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trace: add trace_event_get_state_backends()

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Code that checks dstate is unaware of SystemTap and LTTng UST dstate, so
the following trace event will not fire when solely enabled by SystemTap
or LTTng UST:

  if (trace_event_get_state(TRACE_MY_EVENT)) {
      str = g_strdup_printf("Expensive string to generate ...",
                            ...);
      trace_my_event(str);
      g_free(str);
  }

Add trace_event_get_state_backends() to fetch backend dstate.  Those
backends that use QEMU dstate fetch it as part of
generate_h_backend_dstate().

Update existing trace_event_get_state() callers to use
trace_event_get_state_backends() instead.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170731140718.22010-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2017-07-31 15:07:18 +01:00
parent 3932ef3ffb
commit d87aa13803
5 changed files with 31 additions and 17 deletions
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2
docs/devel/tracing.txt
View File

@ -353,7 +353,7 @@ guard such computations and avoid its compilation when the event is disabled:
}
You can check both if the event has been disabled and is dynamically enabled at
the same time using the 'trace_event_get_state' routine (see header
the same time using the 'trace_event_get_state_backends' routine (see header
"trace/control.h" for more information).
=== "tcg" ===

13
hw/usb/hcd-ohci.c
View File

@ -936,16 +936,18 @@ static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed,
return 1;
}
#ifdef trace_event_get_state
static void ohci_td_pkt(const char *msg, const uint8_t *buf, size_t len)
{
bool print16 = !!trace_event_get_state(TRACE_USB_OHCI_TD_PKT_SHORT);
bool printall = !!trace_event_get_state(TRACE_USB_OHCI_TD_PKT_FULL);
bool print16;
bool printall;
const int width = 16;
int i;
char tmp[3 * width + 1];
char *p = tmp;
print16 = !!trace_event_get_state_backends(TRACE_USB_OHCI_TD_PKT_SHORT);
printall = !!trace_event_get_state_backends(TRACE_USB_OHCI_TD_PKT_FULL);
if (!printall && !print16) {
return;
}
@ -967,11 +969,6 @@ static void ohci_td_pkt(const char *msg, const uint8_t *buf, size_t len)
p += sprintf(p, " %.2x", buf[i]);
}
}
#else
static void ohci_td_pkt(const char *msg, const uint8_t *buf, size_t len)
{
}
#endif
/* Service a transport descriptor.
Returns nonzero to terminate processing of this endpoint. */

11
net/colo-compare.c
View File

@ -188,7 +188,7 @@ static int packet_enqueue(CompareState *s, int mode)
*/
static int colo_packet_compare_common(Packet *ppkt, Packet *spkt, int offset)
{
if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
@ -274,7 +274,8 @@ static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt)
res = -1;
}
if (res != 0 && trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
if (res != 0 &&
trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
@ -334,7 +335,7 @@ static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
if (ret) {
trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size);
trace_colo_compare_udp_miscompare("Secondary pkt size", spkt->size);
if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
ppkt->size);
qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
@ -371,7 +372,7 @@ static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
ppkt->size);
trace_colo_compare_icmp_miscompare("Secondary pkt size",
spkt->size);
if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
ppkt->size);
qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
@ -390,7 +391,7 @@ static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
{
trace_colo_compare_main("compare other");
if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));

4
net/filter-rewriter.c
View File

@ -69,7 +69,7 @@ static int handle_primary_tcp_pkt(NetFilterState *nf,
struct tcphdr *tcp_pkt;
tcp_pkt = (struct tcphdr *)pkt->transport_header;
if (trace_event_get_state(TRACE_COLO_FILTER_REWRITER_DEBUG)) {
if (trace_event_get_state_backends(TRACE_COLO_FILTER_REWRITER_DEBUG)) {
trace_colo_filter_rewriter_pkt_info(__func__,
inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst),
ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),
@ -115,7 +115,7 @@ static int handle_secondary_tcp_pkt(NetFilterState *nf,
tcp_pkt = (struct tcphdr *)pkt->transport_header;
if (trace_event_get_state(TRACE_COLO_FILTER_REWRITER_DEBUG)) {
if (trace_event_get_state_backends(TRACE_COLO_FILTER_REWRITER_DEBUG)) {
trace_colo_filter_rewriter_pkt_info(__func__,
inet_ntoa(pkt->ip->ip_src), inet_ntoa(pkt->ip->ip_dst),
ntohl(tcp_pkt->th_seq), ntohl(tcp_pkt->th_ack),

18
trace/control.h
View File

@ -96,7 +96,7 @@ static const char * trace_event_get_name(TraceEvent *ev);
* trace_event_get_state:
* @id: Event identifier name.
*
* Get the tracing state of an event (both static and dynamic).
* Get the tracing state of an event, both static and the QEMU dynamic state.
*
* If the event has the disabled property, the check will have no performance
* impact.
@ -104,6 +104,22 @@ static const char * trace_event_get_name(TraceEvent *ev);
#define trace_event_get_state(id) \
((id ##_ENABLED) && trace_event_get_state_dynamic_by_id(id))
/**
* trace_event_get_state_backends:
* @id: Event identifier name.
*
* Get the tracing state of an event, both static and dynamic state from all
* compiled-in backends.
*
* If the event has the disabled property, the check will have no performance
* impact.
*
* Returns: true if at least one backend has the event enabled and the event
* does not have the disabled property.
*/
#define trace_event_get_state_backends(id) \
((id ##_ENABLED) && id ##_BACKEND_DSTATE())
/**
* trace_event_get_vcpu_state:
* @vcpu: Target vCPU.