cgroups: simplify offline and isolated cpu handling

Don't create separate cpumask arrays for them. Just clear the ones that
are set in the original cpumask array.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index fff80b28db418246fb78ed8a12ae8a37aba32ae3..ff910dedd57e0a52eaa6a2c74f8a0648be48d5c2 100644 (file)
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -262,6 +262,50 @@ static int lxc_cpumask(char *buf, uint32_t **bitarr, size_t *last_set_bit)
        return 0;
 }
 
+static int lxc_cpumask_update(char *buf, uint32_t *bitarr, size_t last_set_bit,
+                             bool clear)
+{
+       bool flipped = false;
+       char *token;
+
+       lxc_iterate_parts(token, buf, ",") {
+               unsigned last_bit, first_bit;
+               char *range;
+
+               errno = 0;
+               first_bit = strtoul(token, NULL, 0);
+               last_bit = first_bit;
+               range = strchr(token, '-');
+               if (range)
+                       last_bit = strtoul(range + 1, NULL, 0);
+
+               if (!(first_bit <= last_bit)) {
+                       WARN("The cup range seems to be inverted: %u-%u", first_bit, last_bit);
+                       continue;
+               }
+
+               if (last_bit > last_set_bit)
+                       continue;
+
+               while (first_bit <= last_bit) {
+                       if (clear && is_set(first_bit, bitarr)) {
+                               flipped = true;
+                               clear_bit(first_bit, bitarr);
+                       } else if (!clear && !is_set(first_bit, bitarr)) {
+                               flipped = true;
+                               set_bit(first_bit, bitarr);
+                       }
+
+                       first_bit++;
+               }
+       }
+
+       if (flipped)
+               return 1;
+
+       return 0;
+}
+
 /* Turn cpumask into simple, comma-separated cpulist. */
 static char *lxc_cpumask_to_cpulist(uint32_t *bitarr, size_t last_set_bit)
 {
@@ -554,12 +598,9 @@ static bool cpuset1_cpus_initialize(int dfd_parent, int dfd_child,
 {
        __do_free char *cpulist = NULL, *fpath = NULL, *isolcpus = NULL,
                       *offlinecpus = NULL, *posscpus = NULL;
-       __do_free uint32_t *isolmask = NULL, *offlinemask = NULL,
-                          *possmask = NULL;
+       __do_free uint32_t *possmask = NULL;
        int ret;
-       size_t isol_last_set_bit = 0, offline_last_set_bit = 0,
-              poss_last_set_bit = 0;
-       bool flipped_bit = false;
+       size_t poss_last_set_bit = 0;
 
        posscpus = read_file_at(dfd_parent, "cpuset.cpus", PROTECT_OPEN, 0);
        if (!posscpus)
@@ -596,33 +637,13 @@ static bool cpuset1_cpus_initialize(int dfd_parent, int dfd_child,
        if (ret)
                return log_error_errno(false, errno, "Failed to create cpumask for possible cpus");
 
-       if (isolcpus) {
-               ret = lxc_cpumask(isolcpus, &isolmask, &isol_last_set_bit);
-               if (ret)
-                       return log_error_errno(false, errno, "Failed to create cpumask for isolated cpus");
-       }
-
-       if (offlinecpus) {
-               ret = lxc_cpumask(offlinecpus, &offlinemask, &offline_last_set_bit);
-               if (ret)
-                       return log_error_errno(false, errno, "Failed to create cpumask for offline cpus");
-       }
+       if (isolcpus)
+               ret = lxc_cpumask_update(isolcpus, possmask, poss_last_set_bit, true);
 
-       for (size_t i = 0; i <= poss_last_set_bit; i++) {
-               if (isolmask && (i <= isol_last_set_bit) &&
-                   is_set(i, isolmask) && is_set(i, possmask)) {
-                       flipped_bit = true;
-                       clear_bit(i, possmask);
-               }
-
-               if (offlinemask && (i <= offline_last_set_bit) &&
-                   is_set(i, offlinemask) && is_set(i, possmask)) {
-                       flipped_bit = true;
-                       clear_bit(i, possmask);
-               }
-       }
+       if (offlinecpus)
+               ret |= lxc_cpumask_update(offlinecpus, possmask, poss_last_set_bit, true);
 
-       if (!flipped_bit) {
+       if (!ret) {
                cpulist = lxc_cpumask_to_cpulist(possmask, poss_last_set_bit);
                TRACE("No isolated or offline cpus present in cpuset");
        } else {