svn commit: r266796 - in projects/sendfile/sys: dev/ti kern sys

[Gleb Smirnoff]

Author: glebius
Date: Wed May 28 11:23:44 2014
New Revision: 266796
URL: http://svnweb.freebsd.org/changeset/base/266796

Log:
  Couple of API improvements:
  
  - SF_NOCACHE flag from userland says that when an mbuf is freed, the
    referenced page should go into free pool, instead of being cached
    with associated object.
    This is achieved via alternative ext_free function. While here also
    rename sf_buf_mext() to a more meaningful name.
  
  - Bits above 16 in flags now count number of pages that sendfile(2)
    is allowed to readahead when processing the request.
  
  Sponsored by:	Netflix
  Sponsored by:	Nginx, Inc.

Modified:
  projects/sendfile/sys/dev/ti/if_ti.c
  projects/sendfile/sys/kern/uipc_syscalls.c
  projects/sendfile/sys/sys/sf_buf.h
  projects/sendfile/sys/sys/socket.h

Modified: projects/sendfile/sys/dev/ti/if_ti.c
==============================================================================
--- projects/sendfile/sys/dev/ti/if_ti.c	Wed May 28 10:33:06 2014	(r266795)
+++ projects/sendfile/sys/dev/ti/if_ti.c	Wed May 28 11:23:44 2014	(r266796)
@@ -1629,7 +1629,7 @@ ti_newbuf_jumbo(struct ti_softc *sc, int
 			m[i]->m_data = (void *)sf_buf_kva(sf[i]);
 			m[i]->m_len = PAGE_SIZE;
 			MEXTADD(m[i], sf_buf_kva(sf[i]), PAGE_SIZE,
-			    sf_buf_mext, (void*)sf_buf_kva(sf[i]), sf[i],
+			    sf_mext_free, (void*)sf_buf_kva(sf[i]), sf[i],
 			    0, EXT_DISPOSABLE);
 			m[i]->m_next = m[i+1];
 		}
@@ -1694,7 +1694,7 @@ nobufs:
 		if (m[i])
 			m_freem(m[i]);
 		if (sf[i])
-			sf_buf_mext((void *)sf_buf_kva(sf[i]), sf[i]);
+			sf_mext_free((void *)sf_buf_kva(sf[i]), sf[i]);
 	}
 	return (ENOBUFS);
 }

Modified: projects/sendfile/sys/kern/uipc_syscalls.c
==============================================================================
--- projects/sendfile/sys/kern/uipc_syscalls.c	Wed May 28 10:33:06 2014	(r266795)
+++ projects/sendfile/sys/kern/uipc_syscalls.c	Wed May 28 11:23:44 2014	(r266796)
@@ -1989,7 +1989,7 @@ filt_sfsync(struct knote *kn, long hint)
  * Detach mapped page and release resources back to the system.
  */
 int
-sf_buf_mext(struct mbuf *mb, void *addr, void *args)
+sf_mext_free(struct mbuf *mb, void *addr, void *args)
 {
 	vm_page_t m;
 	struct sendfile_sync *sfs;
@@ -2010,9 +2010,38 @@ sf_buf_mext(struct mbuf *mb, void *addr,
 		sfs = addr;
 		sf_sync_deref(sfs);
 	}
-	/*
-	 * sfs may be invalid at this point, don't use it!
-	 */
+	return (EXT_FREE_OK);
+}
+
+/*
+ * Same as above, but forces the page to be detached from the object
+ * and go into free pool.
+ */
+static int
+sf_mext_free_nocache(struct mbuf *mb, void *addr, void *args)
+{
+	vm_page_t m;
+	struct sendfile_sync *sfs;
+
+	m = sf_buf_page(args);
+	sf_buf_free(args);
+	vm_page_lock(m);
+	vm_page_unwire(m, 0);
+	if (m->wire_count == 0) {
+		vm_object_t obj;
+
+		if ((obj = m->object) == NULL)
+			vm_page_free(m);
+		else if (!vm_page_xbusied(m) && VM_OBJECT_TRYWLOCK(obj)) {
+			vm_page_free(m);
+			VM_OBJECT_WUNLOCK(obj);
+		}
+	}
+	vm_page_unlock(m);
+	if (addr != NULL) {
+		sfs = addr;
+		sf_sync_deref(sfs);
+	}
 	return (EXT_FREE_OK);
 }
 
