@@ -882,9 +882,8 @@ static void skb_clone_fraglist(struct sk_buff *skb)
#if IS_ENABLED(CONFIG_PAGE_POOL)
bool napi_pp_put_page(struct page *page, bool napi_safe)
{
- struct napi_struct *napi;
+ bool allow_direct = false;
struct page_pool *pp;
- bool allow_direct;
page = compound_head(page);
@@ -904,9 +903,12 @@ bool napi_pp_put_page(struct page *page, bool napi_safe)
* in the same context as the consumer would run, so there's
* no possible race.
*/
- napi = READ_ONCE(pp->p.napi);
- allow_direct = napi_safe && napi &&
- READ_ONCE(napi->list_owner) == smp_processor_id();
+ if (napi_safe) {
+ const struct napi_struct *napi = READ_ONCE(pp->p.napi);
+
+ allow_direct = napi &&
+ READ_ONCE(napi->list_owner) == smp_processor_id();
+ }
/* Driver set this to memory recycling info. Reset it on recycle.
* This will *not* work for NIC using a split-page memory model.
Currently, pp->p.napi is always read, but the actual variable it gets assigned to is read-only when @napi_safe is true. For the !napi_safe cases, which yet is still a pack, it's an unneeded operation. Moreover, it can lead to premature or even redundant page_pool cacheline access. For example, when page_pool_is_last_frag() returns false (with the recent frag improvements). Thus, read it only when @napi_safe is true. This also allows moving @napi inside the condition block itself. Constify it while we are here, because why not. Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com> --- net/core/skbuff.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)