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From: NeilBrown <neilb@suse.com>
To: Oleg Drokin <oleg.drokin@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	James Simmons <jsimmons@infradead.org>,
	Andreas Dilger <andreas.dilger@intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Lustre Development List <lustre-devel@lists.lustre.org>
Subject: [PATCH 07/10] staging: lustre: llite: remove redundant lookup in dump_pgcache
Date: Mon, 07 May 2018 10:54:48 +1000	[thread overview]
Message-ID: <152565448820.30131.5319309021208024337.stgit@noble> (raw)
In-Reply-To: <152565436690.30131.2229703651041382739.stgit@noble>

Both the 'next' and the 'show' functions for the dump_page_cache
seqfile perform a lookup based on the current file index.  This is
needless duplication.

The reason appears to be that the state that needs to be communicated
from "next" to "show" is two pointers, but seq_file only provides for
a single pointer to be returned from next and passed to show.

So make use of the new 'seq_private' structure to store the extra
pointer.
So when 'next' (or 'start') find something, it returns the page and
stores the clob in the private area.
'show' accepts the page as an argument, and finds the clob where it
was stored.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 drivers/staging/lustre/lustre/llite/vvp_dev.c |   98 ++++++++++---------------
 1 file changed, 41 insertions(+), 57 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/vvp_dev.c b/drivers/staging/lustre/lustre/llite/vvp_dev.c
index 183ea3d0f336..8bda51fd97a2 100644
--- a/drivers/staging/lustre/lustre/llite/vvp_dev.c
+++ b/drivers/staging/lustre/lustre/llite/vvp_dev.c
@@ -394,6 +394,7 @@ struct seq_private {
 	struct ll_sb_info	*sbi;
 	struct lu_env		*env;
 	u16			refcheck;
+	struct cl_object	*clob;
 };
 
 static void vvp_pgcache_id_unpack(loff_t pos, struct vvp_pgcache_id *id)
@@ -458,19 +459,20 @@ static struct cl_object *vvp_pgcache_obj(const struct lu_env *env,
 	return NULL;
 }
 
-static loff_t vvp_pgcache_find(const struct lu_env *env,
-			       struct lu_device *dev, loff_t pos)
+static struct page *vvp_pgcache_find(const struct lu_env *env,
+				     struct lu_device *dev,
+				     struct cl_object **clobp, loff_t *pos)
 {
 	struct cl_object     *clob;
 	struct lu_site       *site;
 	struct vvp_pgcache_id id;
 
 	site = dev->ld_site;
-	vvp_pgcache_id_unpack(pos, &id);
+	vvp_pgcache_id_unpack(*pos, &id);
 
 	while (1) {
 		if (id.vpi_bucket >= CFS_HASH_NHLIST(site->ls_obj_hash))
-			return ~0ULL;
+			return NULL;
 		clob = vvp_pgcache_obj(env, dev, &id);
 		if (clob) {
 			struct inode *inode = vvp_object_inode(clob);
@@ -482,20 +484,22 @@ static loff_t vvp_pgcache_find(const struct lu_env *env,
 			if (nr > 0) {
 				id.vpi_index = vmpage->index;
 				/* Cant support over 16T file */
-				nr = !(vmpage->index > 0xffffffff);
+				if (vmpage->index <= 0xffffffff) {
+					*clobp = clob;
+					*pos = vvp_pgcache_id_pack(&id);
+					return vmpage;
+				}
 				put_page(vmpage);
 			}
 
