[lustre-devel] [PATCH 11/25] lustre: llite: Remove transient page counting

[James Simmons]

From: Patrick Farrell <farr0186 at gmail.com>

Transient page counting is not used for anything, as
already noted in the commit message, but costs something
like 4% of the time in DIO page submission.

Remove it.

mpirun -np 1  $IOR -w -r -t 64M -b 64G -o ./iorfile --posix.odirect

This patch reduces i/o time in ms/GiB by:
Write: 6 ms/GiB
Read: 11 ms/GiB

Totals:
Write: 174 ms/GiB
Read: 167 ms/GiB

With previous patches in series:
write     5703 MiB/s
read      5756 MiB/s

Plus this patch:
write     5900 MiB/s
read      6136 MiB/s

WC-bug-id: https://jira.whamcloud.com/browse/LU-13799
Lustre-commit: 587e5aa8342980f7 ("LU-13799 llite: Remove transient page counting")
Signed-off-by: Patrick Farrell <farr0186 at gmail.com>
Reviewed-on: https://review.whamcloud.com/39441
Reviewed-by: Wang Shilong <wshilong at whamcloud.com>
Reviewed-by: Alexey Lyashkov <alexey.lyashkov at hpe.com>
Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
Signed-off-by: James Simmons <jsimmons at infradead.org>
---
 fs/lustre/llite/vvp_internal.h | 7 -------
 fs/lustre/llite/vvp_object.c   | 4 +---
 fs/lustre/llite/vvp_page.c     | 5 -----
 3 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/fs/lustre/llite/vvp_internal.h b/fs/lustre/llite/vvp_internal.h
index f2599be..b5e1df2 100644
--- a/fs/lustre/llite/vvp_internal.h
+++ b/fs/lustre/llite/vvp_internal.h
@@ -189,13 +189,6 @@ struct vvp_object {
 	struct inode	       *vob_inode;
 
 	/**
-	 * Number of transient pages.  This is no longer protected by i_sem,
-	 * and needs to be atomic.  This is not actually used for anything,
-	 * and can probably be removed.
-	 */
-	atomic_t		vob_transient_pages;
-
-	/**
 	 * Number of outstanding mmaps on this file.
 	 *
 	 * \see ll_vm_open(), ll_vm_close().
diff --git a/fs/lustre/llite/vvp_object.c b/fs/lustre/llite/vvp_object.c
index 096d996..294df88 100644
--- a/fs/lustre/llite/vvp_object.c
+++ b/fs/lustre/llite/vvp_object.c
@@ -63,8 +63,7 @@ static int vvp_object_print(const struct lu_env *env, void *cookie,
 	struct inode *inode = obj->vob_inode;
 	struct ll_inode_info *lli;
 
-	(*p)(env, cookie, "(%d %d) inode: %p ",
-	     atomic_read(&obj->vob_transient_pages),
+	(*p)(env, cookie, "(%d) inode: %p ",
 	     atomic_read(&obj->vob_mmap_cnt), inode);
 	if (inode) {
 		lli = ll_i2info(inode);
@@ -228,7 +227,6 @@ static int __vvp_object_init(const struct lu_env *env,
 			     const struct cl_object_conf *conf)
 {
 	vob->vob_inode = conf->coc_inode;
-	atomic_set(&vob->vob_transient_pages, 0);
 	cl_object_page_init(&vob->vob_cl, sizeof(struct vvp_page));
 	return 0;
 }
diff --git a/fs/lustre/llite/vvp_page.c b/fs/lustre/llite/vvp_page.c
index 2ecd414..9e14898 100644
--- a/fs/lustre/llite/vvp_page.c
+++ b/fs/lustre/llite/vvp_page.c
@@ -437,10 +437,8 @@ static void vvp_transient_page_fini(const struct lu_env *env,
 				    struct pagevec *pvec)
 {
 	struct vvp_page *vpg = cl2vvp_page(slice);
-	struct vvp_object *clobj = cl2vvp(slice->cpl_obj);
 
 	vvp_page_fini_common(vpg, pvec);
-	atomic_dec(&clobj->vob_transient_pages);
 }
 
 static const struct cl_page_operations vvp_transient_page_ops = {
@@ -469,11 +467,8 @@ int vvp_page_init(const struct lu_env *env, struct cl_object *obj,
 		cl_page_slice_add(page, &vpg->vpg_cl, obj,
 				  &vvp_page_ops);
 	} else {
-		struct vvp_object *clobj = cl2vvp(obj);
-
 		cl_page_slice_add(page, &vpg->vpg_cl, obj,
 				  &vvp_transient_page_ops);
-		atomic_inc(&clobj->vob_transient_pages);
 	}
 	return 0;
 }
-- 
1.8.3.1