1 files changed, 172 insertions, 0 deletions

diff --git a/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.2/0075-dcache-use-a-dispose-list-in-select_parent.patch b/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.2/0075-dcache-use-a-dispose-list-in-select_parent.patch
new file mode 100644
index 00000000..d369d7a3
--- /dev/null
+++ b/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.2/0075-dcache-use-a-dispose-list-in-select_parent.patch
@@ -0,0 +1,172 @@
+From 48a7a2bae38f29f5b231f460dd2852e00e50d549 Mon Sep 17 00:00:00 2001
+From: Dave Chinner <david@fromorbit.com>
+Date: Tue, 23 Aug 2011 18:56:24 +1000
+Subject: [PATCH 075/130] dcache: use a dispose list in select_parent
+
+commit b48f03b319ba78f3abf9a7044d1f436d8d90f4f9 upstream.
+
+select_parent currently abuses the dentry cache LRU to provide
+cleanup features for child dentries that need to be freed. It moves
+them to the tail of the LRU, then tells shrink_dcache_parent() to
+calls __shrink_dcache_sb to unconditionally move them to a dispose
+list (as DCACHE_REFERENCED is ignored). __shrink_dcache_sb() has to
+relock the dentries to move them off the LRU onto the dispose list,
+but otherwise does not touch the dentries that select_parent() moved
+to the tail of the LRU. It then passses the dispose list to
+shrink_dentry_list() which tries to free the dentries.
+
+IOWs, the use of __shrink_dcache_sb() is superfluous - we can build
+exactly the same list of dentries for disposal directly in
+select_parent() and call shrink_dentry_list() instead of calling
+__shrink_dcache_sb() to do that. This means that we avoid long holds
+on the lru lock walking the LRU moving dentries to the dispose list
+We also avoid the need to relock each dentry just to move it off the
+LRU, reducing the numebr of times we lock each dentry to dispose of
+them in shrink_dcache_parent() from 3 to 2 times.
+
+Further, we remove one of the two callers of __shrink_dcache_sb().
+This also means that __shrink_dcache_sb can be moved into back into
+prune_dcache_sb() and we no longer have to handle referenced
+dentries conditionally, simplifying the code.
+
+Signed-off-by: Dave Chinner <dchinner@redhat.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
+---
+ fs/dcache.c |   63 +++++++++++++++++++---------------------------------------
+ 1 files changed, 21 insertions(+), 42 deletions(-)
+
+diff --git a/fs/dcache.c b/fs/dcache.c
+index 89509b5..108116e 100644
+--- a/fs/dcache.c
++++ b/fs/dcache.c
+@@ -275,15 +275,15 @@ static void dentry_lru_prune(struct dentry *dentry)
+        }
+ }
+ 
+-static void dentry_lru_move_tail(struct dentry *dentry)
++static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list)
+ {
+        spin_lock(&dcache_lru_lock);
+        if (list_empty(&dentry->d_lru)) {
+-               list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
++               list_add_tail(&dentry->d_lru, list);
+                dentry->d_sb->s_nr_dentry_unused++;
+                dentry_stat.nr_unused++;
+        } else {
+-               list_move_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
++               list_move_tail(&dentry->d_lru, list);
+        }
+        spin_unlock(&dcache_lru_lock);
+ }
+@@ -769,14 +769,18 @@ static void shrink_dentry_list(struct list_head *list)
+ }
+ 
+ /**
+- * __shrink_dcache_sb - shrink the dentry LRU on a given superblock
+- * @sb:                superblock to shrink dentry LRU.
+- * @count:     number of entries to prune
+- * @flags:     flags to control the dentry processing
++ * prune_dcache_sb - shrink the dcache
++ * @sb: superblock
++ * @count: number of entries to try to free
++ *
++ * Attempt to shrink the superblock dcache LRU by @count entries. This is
++ * done when we need more memory an called from the superblock shrinker
++ * function.
+  *
+- * If flags contains DCACHE_REFERENCED reference dentries will not be pruned.
++ * This function may fail to free any resources if all the dentries are in
++ * use.
+  */
+-static void __shrink_dcache_sb(struct super_block *sb, int count, int flags)
++void prune_dcache_sb(struct super_block *sb, int count)
+ {
+        struct dentry *dentry;
+        LIST_HEAD(referenced);
+@@ -795,13 +799,7 @@ relock:
+                        goto relock;
+                }
+ 
+-               /*
+-                * If we are honouring the DCACHE_REFERENCED flag and the
+-                * dentry has this flag set, don't free it.  Clear the flag
+-                * and put it back on the LRU.
+-                */
+-               if (flags & DCACHE_REFERENCED &&
+-                               dentry->d_flags & DCACHE_REFERENCED) {
++               if (dentry->d_flags & DCACHE_REFERENCED) {
+                        dentry->d_flags &= ~DCACHE_REFERENCED;
+                        list_move(&dentry->d_lru, &referenced);
+                        spin_unlock(&dentry->d_lock);
+@@ -821,23 +819,6 @@ relock:
+ }
+ 
+ /**
+- * prune_dcache_sb - shrink the dcache
+- * @sb: superblock
+- * @nr_to_scan: number of entries to try to free
+- *
+- * Attempt to shrink the superblock dcache LRU by @nr_to_scan entries. This is
+- * done when we need more memory an called from the superblock shrinker
+- * function.
+- *
+- * This function may fail to free any resources if all the dentries are in
+- * use.
+- */
+-void prune_dcache_sb(struct super_block *sb, int nr_to_scan)
+-{
+-       __shrink_dcache_sb(sb, nr_to_scan, DCACHE_REFERENCED);
+-}
+-
+-/**
+  * shrink_dcache_sb - shrink dcache for a superblock
+  * @sb: superblock
+  *
+@@ -1091,7 +1072,7 @@ EXPORT_SYMBOL(have_submounts);
+  * drop the lock and return early due to latency
+  * constraints.
+  */
+-static int select_parent(struct dentry * parent)
++static int select_parent(struct dentry *parent, struct list_head *dispose)
+ {
+        struct dentry *this_parent;
+        struct list_head *next;
+@@ -1113,12 +1094,11 @@ resume:
+ 
+                spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
+ 
+-               /* 
+-                * move only zero ref count dentries to the end 
+-                * of the unused list for prune_dcache
++               /*
++                * move only zero ref count dentries to the dispose list.
+                 */
+                if (!dentry->d_count) {
+-                       dentry_lru_move_tail(dentry);
++                       dentry_lru_move_list(dentry, dispose);
+                        found++;
+                } else {
+                        dentry_lru_del(dentry);
+@@ -1180,14 +1160,13 @@ rename_retry:
+  *
+  * Prune the dcache to remove unused children of the parent dentry.
+  */
+- 
+ void shrink_dcache_parent(struct dentry * parent)
+ {
+-       struct super_block *sb = parent->d_sb;
++       LIST_HEAD(dispose);
+        int found;
+ 
+-       while ((found = select_parent(parent)) != 0)
+-               __shrink_dcache_sb(sb, found, 0);
++       while ((found = select_parent(parent, &dispose)) != 0)
++               shrink_dentry_list(&dispose);
+ }
+ EXPORT_SYMBOL(shrink_dcache_parent);
+ 
+-- 
+1.7.7.4
+