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Date:      Wed, 14 Apr 2010 06:46:43 +0000 (UTC)
From:      Juli Mallett <jmallett@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-user@freebsd.org
Subject:   svn commit: r206592 - in user/jmallett/octeon/sys/mips: include mips
Message-ID:  <201004140646.o3E6khBa094196@svn.freebsd.org>
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Author: jmallett
Date: Wed Apr 14 06:46:43 2010
New Revision: 206592
URL: http://svn.freebsd.org/changeset/base/206592

Log:
  Switch to using the sfbuf scheme from sparc64, which doesn't allow sharing of
  sf bufs, which complicated the code here and made it hard to use pmap_qremove
  in sf_buf_free (so we didn't use it) because we could free and then reallocate
  an sfbuf and reenter its KVA.  These mappings were guaranteed to be identical,
  but this seems cleaner.

Modified:
  user/jmallett/octeon/sys/mips/include/sf_buf.h
  user/jmallett/octeon/sys/mips/mips/vm_machdep.c

Modified: user/jmallett/octeon/sys/mips/include/sf_buf.h
==============================================================================
--- user/jmallett/octeon/sys/mips/include/sf_buf.h	Wed Apr 14 06:32:19 2010	(r206591)
+++ user/jmallett/octeon/sys/mips/include/sf_buf.h	Wed Apr 14 06:46:43 2010	(r206592)
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2003, 2005 Alan L. Cox <alc@cs.rice.edu>
+ * Copyright (c) 2003 Alan L. Cox <alc@cs.rice.edu>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -23,29 +23,20 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	from: src/sys/i386/include/sf_buf.h,v 1.4 2005/02/13 06:23:13 alc
  * $FreeBSD$
  */
 
 #ifndef _MACHINE_SF_BUF_H_
-#define	_MACHINE_SF_BUF_H_
+#define _MACHINE_SF_BUF_H_
 
 #include <sys/queue.h>
-#include <vm/vm.h>
-#include <vm/vm_param.h>
-#include <vm/vm_page.h>
 
 struct vm_page;
 
 struct sf_buf {
-	LIST_ENTRY(sf_buf) list_entry;	/* list of buffers */
-	TAILQ_ENTRY(sf_buf) free_entry; /* list of buffers */
+	SLIST_ENTRY(sf_buf) free_list;	/* list of free buffer slots */
 	struct		vm_page *m;	/* currently mapped page */
 	vm_offset_t	kva;		/* va of mapping */
-	int		ref_count;	/* usage of this mapping */
-#ifdef SMP
-	cpumask_t	cpumask;	/* cpus on which mapping is valid */
-#endif
 };
 
 static __inline vm_offset_t

Modified: user/jmallett/octeon/sys/mips/mips/vm_machdep.c
==============================================================================
--- user/jmallett/octeon/sys/mips/mips/vm_machdep.c	Wed Apr 14 06:32:19 2010	(r206591)
+++ user/jmallett/octeon/sys/mips/mips/vm_machdep.c	Wed Apr 14 06:46:43 2010	(r206592)
@@ -85,26 +85,18 @@ __FBSDID("$FreeBSD$");
 static void	sf_buf_init(void *arg);
 SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL);
 
-LIST_HEAD(sf_head, sf_buf);
-
-
 /*
- * A hash table of active sendfile(2) buffers
+ * Expanded sf_freelist head.  Really an SLIST_HEAD() in disguise, with the
+ * sf_freelist head with the sf_lock mutex.
  */
-static struct sf_head *sf_buf_active;
-static u_long sf_buf_hashmask;
-
-#define	SF_BUF_HASH(m)	(((m) - vm_page_array) & sf_buf_hashmask)
+static struct {
+	SLIST_HEAD(, sf_buf) sf_head;
+	struct mtx sf_lock;
+} sf_freelist;
 
-static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
 static u_int	sf_buf_alloc_want;
 
 /*
- * A lock used to synchronize access to the hash table and free list
- */
-static struct mtx sf_buf_lock;
-
-/*
  * Finish a fork operation, with process p2 nearly set up.
  * Copy and update the pcb, set up the stack so that the child
  * ready to run and return to user mode.
@@ -479,56 +471,34 @@ sf_buf_init(void *arg)
 	nsfbufs = NSFBUFS;
 	TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs);
 
