The patch titled
reduce large do_mount stack usage with noinlines
has been added to the -mm tree. Its filename is
reduce-large-do_mount-stack-usage-with-noinlines.patch
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------------------------------------------------------
Subject: reduce large do_mount stack usage with noinlines
From: Eric Sandeen <sandeen@xxxxxxxxxx>
do_mount() uses a whopping 616 bytes of stack on x86_64 in 2.6.24-mm1,
largely thanks to gcc inlining the various helper functions.
noinlining these can slim it down a lot; on my box this patch gets it down
to 168, which is mostly the struct nameidata nd; left on the stack.
These functions are called only as do_mount() helpers; none of them should
be in any path that would see a performance benefit from inlining...
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/namespace.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff -puN fs/namespace.c~reduce-large-do_mount-stack-usage-with-noinlines fs/namespace.c
--- a/fs/namespace.c~reduce-large-do_mount-stack-usage-with-noinlines
+++ a/fs/namespace.c
@@ -1295,8 +1295,9 @@ out_unlock:
/*
* recursively change the type of the mountpoint.
+ * noinline this do_mount helper to save do_mount stack space.
*/
-static int do_change_type(struct nameidata *nd, int flag)
+static noinline int do_change_type(struct nameidata *nd, int flag)
{
struct vfsmount *m, *mnt = nd->path.mnt;
int recurse = flag & MS_REC;
@@ -1319,8 +1320,10 @@ static int do_change_type(struct nameida
/*
* do loopback mount.
+ * noinline this do_mount helper to save do_mount stack space.
*/
-static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
+static noinline int do_loopback(struct nameidata *nd, char *old_name,
+ int recurse)
{
struct nameidata old_nd;
struct vfsmount *mnt = NULL;
@@ -1386,8 +1389,9 @@ static int change_mount_flags(struct vfs
* change filesystem flags. dir should be a physical root of filesystem.
* If you've mounted a non-root directory somewhere and want to do remount
* on it - tough luck.
+ * noinline this do_mount helper to save do_mount stack space.
*/
-static int do_remount(struct nameidata *nd, int flags, int mnt_flags,
+static noinline int do_remount(struct nameidata *nd, int flags, int mnt_flags,
void *data)
{
int err;
@@ -1425,7 +1429,10 @@ static inline int tree_contains_unbindab
return 0;
}
-static int do_move_mount(struct nameidata *nd, char *old_name)
+/*
+ * noinline this do_mount helper to save do_mount stack space.
+ */
+static noinline int do_move_mount(struct nameidata *nd, char *old_name)
{
struct nameidata old_nd, parent_nd;
struct vfsmount *p;
@@ -1504,8 +1511,9 @@ out:
/*
* create a new mount for userspace and request it to be added into the
* namespace's tree
+ * noinline this do_mount helper to save do_mount stack space.
*/
-static int do_new_mount(struct nameidata *nd, char *type, int flags,
+static noinline int do_new_mount(struct nameidata *nd, char *type, int flags,
int mnt_flags, char *name, void *data)
{
struct vfsmount *mnt;
_
Patches currently in -mm which might be from sandeen@xxxxxxxxxx are
origin.patch
ext2-change-the-default-behaviour-on-error.patch
address-hfs-on-disk-corruption-robustness-review-comments.patch
ecryptfs-make-show_options-reflect-actual-mount-options.patch
ecryptfs-remove-debug-as-mount-option-and-warn-if-set-via-modprobe.patch
ecryptfs-check-for-existing-key_tfm-at-mount-time.patch
ext3-change-the-default-behaviour-on-error.patch
reduce-large-do_mount-stack-usage-with-noinlines.patch
-
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