SEC: Expand option configurability.

This change pulls the SEC options into a struct, which simplifies their handling
across various modules (e.g. PA needs to forward on SEC options from the
malloc_conf string, but it doesn't really need to know their names).  While
we're here, make some of the fixed constants configurable, and unify naming from
the configuration options to the internals.

include/jemalloc/internal/jemalloc_internal_externs.h

@@ -3,6 +3,7 @@
 
 #include "jemalloc/internal/atomic.h"
 #include "jemalloc/internal/hpa_opts.h"
+#include "jemalloc/internal/sec_opts.h"
 #include "jemalloc/internal/tsd_types.h"
 #include "jemalloc/internal/nstime.h"
 
@@ -16,9 +17,7 @@ extern bool opt_trust_madvise;
 extern bool opt_confirm_conf;
 extern bool opt_hpa;
 extern hpa_shard_opts_t opt_hpa_opts;
-extern size_t opt_hpa_sec_max_alloc;
-extern size_t opt_hpa_sec_max_bytes;
-extern size_t opt_hpa_sec_nshards;
+extern sec_opts_t opt_hpa_sec_opts;
 
 extern const char *opt_junk;
 extern bool opt_junk_alloc;

include/jemalloc/internal/pa.h

@@ -131,7 +131,7 @@ bool pa_shard_init(tsdn_t *tsdn, pa_shard_t *shard, emap_t *emap, base_t *base,
  * that we can boot without worrying about the HPA, then turn it on in a0.
  */
 bool pa_shard_enable_hpa(pa_shard_t *shard, const hpa_shard_opts_t *hpa_opts,
-    size_t sec_nshards, size_t sec_alloc_max, size_t sec_bytes_max);
+    const sec_opts_t *hpa_sec_opts);
 /*
  * We stop using the HPA when custom extent hooks are installed, but still
  * redirect deallocations to it.

include/jemalloc/internal/sec.h

@@ -103,49 +103,11 @@ struct sec_s {
 	pai_t pai;
 	pai_t *fallback;
 
-	/*
-	 * We'll automatically refuse to cache any objects in this sec if
-	 * they're larger than alloc_max bytes.
-	 */
-	size_t alloc_max;
-	/*
-	 * Exceeding this amount of cached extents in a shard causes *all* of
-	 * the bins in that shard to be flushed.
-	 */
-	size_t bytes_max;
-	/*
-	 * The number of bytes (in all bins) we flush down to when we exceed
-	 * bytes_cur.  We want this to be less than bytes_cur, because
-	 * otherwise we could get into situations where a shard undergoing
-	 * net-deallocation keeps bytes_cur very near to bytes_max, so that
-	 * most deallocations get immediately forwarded to the underlying PAI
-	 * implementation, defeating the point of the SEC.
-	 *
-	 * Currently this is just set to bytes_max / 2, but eventually can be
-	 * configurable.
-	 */
-	size_t bytes_after_flush;
-
-	/*
-	 * When we can't satisfy an allocation out of the SEC because there are
-	 * no available ones cached, we allocate multiple of that size out of
-	 * the fallback allocator.  Eventually we might want to do something
-	 * cleverer, but for now we just grab a fixed number.
-	 *
-	 * For now, just the constant 4.  Eventually, it should be configurable.
-	 */
-	size_t batch_fill_extra;
-
-	/*
-	 * We don't necessarily always use all the shards; requests are
-	 * distributed across shards [0, nshards - 1).
-	 */
-	size_t nshards;
+	sec_opts_t opts;
 	sec_shard_t shards[SEC_NSHARDS_MAX];
 };
 
-bool sec_init(sec_t *sec, pai_t *fallback, size_t nshards, size_t alloc_max,
-    size_t bytes_max);
+bool sec_init(sec_t *sec, pai_t *fallback, const sec_opts_t *opts);
 void sec_flush(tsdn_t *tsdn, sec_t *sec);
 void sec_disable(tsdn_t *tsdn, sec_t *sec);
 

include/jemalloc/internal/sec_opts.h

@@ -0,0 +1,59 @@
+#ifndef JEMALLOC_INTERNAL_SEC_OPTS_H
+#define JEMALLOC_INTERNAL_SEC_OPTS_H
+
+/*
+ * The configuration settings used by an sec_t.  Morally, this is part of the
+ * SEC interface, but we put it here for header-ordering reasons.
+ */
+
+typedef struct sec_opts_s sec_opts_t;
+struct sec_opts_s {
+	/*
+	 * We don't necessarily always use all the shards; requests are
+	 * distributed across shards [0, nshards - 1).
+	 */
+	size_t nshards;
+	/*
+	 * We'll automatically refuse to cache any objects in this sec if
+	 * they're larger than max_alloc bytes, instead forwarding such objects
+	 * directly to the fallback.
+	 */
+	size_t max_alloc;
+	/*
+	 * Exceeding this amount of cached extents in a shard causes us to start
+	 * flushing bins in that shard until we fall below bytes_after_flush.
+	 */
+	size_t max_bytes;
+	/*
+	 * The number of bytes (in all bins) we flush down to when we exceed
+	 * bytes_cur.  We want this to be less than bytes_cur, because
+	 * otherwise we could get into situations where a shard undergoing
+	 * net-deallocation keeps bytes_cur very near to max_bytes, so that
+	 * most deallocations get immediately forwarded to the underlying PAI
+	 * implementation, defeating the point of the SEC.
+	 */
+	size_t bytes_after_flush;
+	/*
+	 * When we can't satisfy an allocation out of the SEC because there are
+	 * no available ones cached, we allocate multiple of that size out of
+	 * the fallback allocator.  Eventually we might want to do something
+	 * cleverer, but for now we just grab a fixed number.
+	 */
+	size_t batch_fill_extra;
+};
+
+#define SEC_OPTS_DEFAULT {						\
+	/* nshards */							\
+	4,								\
+	/* max_alloc */							\
+	32 * 1024,							\
+	/* max_bytes */							\
+	256 * 1024,							\
+	/* bytes_after_flush */						\
+	128 * 1024,							\
+	/* batch_fill_extra */						\
+	0								\
+}
+
+
+#endif /* JEMALLOC_INTERNAL_SEC_OPTS_H */