-	sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
-	TAILQ_INIT(&sf_buf_freelist);
+	mtx_init(&sf_freelist.sf_lock, "sf_bufs list lock", NULL, MTX_DEF);
+	SLIST_INIT(&sf_freelist.sf_head);
 	sf_base = kmem_alloc_nofault(kernel_map, nsfbufs * PAGE_SIZE);
 	sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
 	    M_NOWAIT | M_ZERO);
 	for (i = 0; i < nsfbufs; i++) {
 		sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
-		TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
+		SLIST_INSERT_HEAD(&sf_freelist.sf_head, &sf_bufs[i], free_list);
 	}
 	sf_buf_alloc_want = 0;
-	mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF);
 }
 
 /*
- * Allocate an sf_buf for the given vm_page.  On this machine, however, there
- * is no sf_buf object.	 Instead, an opaque pointer to the given vm_page is
- * returned.
+ * Get an sf_buf from the freelist.  Will block if none are available.
  */
 struct sf_buf *
 sf_buf_alloc(struct vm_page *m, int flags)
 {
-	struct sf_head *hash_list;
 	struct sf_buf *sf;
 	int error;
 
-	hash_list = &sf_buf_active[SF_BUF_HASH(m)];
-	mtx_lock(&sf_buf_lock);
-	LIST_FOREACH(sf, hash_list, list_entry) {
-		if (sf->m == m) {
-			sf->ref_count++;
-			if (sf->ref_count == 1) {
-				TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
-				nsfbufsused++;
-				nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
-			}
-			/*
-			 * Flush all mappings in order to have up to date 
-			 * physycal memory
-			 */
-			pmap_flush_pvcache(sf->m);
-			mips_dcache_inv_range(sf->kva, PAGE_SIZE);
-			goto done;
-		}
-	}
-	while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
+	mtx_lock(&sf_freelist.sf_lock);
+	while ((sf = SLIST_FIRST(&sf_freelist.sf_head)) == NULL) {
 		if (flags & SFB_NOWAIT)
-			goto done;
+			break;
 		sf_buf_alloc_want++;
 		mbstat.sf_allocwait++;
-		error = msleep(&sf_buf_freelist, &sf_buf_lock,
+		error = msleep(&sf_freelist, &sf_freelist.sf_lock,
 		    (flags & SFB_CATCH) ? PCATCH | PVM : PVM, "sfbufa", 0);
 		sf_buf_alloc_want--;
 
@@ -536,42 +506,33 @@ sf_buf_alloc(struct vm_page *m, int flag
 		 * If we got a signal, don't risk going back to sleep.
 		 */
 		if (error)
-			goto done;
+			break;
+	}
+	if (sf != NULL) {
+		SLIST_REMOVE_HEAD(&sf_freelist.sf_head, free_list);
+		sf->m = m;
+		nsfbufsused++;
+		nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
+		pmap_qenter(sf->kva, &sf->m, 1);
 	}
-	TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
-	if (sf->m != NULL)
-		LIST_REMOVE(sf, list_entry);
-	LIST_INSERT_HEAD(hash_list, sf, list_entry);
-	sf->ref_count = 1;
-	sf->m = m;
-	nsfbufsused++;
-	nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
-	pmap_qenter(sf->kva, &sf->m, 1);
-done:
-	mtx_unlock(&sf_buf_lock);
+	mtx_unlock(&sf_freelist.sf_lock);
 	return (sf);
 }
 
 /*
- * Free the sf_buf.  In fact, do nothing because there are no resources
- * associated with the sf_buf.
+ * Release resources back to the system.
  */
 void
 sf_buf_free(struct sf_buf *sf)
 {
-	mtx_lock(&sf_buf_lock);
-	sf->ref_count--;
-	/*
-	 * Make sure all changes in KVA end up in physical memory
-	 */
-	mips_dcache_wbinv_range(sf->kva, PAGE_SIZE);
-	if (sf->ref_count == 0) {
-		TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
-		nsfbufsused--;
-		if (sf_buf_alloc_want > 0)
-			wakeup_one(&sf_buf_freelist);
-	}
-	mtx_unlock(&sf_buf_lock);
+
+	pmap_qremove(sf->kva, 1);
+	mtx_lock(&sf_freelist.sf_lock);
+	SLIST_INSERT_HEAD(&sf_freelist.sf_head, sf, free_list);
+	nsfbufsused--;
+	if (sf_buf_alloc_want > 0)
+		wakeup_one(&sf_freelist);
+	mtx_unlock(&sf_freelist.sf_lock);
 }
 
 /*

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