code cleanup and commenting
Costa Tsaousis (ktsaou) committed
Jan 29, 2017 at 09:10 UTC
19c7ffc053db632f4e0fd62e44d323f018895921
1 file changed
+42
-15
src/plugin_tc.c
+42
-15
@@ -230,17 +230,20 @@ static inline void tc_device_commit(struct tc_device *d) {
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int active_nodes = 0, updated_classes = 0, updated_qdiscs = 0;
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// prepare all classes
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+ // we set reasonable defaults for the rest of the code below
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+
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for(c = d->classes ; c ; c = c->next) {
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- c->render = 0;
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+ c->render = 0; // do not render this class
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- c->isleaf = 1;
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- c->hasparent = 0;
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+ c->isleaf = 1; // this is a leaf class
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+ c->hasparent = 0; // without a parent
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if(unlikely(!c->updated))
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- c->unupdated++;
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+ c->unupdated++; // increase its unupdated counter
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else {
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- c->unupdated = 0;
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+ c->unupdated = 0; // reset its unupdated counter
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+ // count how many of each kind
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if(c->isqdisc)
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updated_qdiscs++;
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else
@@ -256,6 +259,8 @@ static inline void tc_device_commit(struct tc_device *d) {
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if(unlikely(updated_classes && updated_qdiscs)) {
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error("TC: device '%s' has active both classes (%d) and qdiscs (%d). Will render only qdiscs.", d->id, updated_classes, updated_qdiscs);
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+
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+ // set all classes to !updated
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for(c = d->classes ; c ; c = c->next)
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if(unlikely(!c->isqdisc && c->updated))
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c->updated = 0;
@@ -264,6 +269,20 @@ static inline void tc_device_commit(struct tc_device *d) {
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}
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// mark the classes as leafs and parents
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+ //
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+ // TC is hierarchical:
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+ // - classes can have other classes in them
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+ // - the same is true for qdiscs (i.e. qdiscs have classes, that have other qdiscs)
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+ //
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+ // we need to present a chart with leaf nodes only, so that the sum
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+ // of all dimensions of the chart, will be the total utilization
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+ // of the interface.
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+ //
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+ // here we try to find the ones we need to report
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+ // by default all nodes are marked with: isleaf = 1 (see above)
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+ //
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+ // so, here we remove the isleaf flag from nodes in the middle
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+ // and we add the hasparent flag to leaf nodes we found their parent
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for(c = d->classes; c; c = c->next) {
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if(unlikely(!c->updated)) continue;
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@@ -278,6 +297,10 @@ static inline void tc_device_commit(struct tc_device *d) {
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for(x = d->classes; x; x = x->next) {
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if(unlikely(!x->updated || c == x || !x->parentid)) continue;
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+ // classes have both parentid and leafid
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+ // qdiscs have only parentid
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+ // the following works for both (it is an OR)
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+
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if( (c->hash == x->parent_hash && strcmp(c->id, x->parentid) == 0) ||
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(c->leafid && c->leaf_hash == x->parent_hash && strcmp(c->leafid, x->parentid) == 0)) {
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// debug(D_TC_LOOP, "TC: In device '%s', %s '%s' (leafid: '%s') has as leaf %s '%s' (parentid: '%s').", d->name?d->name:d->id, c->isqdisc?"qdisc":"class", c->name?c->name:c->id, c->leafid?c->leafid:c->id, x->isqdisc?"qdisc":"class", x->name?x->name:x->id, x->parentid?x->parentid:x->id);
@@ -287,16 +310,6 @@ static inline void tc_device_commit(struct tc_device *d) {
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}
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}
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- // debugging only
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- /*
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- if(unlikely(debug_flags & D_TC_LOOP)) {
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- for(c = d->classes ; c ; c = c->next) {
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- if((c->isleaf && c->hasparent) || d->enabled_all_classes_qdiscs) debug(D_TC_LOOP, "TC: final nodes dump for '%s': class %s, OK", d->name, c->id);
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- else debug(D_TC_LOOP, "TC: final nodes dump for '%s': class %s, IGNORE (isleaf: %d, hasparent: %d, parent: %s)", d->name?d->name:d->id, c->id, c->isleaf, c->hasparent, c->parentid?c->parentid:"(unset)");
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- }
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- }
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- */
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-
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for(c = d->classes ; c ; c = c->next) {
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if(unlikely(!c->updated)) continue;
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@@ -319,6 +332,17 @@ static inline void tc_device_commit(struct tc_device *d) {
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//}
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}
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+#ifdef NETDATA_INTERNAL_CHECKS
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+ // dump all the list to see what we know
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+
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+ if(unlikely(debug_flags & D_TC_LOOP)) {
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+ for(c = d->classes ; c ; c = c->next) {
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+ if(c->render) debug(D_TC_LOOP, "TC: final nodes dump for '%s': class %s, OK", d->name, c->id);
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+ else debug(D_TC_LOOP, "TC: final nodes dump for '%s': class %s, IGNORE (updated: %d, isleaf: %d, hasparent: %d, parent: %s)", d->name?d->name:d->id, c->id, c->updated, c->isleaf, c->hasparent, c->parentid?c->parentid:"(unset)");
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+ }
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+ }
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+#endif
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+
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if(unlikely(!active_nodes)) {
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debug(D_TC_LOOP, "TC: Ignoring TC device '%s'. No useful classes/qdiscs.", d->name?d->name:d->id);
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tc_device_classes_cleanup(d);
@@ -826,6 +850,9 @@ void *tc_main(void *ptr) {
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if(parent_is_parent && parentid) {
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// eliminate the minor number from parentid
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+ // why: parentid is the id of the parent class
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+ // but major: is also the id of the parent qdisc
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+
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char *s = parentid;
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while(*s && *s != ':') s++;
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if(*s == ':') s[1] = '\0';