Move the "tfm" field in struct zswap_pool to the top, after the "zpool"
field.
As suggested by Sergey Senozhatsky:
>> > ->tfm will be access pretty often, right? did you intentionally put it
>> > at the bottom offset of `struct zswap_pool'?
>>
>> no it wasn't intentional; does moving it up provide a benefit?
>
> well, I just prefer to keep 'read mostly' pointers together. all
> those cache lines, etc.
>
> gcc 5.1, x86_64
>
> struct zswap_pool {
> struct zpool *zpool;
> + struct crypto_comp * __percpu *tfm;
> struct kref kref;
> struct list_head list;
> struct rcu_head rcu_head;
> struct notifier_block notifier;
> char tfm_name[CRYPTO_MAX_ALG_NAME];
> - struct crypto_comp * __percpu *tfm;
> };
>
> ../scripts/bloat-o-meter zswap.o.old zswap.o
> add/remove: 0/0 grow/shrink: 0/6 up/down: 0/-27 (-27)
> function old new delta
> zswap_writeback_entry 659 656 -3
> zswap_frontswap_store 1445 1442 -3
> zswap_frontswap_load 417 414 -3
> zswap_pool_create 438 432 -6
> __zswap_cpu_comp_notifier.part 152 146 -6
> __zswap_cpu_comp_notifier 122 116 -6
Suggested-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Dan Streetman <[email protected]>
---
mm/zswap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/zswap.c b/mm/zswap.c
index b198081..4043df7 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -120,12 +120,12 @@ module_param_named(max_pool_percent,
zswap_max_pool_percent, uint, 0644);
struct zswap_pool {
struct zpool *zpool;
+ struct crypto_comp * __percpu *tfm;
struct kref kref;
struct list_head list;
struct rcu_head rcu_head;
struct notifier_block notifier;
char tfm_name[CRYPTO_MAX_ALG_NAME];
- struct crypto_comp * __percpu *tfm;
};
/*
--
2.1.0
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