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kernfs: Allocating memory for kernfs_iattrs with kmem_cache. 

Creating a new cache for kernfs_iattrs.
Currently, memory is allocated with kzalloc() which
always gives aligned memory. On ARM, this is 64 byte aligned.
To avoid the wastage of memory in aligning the size requested,
a new cache for kernfs_iattrs is created.

Size of struct kernfs_iattrs is 80 Bytes.
On ARM, it will come in kmalloc-128 slab.
and it will come in kmalloc-192 slab if debug info is enabled.
Extra bytes taken 48 bytes.

Total number of objects created : 4096
Total saving = 48*4096 = 192 KB

After creating new slab(When debug info is enabled) :
sh-3.2# cat /proc/slabinfo
...
kernfs_iattrs_cache   4069   4096    128   32    1 : tunables    0    0    0 : slabdata    128    128      0
...

All testing has been done on ARM target.

Signed-off-by: Ayush Mittal <ayush.m@samsung.com>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ayush Mittal 2019-02-06 10:25:42 +05:30 committed by Greg Kroah-Hartman
parent 5b2f2bd62e
commit 26e28d68b1
4 changed files with 9 additions and 4 deletions
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2
fs/kernfs/dir.c
View File

@ -536,8 +536,8 @@ void kernfs_put(struct kernfs_node *kn)
security_release_secctx(kn->iattr->ia_secdata,
kn->iattr->ia_secdata_len);
simple_xattrs_free(&kn->iattr->xattrs);
kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
}
kfree(kn->iattr);
spin_lock(&kernfs_idr_lock);
idr_remove(&root->ino_idr, kn->id.ino);
spin_unlock(&kernfs_idr_lock);

2
fs/kernfs/inode.c
View File

@ -42,7 +42,7 @@ static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
if (kn->iattr)
goto out_unlock;
kn->iattr = kzalloc(sizeof(struct kernfs_iattrs), GFP_KERNEL);
kn->iattr = kmem_cache_zalloc(kernfs_iattrs_cache, GFP_KERNEL);
if (!kn->iattr)
goto out_unlock;
iattrs = &kn->iattr->ia_iattr;

2
fs/kernfs/kernfs-internal.h
View File

@ -78,7 +78,7 @@ static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry)
}
extern const struct super_operations kernfs_sops;
extern struct kmem_cache *kernfs_node_cache;
extern struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
/*
* inode.c

7
fs/kernfs/mount.c
View File

@ -20,7 +20,7 @@
#include "kernfs-internal.h"
struct kmem_cache *kernfs_node_cache;
struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data)
{
@ -417,4 +417,9 @@ void __init kernfs_init(void)
0,
SLAB_PANIC | SLAB_TYPESAFE_BY_RCU,
NULL);
/* Creates slab cache for kernfs inode attributes */
kernfs_iattrs_cache = kmem_cache_create("kernfs_iattrs_cache",
sizeof(struct kernfs_iattrs),
0, SLAB_PANIC, NULL);
}