# HG changeset patch
# User Andre Przywara <andre.przywara@xxxxxxx>
# Date 1296840759 0
# Node ID 068b3f19ef9a9139f04cd836249fd444dc71dafa
# Parent 4bdb78db22b640794bf9ae14a101303d46849593
xl: fix broken xl vcpu-list output (tool hangs on large machines)
The algorithm for printing the CPU affinity in a condensed way
looks for a set bit in a zero-byte:
for (i = 0; !(pcpumap & 1); ++i, pcpumap >>= 1)
Looking at the code I found that it is entirely broken if more than 8
CPUs are used. Beside that endless loop issue the output is totally
bogus except for the "any CPU" case, which is handled explicitly earlier.
I tried to fix it, but the whole approach does not work if the outer
loops actually iterates (executing more than once).
This fix reimplements the whole algorithm in a clean (though not much
optimized way). It survived some unit-testing.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Committed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
tools/libxl/xl_cmdimpl.c | 96 +++++++++++++++++++++++++----------------------
1 files changed, 52 insertions(+), 44 deletions(-)
diff -r 4bdb78db22b6 -r 068b3f19ef9a tools/libxl/xl_cmdimpl.c
--- a/tools/libxl/xl_cmdimpl.c Wed Feb 02 17:06:36 2011 +0000
+++ b/tools/libxl/xl_cmdimpl.c Fri Feb 04 17:32:39 2011 +0000
@@ -3344,13 +3344,60 @@ int main_button_press(int argc, char **a
return 0;
}
+static void print_bitmap(uint8_t *map, int maplen, FILE *stream)
+{
+ int i;
+ uint8_t pmap, bitmask;
+ int firstset, state = 0;
+
+ for (i = 0; i < maplen; i++) {
+ if (i % 8 == 0) {
+ pmap = *map++;
+ bitmask = 1;
+ } else bitmask <<= 1;
+
+ switch (state) {
+ case 0:
+ case 2:
+ if ((pmap & bitmask) != 0) {
+ firstset = i;
+ state++;
+ }
+ continue;
+ case 1:
+ case 3:
+ if ((pmap & bitmask) == 0) {
+ fprintf(stream, "%s%d", state > 1 ? "," : "", firstset);
+ if (i - 1 > firstset)
+ fprintf(stream, "-%d", i - 1);
+ state = 2;
+ }
+ continue;
+ }
+ }
+ switch (state) {
+ case 0:
+ fprintf(stream, "none");
+ break;
+ case 2:
+ break;
+ case 1:
+ if (firstset == 0) {
+ fprintf(stream, "any cpu");
+ break;
+ }
+ case 3:
+ fprintf(stream, "%s%d", state > 1 ? "," : "", firstset);
+ if (i - 1 > firstset)
+ fprintf(stream, "-%d", i - 1);
+ break;
+ }
+}
+
static void print_vcpuinfo(uint32_t tdomid,
const libxl_vcpuinfo *vcpuinfo,
uint32_t nr_cpus)
{
- int i, l;
- uint8_t *cpumap;
- uint8_t pcpumap;
char *domname;
/* NAME ID VCPU */
@@ -3370,47 +3417,8 @@ static void print_vcpuinfo(uint32_t tdom
/* TIM */
printf("%9.1f ", ((float)vcpuinfo->vcpu_time / 1e9));
/* CPU AFFINITY */
- pcpumap = nr_cpus > 8 ? (uint8_t)-1 : ((1 << nr_cpus) - 1);
- for (cpumap = vcpuinfo->cpumap.map; nr_cpus; ++cpumap) {
- if (*cpumap < pcpumap) {
- break;
- }
- if (nr_cpus > 8) {
- pcpumap = -1;
- nr_cpus -= 8;
- } else {
- pcpumap = ((1 << nr_cpus) - 1);
- nr_cpus = 0;
- }
- }
- if (!nr_cpus) {
- printf("any cpu\n");
- } else {
- for (cpumap = vcpuinfo->cpumap.map; nr_cpus; ++cpumap) {
- pcpumap = *cpumap;
- for (i = 0; !(pcpumap & 1); ++i, pcpumap >>= 1)
- ;
- printf("%u", i);
- for (l = i, pcpumap = (pcpumap >> 1); (pcpumap & 1); ++i, pcpumap
>>= 1)
- ;
- if (l < i) {
- printf("-%u", i);
- }
- for (++i; pcpumap; ++i, pcpumap >>= 1) {
- if (pcpumap & 1) {
- printf(",%u", i);
- for (l = i, pcpumap = (pcpumap >> 1); (pcpumap & 1); ++i,
pcpumap >>= 1)
- ;
- if (l < i) {
- printf("-%u", i);
- }
- ++i;
- }
- }
- printf("\n");
- nr_cpus = nr_cpus > 8 ? nr_cpus - 8 : 0;
- }
- }
+ print_bitmap(vcpuinfo->cpumap.map, nr_cpus, stdout);
+ printf("\n");
}
static void print_domain_vcpuinfo(uint32_t domid, uint32_t nr_cpus)
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