@@ -3052,8 +3081,10 @@ retry_space:
 		else
 			npages = howmany(space, PAGE_SIZE);
 
+		rhpages = SF_READAHEAD(flags) ?
+		    SF_READAHEAD(flags) : sfreadahead;
 		rhpages = min(howmany(obj_size - (off & ~PAGE_MASK) -
-		    (npages * PAGE_SIZE), PAGE_SIZE), sfreadahead);
+		    (npages * PAGE_SIZE), PAGE_SIZE), rhpages);
 
 		sfio = malloc(sizeof(struct sf_io) +
 		    (rhpages + npages) * sizeof(vm_page_t), M_TEMP, M_WAITOK);
@@ -3101,7 +3132,8 @@ retry_space:
 			 */
 			m0 = m_get(M_WAITOK, MT_DATA);
 			(void )m_extadd(m0, (caddr_t )sf_buf_kva(sf), PAGE_SIZE,
-			    sf_buf_mext, sfs, sf, M_RDONLY, EXT_SFBUF,
+			    (flags & SF_NOCACHE) ? sf_mext_free_nocache :
+			    sf_mext_free, sfs, sf, M_RDONLY, EXT_SFBUF,
 			    M_WAITOK);
 			m0->m_data = (char *)sf_buf_kva(sf) +
 			    (vmoff(i, off) & PAGE_MASK);

Modified: projects/sendfile/sys/sys/sf_buf.h
==============================================================================
--- projects/sendfile/sys/sys/sf_buf.h	Wed May 28 10:33:06 2014	(r266795)
+++ projects/sendfile/sys/sys/sf_buf.h	Wed May 28 11:23:44 2014	(r266796)
@@ -52,7 +52,7 @@ struct sfstat {				/* sendfile statistic
 #include <machine/sf_buf.h>
 #include <sys/systm.h>
 #include <sys/counter.h>
-struct mbuf;	/* for sf_buf_mext() */
+struct mbuf;	/* for sf_mext_free() */
 
 extern counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)];
 #define	SFSTAT_ADD(name, val)	\
@@ -61,6 +61,7 @@ extern counter_u64_t sfstat[sizeof(struc
 #define	SFSTAT_INC(name)	SFSTAT_ADD(name, 1)
 #endif /* _KERNEL */
 
-int	sf_buf_mext(struct mbuf *mb, void *addr, void *args);
+int	sf_mext_free(struct mbuf *mb, void *addr, void *args);
+int	sf_mext_free_nocache(struct mbuf *mb, void *addr, void *args);
 
 #endif /* !_SYS_SF_BUF_H_ */

Modified: projects/sendfile/sys/sys/socket.h
==============================================================================
--- projects/sendfile/sys/sys/socket.h	Wed May 28 10:33:06 2014	(r266795)
+++ projects/sendfile/sys/sys/socket.h	Wed May 28 11:23:44 2014	(r266796)
@@ -602,12 +602,15 @@ struct sf_hdtr_all {
  * Sendfile-specific flag(s)
  */
 #define	SF_NODISKIO     0x00000001
-#define	SF_MNOWAIT	0x00000002
+#define	SF_MNOWAIT	0x00000002	/* unused since 11.0 */
 #define	SF_SYNC		0x00000004
 #define	SF_KQUEUE	0x00000008
+#define	SF_NOCACHE	0x00000010
+#define	SF_FLAGS(rh, flags)	(((rh) << 16) | (flags))
 
 #ifdef _KERNEL
 #define	SFK_COMPAT	0x00000001
+#define	SF_READAHEAD(flags)	((flags) >> 16)
 #endif /* _KERNEL */
 #endif /* __BSD_VISIBLE */