oomd: refactor pgscan_rate calculation into helper

diff --git a/src/oom/oomd-util.c b/src/oom/oomd-util.c
index 894d23a83a4a19746efec90d6de105fc622ed9bc..5133b1c060c0985812c50e7ed676de18de468b8a 100644 (file)
--- a/src/oom/oomd-util.c
+++ b/src/oom/oomd-util.c
@@ -134,6 +134,23 @@ bool oomd_memory_reclaim(Hashmap *h) {
         return pgscan_of > last_pgscan_of;
 }
 
+uint64_t oomd_pgscan_rate(const OomdCGroupContext *c) {
+        uint64_t last_pgscan;
+
+        assert(c);
+
+        /* If last_pgscan > pgscan, assume the cgroup was recreated and reset last_pgscan to zero.
+         * pgscan is monotonic and in practice should not decrease (except in the recreation case). */
+        last_pgscan = c->last_pgscan;
+        if (c->last_pgscan > c->pgscan) {
+                log_debug("Last pgscan %"PRIu64" greater than current pgscan %"PRIu64" for %s. Using last pgscan of zero.",
+                                c->last_pgscan, c->pgscan, c->path);
+                last_pgscan = 0;
+        }
+
+        return c->pgscan - last_pgscan;
+}
+
 bool oomd_swap_free_below(const OomdSystemContext *ctx, int threshold_permyriad) {
         uint64_t swap_threshold;
 

diff --git a/src/oom/oomd-util.h b/src/oom/oomd-util.h
index 51423130d1b8c8c964d3b608f04fa0841e02148c..af08504c5bb9a9e0036ffa2dfcf75cb275821866 100644 (file)
--- a/src/oom/oomd-util.h
+++ b/src/oom/oomd-util.h
@@ -64,10 +64,13 @@ bool oomd_memory_reclaim(Hashmap *h);
 /* Returns true if the amount of swap free is below the permyriad of swap specified by `threshold_permyriad`. */
 bool oomd_swap_free_below(const OomdSystemContext *ctx, int threshold_permyriad);
 
+/* Returns pgscan - last_pgscan, accounting for corner cases. */
+uint64_t oomd_pgscan_rate(const OomdCGroupContext *c);
+
 /* The compare functions will sort from largest to smallest, putting all the contexts with "avoid" at the end
  * (after the smallest values). */
 static inline int compare_pgscan_rate_and_memory_usage(OomdCGroupContext * const *c1, OomdCGroupContext * const *c2) {
-        uint64_t last1, last2;
+        uint64_t diff1, diff2;
         int r;
 
         assert(c1);
@@ -77,22 +80,9 @@ static inline int compare_pgscan_rate_and_memory_usage(OomdCGroupContext * const
         if (r != 0)
                 return r;
 
-        /* If last_pgscan > pgscan, assume the cgroup was recreated and reset last_pgscan to zero. */
-        last2 = (*c2)->last_pgscan;
-        if ((*c2)->last_pgscan > (*c2)->pgscan) {
-                log_info("Last pgscan %" PRIu64 "greater than current pgscan %" PRIu64 "for %s. Using last pgscan of zero.",
-                                (*c2)->last_pgscan, (*c2)->pgscan, (*c2)->path);
-                last2 = 0;
-        }
-
-        last1 = (*c1)->last_pgscan;
-        if ((*c1)->last_pgscan > (*c1)->pgscan) {
-                log_info("Last pgscan %" PRIu64 "greater than current pgscan %" PRIu64 "for %s. Using last pgscan of zero.",
-                                (*c1)->last_pgscan, (*c1)->pgscan, (*c1)->path);
-                last1 = 0;
-        }
-
-        r = CMP((*c2)->pgscan - last2, (*c1)->pgscan - last1);
+        diff1 = oomd_pgscan_rate(*c1);
+        diff2 = oomd_pgscan_rate(*c2);
+        r = CMP(diff2, diff1);
         if (r != 0)
                 return r;