On 6/13/2013 8:29 AM, Tomasz Stanislawski wrote: > On ARM, sizeof(struct smack_rule)==20. Allocation by kmalloc() uses a > 32-byte-long chunk to allocate 20 bytes. Just ask ksize(). It means that 40% > of memory is simply wasted for padding bytes. > > The problem is fixed in this patch by using kmem_cache. The cache allocates > struct smack_rule using 24-byte-long chunks according to ksize(). This reduces > amount of used memory by 25%.
I'm not opposed to this change, but could I see some performance numbers to justify it? In particular, I'm concerned about the rules load impact. > Signed-off-by: Tomasz Stanislawski <[email protected]> > --- > security/smack/smack.h | 3 +++ > security/smack/smack_lsm.c | 11 ++++++++++- > security/smack/smackfs.c | 2 +- > 3 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/security/smack/smack.h b/security/smack/smack.h > index 8ad3095..38ba673 100644 > --- a/security/smack/smack.h > +++ b/security/smack/smack.h > @@ -233,6 +233,9 @@ extern struct mutex smack_known_lock; > extern struct list_head smack_known_list; > extern struct list_head smk_netlbladdr_list; > > +/* Cache for fast and thrifty allocations */ > +extern struct kmem_cache *smack_rule_cache; > + > extern struct security_operations smack_ops; > > /* > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index d52c780..7aa696a 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -3564,6 +3564,9 @@ static __init void init_smack_known_list(void) > list_add(&smack_known_web.list, &smack_known_list); > } > > +/* KMEM caches for fast and thrifty allocations */ > +struct kmem_cache *smack_rule_cache; > + > /** > * smack_init - initialize the smack system > * > @@ -3577,10 +3580,16 @@ static __init int smack_init(void) > if (!security_module_enable(&smack_ops)) > return 0; > > + smack_rule_cache = KMEM_CACHE(smack_rule, 0); > + if (!smack_rule_cache) > + return -ENOMEM; > + > tsp = new_task_smack(smack_known_floor.smk_known, > smack_known_floor.smk_known, GFP_KERNEL); > - if (tsp == NULL) > + if (tsp == NULL) { > + kmem_cache_destroy(smack_rule_cache); > return -ENOMEM; > + } > > printk(KERN_INFO "Smack: Initializing.\n"); > > diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c > index e8c57f3..c08b1ec 100644 > --- a/security/smack/smackfs.c > +++ b/security/smack/smackfs.c > @@ -217,7 +217,7 @@ static int smk_set_access(struct smack_parsed_rule *srp, > } > > if (found == 0) { > - sp = kzalloc(sizeof(*sp), GFP_KERNEL); > + sp = kmem_cache_zalloc(smack_rule_cache, GFP_KERNEL); > if (sp == NULL) { > rc = -ENOMEM; > goto out; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