 			lu_object_ref_del(&clob->co_lu, "dump", current);
 			cl_object_put(env, clob);
-			if (nr > 0)
-				return vvp_pgcache_id_pack(&id);
 		}
 		/* to the next object. */
 		++id.vpi_depth;
 		id.vpi_depth &= 0xf;
 		if (id.vpi_depth == 0 && ++id.vpi_bucket == 0)
-			return ~0ULL;
+			return NULL;
 		id.vpi_index = 0;
 	}
 }
@@ -538,72 +542,52 @@ static void vvp_pgcache_page_show(const struct lu_env *env,
 static int vvp_pgcache_show(struct seq_file *f, void *v)
 {
 	struct seq_private	*priv = f->private;
-	loff_t		   pos;
-	struct cl_object	*clob;
-	struct vvp_pgcache_id    id;
-
-	pos = *(loff_t *)v;
-	vvp_pgcache_id_unpack(pos, &id);
-	clob = vvp_pgcache_obj(priv->env, &priv->sbi->ll_cl->cd_lu_dev, &id);
-	if (clob) {
-		struct inode *inode = vvp_object_inode(clob);
-		struct cl_page *page = NULL;
-		struct page *vmpage;
-		int result;
-
-		result = find_get_pages_contig(inode->i_mapping,
-					       id.vpi_index, 1,
-					       &vmpage);
-		if (result > 0) {
-			lock_page(vmpage);
-			page = cl_vmpage_page(vmpage, clob);
-			unlock_page(vmpage);
-			put_page(vmpage);
-		}
-
-		seq_printf(f, "%8x@" DFID ": ", id.vpi_index,
-			   PFID(lu_object_fid(&clob->co_lu)));
-		if (page) {
-			vvp_pgcache_page_show(priv->env, f, page);
-			cl_page_put(priv->env, page);
-		} else {
-			seq_puts(f, "missing\n");
-		}
-		lu_object_ref_del(&clob->co_lu, "dump", current);
-		cl_object_put(priv->env, clob);
+	struct page		*vmpage = v;
+	struct cl_page		*page;
+
+	seq_printf(f, "%8lx@" DFID ": ", vmpage->index,
+		   PFID(lu_object_fid(&priv->clob->co_lu)));
+	lock_page(vmpage);
+	page = cl_vmpage_page(vmpage, priv->clob);
+	unlock_page(vmpage);
+	put_page(vmpage);
+
+	if (page) {
+		vvp_pgcache_page_show(priv->env, f, page);
+		cl_page_put(priv->env, page);
 	} else {
-		seq_printf(f, "%llx missing\n", pos);
+		seq_puts(f, "missing\n");
 	}
+	lu_object_ref_del(&priv->clob->co_lu, "dump", current);
+	cl_object_put(priv->env, priv->clob);
+
 	return 0;
 }
 
 static void *vvp_pgcache_start(struct seq_file *f, loff_t *pos)
 {
 	struct seq_private	*priv = f->private;
+	struct page *ret;
 
 	if (priv->sbi->ll_site->ls_obj_hash->hs_cur_bits >
-	    64 - PGC_OBJ_SHIFT) {
-		pos = ERR_PTR(-EFBIG);
-	} else {
-		*pos = vvp_pgcache_find(priv->env, &priv->sbi->ll_cl->cd_lu_dev,
-					*pos);
-		if (*pos == ~0ULL)
-			pos = NULL;
-	}
+	    64 - PGC_OBJ_SHIFT)
+		ret = ERR_PTR(-EFBIG);
+	else
+		ret = vvp_pgcache_find(priv->env, &priv->sbi->ll_cl->cd_lu_dev,
+				       &priv->clob, pos);
 
-	return pos;
+	return ret;
 }
 
 static void *vvp_pgcache_next(struct seq_file *f, void *v, loff_t *pos)
 {
 	struct seq_private *priv = f->private;
+	struct page *ret;
 
-	*pos = vvp_pgcache_find(priv->env, &priv->sbi->ll_cl->cd_lu_dev,
-				*pos + 1);
-	if (*pos == ~0ULL)
-		pos = NULL;
-
-	return pos;
+	*pos += 1;
+	ret = vvp_pgcache_find(priv->env, &priv->sbi->ll_cl->cd_lu_dev,
+			       &priv->clob, pos);
+	return ret;
 }
 
 static void vvp_pgcache_stop(struct seq_file *f, void *v)

  parent reply	other threads:[~2018-05-07  0:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-07  0:54 [PATCH 00/10 - v2] staging: lustre: assorted improvements NeilBrown
2018-05-07  0:54 ` [PATCH 08/10] staging: lustre: move misc-device registration closer to related code NeilBrown
2018-05-07  0:54 ` NeilBrown [this message]
2018-05-07  0:54 ` [PATCH 01/10] staging: lustre: ldlm: store name directly in namespace NeilBrown
2018-05-07  0:54 ` [PATCH 03/10] staging: lustre: lu_object: discard extra lru count NeilBrown
2018-05-07  0:54 ` [PATCH 02/10] staging: lustre: make struct lu_site_bkt_data private NeilBrown
2018-05-07  0:54 ` [PATCH 06/10] staging: lustre: llite: use more private data in dump_pgcache NeilBrown
2018-05-07  0:54 ` [PATCH 10/10] staging: lustre: fix error deref in ll_splice_alias() NeilBrown
2018-05-07  0:54 ` [PATCH 05/10] staging: lustre: fold lu_object_new() into lu_object_find_at() NeilBrown
2018-05-07  0:54 ` [PATCH 09/10] staging: lustre: move remaining code from linux-module.c to module.c NeilBrown
2018-05-07  0:54 ` [PATCH 04/10] staging: lustre: lu_object: move retry logic inside htable_lookup NeilBrown
  -- strict thread matches above, loose matches on Subject: below --
2018-05-01  3:52 [PATCH 00/10] staging: lustre: assorted improvements NeilBrown
2018-05-01  3:52 ` [PATCH 07/10] staging: lustre: llite: remove redundant lookup in dump_pgcache NeilBrown

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