hpdata: count active pages instead of free ones.

This will be more consistent with later naming choices.

src/hpa.c

@@ -125,7 +125,7 @@ hpa_should_hugify(hpa_shard_t *shard, hpdata_t *ps) {
 	 * inactive.  Eventually, this should be a malloc conf option.
 	 */
 	return !hpdata_huge_get(ps)
-	    && hpdata_nfree_get(ps) < (HUGEPAGE / PAGE) * 5 / 100;
+	    && hpdata_nactive_get(ps) >= (HUGEPAGE_PAGES) * 95 / 100;
 }
 
 /* Returns true on error. */

src/hpdata.c

@@ -22,7 +22,7 @@ hpdata_init(hpdata_t *hpdata, void *addr, uint64_t age) {
 	hpdata_addr_set(hpdata, addr);
 	hpdata_age_set(hpdata, age);
 	hpdata_huge_set(hpdata, false);
-	hpdata_nfree_set(hpdata, HUGEPAGE_PAGES);
+	hpdata->h_nactive = 0;
 	hpdata_longest_free_range_set(hpdata, HUGEPAGE_PAGES);
 	fb_init(hpdata->active_pages, HUGEPAGE_PAGES);
 
@@ -72,7 +72,7 @@ hpdata_reserve_alloc(hpdata_t *hpdata, size_t sz) {
 	/* We found a range; remember it. */
 	result = begin;
 	fb_set_range(hpdata->active_pages, HUGEPAGE_PAGES, begin, npages);
-	hpdata_nfree_set(hpdata, hpdata_nfree_get(hpdata) - npages);
+	hpdata->h_nactive += npages;
 
 	/*
 	 * We might have shrunk the longest free range.  We have to keep
@@ -123,7 +123,7 @@ hpdata_unreserve(hpdata_t *hpdata, void *addr, size_t sz) {
 		hpdata_longest_free_range_set(hpdata, new_range_len);
 	}
 
-	hpdata_nfree_set(hpdata, hpdata_nfree_get(hpdata) + npages);
+	hpdata->h_nactive -= npages;
 
 	hpdata_assert_consistent(hpdata);
 }

src/psset.c

@@ -57,8 +57,8 @@ psset_bin_stats_insert_remove(psset_bin_stats_t *binstats, hpdata_t *ps,
 	size_t *ninactive_dst = hpdata_huge_get(ps)
 	    ? &binstats->ninactive_huge : &binstats->ninactive_nonhuge;
 
-	size_t ninactive = hpdata_nfree_get(ps);
-	size_t nactive = HUGEPAGE_PAGES - ninactive;
+	size_t nactive = hpdata_nactive_get(ps);
+	size_t ninactive = HUGEPAGE_PAGES - nactive;
 
 	size_t mul = insert ? (size_t)1 : (size_t)-1;
 	*npageslabs_dst += mul * 1;