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 <[email protected]> Signed-off-by: Vaneet Narang <[email protected]> --- v1 -> v2: Changed slab creation flag. fs/kernfs/dir.c | 2 +- fs/kernfs/inode.c | 2 +- fs/kernfs/kernfs-internal.h | 2 +- fs/kernfs/mount.c | 7 ++++++- 4 files changed, 9 insertions(+), 4 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 4ca0b5c..b84d635 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -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); diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index 80cebcd..0c1fd94 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -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; diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 3d83b11..dba810c 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -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 diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index fdf527b..450eb38 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -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); } -- 1.9.1
