-/* A fast RSS sampling function.
- *
- * The function is reasonably accurate while fast, since it uses the trick of
- * using the server.fragmentation ratio that is computed every second and
- * is the ratio between the RSS and our zmalloc() count of allocated bytes.
- *
- * So in order to compute the current RSS used we just need to multiply
- * the zmalloc() memory reporting, that is as fast as reading a counter,
- * for the latest estimation of fragmentation.
- *
- * The behavior of this function is also very desirable because it is
- * very responsive to memory changes: while the real RSS is actually measured
- * in pages, the RSS estimation will actually change even if just a few bytes
- * are freed, and this is a good property when the function is used in order
- * to evict keys for Virtual Memory of for 'maxmemory' directive.
- *
- * Note that when the memory reported by zmalloc is smaller than the RSS
- * (that is, fragmentation < 1) this means that something is odd (many pages
- * swapped since the Redis instance is idle) and we consider the fragmentation
- * ratio 1. */
-size_t redisEstimateRSS(void) {
- size_t used = zmalloc_used_memory();
- float maxfrag;
-
- if (server.fragmentation < 1) return used;
- maxfrag = (float)SIZE_MAX / used;
-
- /* If multiplying memory usage reported by zmalloc per fragmentation
- * ratio will lead to an overflow we just return SIZE_MAX. */
- if (maxfrag < server.fragmentation) return SIZE_MAX;
-
- return (size_t)((used * server.fragmentation));
-}
-