svn commit: r215401 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Andriy Gapon]

Author: avg
Date: Tue Nov 16 15:53:44 2010
New Revision: 215401
URL: http://svn.freebsd.org/changeset/base/215401

Log:
  zfs+sendfile: populate all requested pages, not just those already cached
  
  kern_sendfile() uses vm_rdwr() to read-ahead blocks of data to populate
  page cache.  When sendfile stumbles upon a page that is not populated
  yet, it sends out all the mbufs that it collected so far.  This
  resulted in very poor performance with ZFS when file data is not in the
  page cache, because ZFS vop_read for UIO_NOCOPY case populated only
  those pages that are already in cache, but not valid.  Which means that
  most of the time it populated only the first requested page in the
  described above scenario.
  
  Reported by:	Alexander Zagrebin <alexz at visp.ru>
  Tested by:	Alexander Zagrebin <alexz at visp.ru>,
  		Artemiev Igor <ai at kliksys.ru>
  MFC after:	12 days

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	Tue Nov 16 15:02:53 2010	(r215400)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	Tue Nov 16 15:53:44 2010	(r215401)
@@ -67,6 +67,7 @@
 #include <sys/sf_buf.h>
 #include <sys/sched.h>
 #include <sys/acl.h>
+#include <vm/vm_pageout.h>
 
 /*
  * Programming rules.
@@ -481,7 +482,7 @@ again:
 				uiomove_fromphys(&m, off, bytes, uio);
 			VM_OBJECT_LOCK(obj);
 			vm_page_wakeup(m);
-		} else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) {
+		} else if (uio->uio_segflg == UIO_NOCOPY) {
 			/*
 			 * The code below is here to make sendfile(2) work
 			 * correctly with ZFS. As pointed out by ups@
@@ -491,7 +492,7 @@ again:
 			 */
 			KASSERT(off == 0,
 			    ("unexpected offset in mappedread for sendfile"));
-			if ((m->oflags & VPO_BUSY) != 0) {
+			if (m != NULL && (m->oflags & VPO_BUSY) != 0) {
 				/*
 				 * Reference the page before unlocking and
 				 * sleeping so that the page daemon is less
@@ -501,8 +502,17 @@ again:
 				vm_page_flag_set(m, PG_REFERENCED);
 				vm_page_sleep(m, "zfsmrb");
 				goto again;
+			} else if (m == NULL) {
+				m = vm_page_alloc(obj, OFF_TO_IDX(start),
+				    VM_ALLOC_NOBUSY | VM_ALLOC_NORMAL);
+				if (m == NULL) {
+					VM_OBJECT_UNLOCK(obj);
+					VM_WAIT;
+					VM_OBJECT_LOCK(obj);
+					goto again;
+				}
 			}
-			vm_page_busy(m);
+			vm_page_io_start(m);
 			VM_OBJECT_UNLOCK(obj);
 			if (dirbytes > 0) {
 				error = dmu_read_uio(os, zp->z_id, uio,
@@ -520,7 +530,7 @@ again:
 			VM_OBJECT_LOCK(obj);
 			if (error == 0)
 				m->valid = VM_PAGE_BITS_ALL;
-			vm_page_wakeup(m);
+			vm_page_io_finish(m);
 			if (error == 0) {
 				uio->uio_resid -= bytes;
 				uio->uio_offset += bytes;