Generalize chunk management hooks.

Add the "arena.<i>.chunk_hooks" mallctl, which replaces and expands on
the "arena.<i>.chunk.{alloc,dalloc,purge}" mallctls.  The chunk hooks
allow control over chunk allocation/deallocation, decommit/commit,
purging, and splitting/merging, such that the application can rely on
jemalloc's internal chunk caching and retaining functionality, yet
implement a variety of chunk management mechanisms and policies.

Merge the chunks_[sz]ad_{mmap,dss} red-black trees into
chunks_[sz]ad_retained.  This slightly reduces how hard jemalloc tries
to honor the dss precedence setting; prior to this change the precedence
setting was also consulted when recycling chunks.

Fix chunk purging.  Don't purge chunks in arena_purge_stashed(); instead
deallocate them in arena_unstash_purged(), so that the dirty memory
linkage remains valid until after the last time it is used.

This resolves #176 and #201.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/base.c b/src/base.c
index df3ddb63..5493d0f9 100644
--- a/src/base.c
+++ b/src/base.c
@@ -66,7 +66,7 @@ base_chunk_alloc(size_t minsize)
 			base_resident += PAGE_CEILING(nsize);
 		}
 	}
-	extent_node_init(node, NULL, addr, csize, true);
+	extent_node_init(node, NULL, addr, csize, true, true);
 	return (node);
 }
 
@@ -90,7 +90,7 @@ base_alloc(size_t size)
 	csize = CACHELINE_CEILING(size);
 
 	usize = s2u(csize);
-	extent_node_init(&key, NULL, NULL, usize, false);
+	extent_node_init(&key, NULL, NULL, usize, true, false);
 	malloc_mutex_lock(&base_mtx);
 	node = extent_tree_szad_nsearch(&base_avail_szad, &key);
 	if (node != NULL) {