uint32_t *)ptr != 0xdeadbeaf) {
+ break;
+ }
+ }
+ usage = sz - (uintptr_t) (ptr - stack);
+ if (usage > max_stack_usage) {
+ error_report("thread %d max stack usage increased from %u to %u",
+ qemu_get_thread_id(), max_stack_usage, usage);
+ max_stack_usage = usage;
+ }
+#endif
+
+ munmap(stack, allocsz);
}
--
1.9.1
- [Qemu-devel] [PATCH V8 0/6] coroutine: mmap stack memory and stack size, Peter Lieven, 2016/09/26
- [Qemu-devel] [PATCH V8 2/6] coroutine: add a macro for the coroutine stack size, Peter Lieven, 2016/09/26
- [Qemu-devel] [PATCH V8 6/6] coroutine: reduce stack size to 60kB, Peter Lieven, 2016/09/26
- [Qemu-devel] [PATCH V8 5/6] oslib-posix: add a configure switch to debug stack usage,
Peter Lieven <=
- [Qemu-devel] [PATCH V8 4/6] coroutine-sigaltstack: use helper for allocating stack memory, Peter Lieven, 2016/09/26
- [Qemu-devel] [PATCH V8 3/6] coroutine-ucontext: use helper for allocating stack memory, Peter Lieven, 2016/09/26