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Date:      Fri, 2 May 2014 07:57:40 +0000 (UTC)
From:      Robert Watson <rwatson@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r265216 - in head/sys: kern sys
Message-ID:  <201405020757.s427veV4015749@svn.freebsd.org>
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Author: rwatson
Date: Fri May  2 07:57:40 2014
New Revision: 265216
URL: http://svnweb.freebsd.org/changeset/base/265216

Log:
  Garbage collect mtxpool_lockbuilder, the mutex pool historically used
  for lockmgr and sx interlocks, but unused since optimised versions of
  those sleep locks were introduced.  This will save a (quite) small
  amount of memory in all kernel configurations.  The sleep mutex pool is
  retained as it is used for 'struct bio' and several other consumers.
  
  Discussed with:	jhb
  MFC after:	3 days

Modified:
  head/sys/kern/kern_mtxpool.c
  head/sys/sys/kernel.h
  head/sys/sys/mutex.h

Modified: head/sys/kern/kern_mtxpool.c
==============================================================================
--- head/sys/kern/kern_mtxpool.c	Fri May  2 07:14:22 2014	(r265215)
+++ head/sys/kern/kern_mtxpool.c	Fri May  2 07:57:40 2014	(r265216)
@@ -59,9 +59,6 @@ __FBSDID("$FreeBSD$");
 static MALLOC_DEFINE(M_MTXPOOL, "mtx_pool", "mutex pool");
 
 /* Pool sizes must be a power of two */
-#ifndef MTX_POOL_LOCKBUILDER_SIZE
-#define MTX_POOL_LOCKBUILDER_SIZE	128
-#endif
 #ifndef MTX_POOL_SLEEP_SIZE
 #define MTX_POOL_SLEEP_SIZE		128
 #endif
@@ -78,18 +75,12 @@ struct mtx_pool {
 	struct mtx	mtx_pool_ary[1];
 };
 
-static struct mtx_pool_lockbuilder {
-	struct mtxpool_header mtx_pool_header;
-	struct mtx	mtx_pool_ary[MTX_POOL_LOCKBUILDER_SIZE];
-} lockbuilder_pool;
-
 #define mtx_pool_size	mtx_pool_header.mtxpool_size
 #define mtx_pool_mask	mtx_pool_header.mtxpool_mask
 #define mtx_pool_shift	mtx_pool_header.mtxpool_shift
 #define mtx_pool_next	mtx_pool_header.mtxpool_next
 
 struct mtx_pool *mtxpool_sleep;
-struct mtx_pool *mtxpool_lockbuilder;
 
 #if UINTPTR_MAX == UINT64_MAX	/* 64 bits */
 # define POINTER_BITS		64
@@ -166,15 +157,6 @@ mtx_pool_destroy(struct mtx_pool **poolp
 }
 
 static void
-mtx_pool_setup_static(void *dummy __unused)
-{
-	mtx_pool_initialize((struct mtx_pool *)&lockbuilder_pool,
-	    "lockbuilder mtxpool", MTX_POOL_LOCKBUILDER_SIZE,
-	    MTX_DEF | MTX_NOWITNESS | MTX_QUIET);
-	mtxpool_lockbuilder = (struct mtx_pool *)&lockbuilder_pool;
-}
-
-static void
 mtx_pool_setup_dynamic(void *dummy __unused)
 {
 	mtxpool_sleep = mtx_pool_create("sleep mtxpool",
@@ -202,17 +184,5 @@ mtx_pool_alloc(struct mtx_pool *pool)
 	return (&pool->mtx_pool_ary[i]);
 }
 
-/*
- * The lockbuilder pool must be initialized early because the lockmgr
- * and sx locks depend on it.  The sx locks are used in the kernel
- * memory allocator.  The lockmgr subsystem is initialized by
- * SYSINIT(..., SI_SUB_LOCKMGR, ...).
- *
- * We can't call malloc() to dynamically allocate the sleep pool
- * until after kmeminit() has been called, which is done by
- * SYSINIT(..., SI_SUB_KMEM, ...).
- */
-SYSINIT(mtxpooli1, SI_SUB_MTX_POOL_STATIC, SI_ORDER_FIRST,
-    mtx_pool_setup_static, NULL);
 SYSINIT(mtxpooli2, SI_SUB_MTX_POOL_DYNAMIC, SI_ORDER_FIRST,
     mtx_pool_setup_dynamic, NULL);

Modified: head/sys/sys/kernel.h
==============================================================================
--- head/sys/sys/kernel.h	Fri May  2 07:14:22 2014	(r265215)
+++ head/sys/sys/kernel.h	Fri May  2 07:57:40 2014	(r265216)
@@ -92,7 +92,6 @@ enum sysinit_sub_id {
 	SI_SUB_COPYRIGHT	= 0x0800001,	/* first use of console*/
 	SI_SUB_SETTINGS		= 0x0880000,	/* check and recheck settings */
 	SI_SUB_MTX_POOL_STATIC	= 0x0900000,	/* static mutex pool */
-	SI_SUB_LOCKMGR		= 0x0980000,	/* lockmgr locks */
 	SI_SUB_VM		= 0x1000000,	/* virtual memory system init*/
 	SI_SUB_KMEM		= 0x1800000,	/* kernel memory*/
 	SI_SUB_KVM_RSRC		= 0x1A00000,	/* kvm operational limits*/

Modified: head/sys/sys/mutex.h
==============================================================================
--- head/sys/sys/mutex.h	Fri May  2 07:14:22 2014	(r265215)
+++ head/sys/sys/mutex.h	Fri May  2 07:57:40 2014	(r265216)
@@ -323,12 +323,8 @@ struct mtx *mtx_pool_alloc(struct mtx_po
 	mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
 
 /*
- * mtxpool_lockbuilder is a pool of sleep locks that is not witness
- * checked and should only be used for building higher level locks.
- *
  * mtxpool_sleep is a general purpose pool of sleep mutexes.
  */
-extern struct mtx_pool *mtxpool_lockbuilder;
 extern struct mtx_pool *mtxpool_sleep;
 
 #ifndef LOCK_DEBUG

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