Move hpdata bitmap logic out of the psset.

src/hpdata.c

@@ -16,3 +16,99 @@ hpdata_age_comp(const hpdata_t *a, const hpdata_t *b) {
 }
 
 ph_gen(, hpdata_age_heap_, hpdata_age_heap_t, hpdata_t, ph_link, hpdata_age_comp)
+
+
+void
+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_longest_free_range_set(hpdata, HUGEPAGE_PAGES);
+	fb_init(hpdata->active_pages, HUGEPAGE_PAGES);
+}
+
+size_t
+hpdata_reserve_alloc(hpdata_t *hpdata, size_t npages) {
+	assert(npages <= hpdata_longest_free_range_get(hpdata));
+
+	size_t result;
+
+	size_t start = 0;
+	/*
+	 * These are dead stores, but the compiler will issue warnings on them
+	 * since it can't tell statically that found is always true below.
+	 */
+	size_t begin = 0;
+	size_t len = 0;
+
+	size_t largest_unchosen_range = 0;
+	while (true) {
+		bool found = fb_urange_iter(hpdata->active_pages,
+		    HUGEPAGE_PAGES, start, &begin, &len);
+		/*
+		 * A precondition to this function is that hpdata must be able
+		 * to serve the allocation.
+		 */
+		assert(found);
+		if (len >= npages) {
+			/*
+			 * We use first-fit within the page slabs; this gives
+			 * bounded worst-case fragmentation within a slab.  It's
+			 * not necessarily right; we could experiment with
+			 * various other options.
+			 */
+			break;
+		}
+		if (len > largest_unchosen_range) {
+			largest_unchosen_range = len;
+		}
+		start = begin + len;
+	}
+	/* 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);
+
+	/*
+	 * We might have shrunk the longest free range.  We have to keep
+	 * scanning until the end of the hpdata to be sure.
+	 *
+	 * TODO: As an optimization, we should only do this when the range we
+	 * just allocated from was equal to the longest free range size.
+	 */
+	start = begin + npages;
+	while (start < HUGEPAGE_PAGES) {
+		bool found = fb_urange_iter(hpdata->active_pages,
+		    HUGEPAGE_PAGES, start, &begin, &len);
+		if (!found) {
+			break;
+		}
+		if (len > largest_unchosen_range) {
+			largest_unchosen_range = len;
+		}
+		start = begin + len;
+	}
+	hpdata_longest_free_range_set(hpdata, largest_unchosen_range);
+
+	return result;
+}
+
+void
+hpdata_unreserve(hpdata_t *hpdata, size_t begin, size_t npages) {
+	size_t old_longest_range = hpdata_longest_free_range_get(hpdata);
+
+	fb_unset_range(hpdata->active_pages, HUGEPAGE_PAGES, begin, npages);
+	/* We might have just created a new, larger range. */
+	size_t new_begin = (fb_fls(hpdata->active_pages, HUGEPAGE_PAGES,
+	    begin) + 1);
+	size_t new_end = fb_ffs(hpdata->active_pages, HUGEPAGE_PAGES,
+	    begin + npages - 1);
+	size_t new_range_len = new_end - new_begin;
+
+	if (new_range_len > old_longest_range) {
+		hpdata_longest_free_range_set(hpdata, new_range_len);
+	}
+
+	hpdata_nfree_set(hpdata, hpdata_nfree_get(hpdata) + npages);
+}