add defrag hint support into jemalloc 5

valkey-io · Oct 10, 2021 · 29d7f97 · 29d7f97
1 parent 9e5cd2c
commit 29d7f97
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diff --git a/deps/jemalloc/include/jemalloc/internal/jemalloc_internal_inlines_c.h b/deps/jemalloc/include/jemalloc/internal/jemalloc_internal_inlines_c.h
@@ -219,4 +219,32 @@ ixalloc(tsdn_t *tsdn, void *ptr, size_t oldsize, size_t size, size_t extra,
 	    newsize);
 }
 
+JEMALLOC_ALWAYS_INLINE int
+iget_defrag_hint(tsdn_t *tsdn, void* ptr, int *bin_util, int *run_util) {
+	int defrag = 0;
+	rtree_ctx_t rtree_ctx_fallback;
+	rtree_ctx_t *rtree_ctx = tsdn_rtree_ctx(tsdn, &rtree_ctx_fallback);
+	szind_t szind;
+	bool is_slab;
+	rtree_szind_slab_read(tsdn, &extents_rtree, rtree_ctx, (uintptr_t)ptr, true, &szind, &is_slab);
+	if (likely(is_slab)) {
+		/* Small allocation. */
+		extent_t *slab = iealloc(tsdn, ptr);
+		arena_t *arena = extent_arena_get(slab);
+		szind_t binind = extent_szind_get(slab);
+		bin_t *bin = &arena->bins[binind];
+		malloc_mutex_lock(tsdn, &bin->lock);
+		/* don't bother moving allocations from the slab currently used for new allocations */
+		if (slab != bin->slabcur) {
+			const bin_info_t *bin_info = &bin_infos[binind];
+			size_t availregs = bin_info->nregs * bin->stats.curslabs;
+			*bin_util = (bin->stats.curregs<<16) / availregs;
+			*run_util = ((bin_info->nregs - extent_nfree_get(slab))<<16) / bin_info->nregs;
+			defrag = 1;
+		}
+		malloc_mutex_unlock(tsdn, &bin->lock);
+	}
+	return defrag;
+}
+
 #endif /* JEMALLOC_INTERNAL_INLINES_C_H */
diff --git a/deps/jemalloc/include/jemalloc/jemalloc_macros.h.in b/deps/jemalloc/include/jemalloc/jemalloc_macros.h.in
@@ -127,3 +127,7 @@
 #  define JEMALLOC_RESTRICT_RETURN
 #  define JEMALLOC_ALLOCATOR
 #endif
+
+/* This version of Jemalloc, modified for Redis, has the je_get_defrag_hint()
+ * function. */
+#define JEMALLOC_FRAG_HINT
diff --git a/deps/jemalloc/src/jemalloc.c b/deps/jemalloc/src/jemalloc.c
@@ -3920,3 +3920,14 @@ jemalloc_postfork_child(void) {
 }
 
 /******************************************************************************/
+
+/* Helps the application decide if a pointer is worth re-allocating in order to reduce fragmentation.
+ * returns 0 if the allocation is in the currently active run,
+ * or when it is not causing any frag issue (large or huge bin)
+ * returns the bin utilization and run utilization both in fixed point 16:16.
+ * If the application decides to re-allocate it should use MALLOCX_TCACHE_NONE when doing so. */
+JEMALLOC_EXPORT int JEMALLOC_NOTHROW
+get_defrag_hint(void* ptr, int *bin_util, int *run_util) {
+	assert(ptr != NULL);
+	return iget_defrag_hint(TSDN_NULL, ptr, bin_util, run_util);
+}