From 846e463a70e910f2a831aea19f9a361422a2ff5b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 7 Oct 2020 09:51:11 -0700 Subject: net/sched: get rid of qdisc->padded kmalloc() of sufficiently big portion of memory is cache-aligned in regular conditions. If some debugging options are used, there is no reason qdisc structures would need 64-byte alignment if most other kernel structures are not aligned. This get rid of QDISC_ALIGN and QDISC_ALIGNTO. Addition of privdata field will help implementing the reverse of qdisc_priv() and documents where the private data is. Signed-off-by: Eric Dumazet Cc: Allen Pais Acked-by: Cong Wang Signed-off-by: Jakub Kicinski --- include/net/pkt_sched.h | 5 +---- include/net/sch_generic.h | 5 ++++- net/sched/sch_generic.c | 23 +++++------------------ 3 files changed, 10 insertions(+), 23 deletions(-) diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h index ac8c890a2657..4ed32e6b0201 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -19,12 +19,9 @@ struct qdisc_walker { int (*fn)(struct Qdisc *, unsigned long cl, struct qdisc_walker *); }; -#define QDISC_ALIGNTO 64 -#define QDISC_ALIGN(len) (((len) + QDISC_ALIGNTO-1) & ~(QDISC_ALIGNTO-1)) - static inline void *qdisc_priv(struct Qdisc *q) { - return (char *) q + QDISC_ALIGN(sizeof(struct Qdisc)); + return &q->privdata; } /* diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 6c762457122f..d8fd8676fc72 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -91,7 +91,7 @@ struct Qdisc { struct net_rate_estimator __rcu *rate_est; struct gnet_stats_basic_cpu __percpu *cpu_bstats; struct gnet_stats_queue __percpu *cpu_qstats; - int padded; + int pad; refcount_t refcnt; /* @@ -112,6 +112,9 @@ struct Qdisc { /* for NOLOCK qdisc, true if there are no enqueued skbs */ bool empty; struct rcu_head rcu; + + /* private data */ + long privdata[] ____cacheline_aligned; }; static inline void qdisc_refcount_inc(struct Qdisc *qdisc) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 54c417244642..49eae93d1489 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -802,9 +802,8 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, const struct Qdisc_ops *ops, struct netlink_ext_ack *extack) { - void *p; struct Qdisc *sch; - unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size; + unsigned int size = sizeof(*sch) + ops->priv_size; int err = -ENOBUFS; struct net_device *dev; @@ -815,22 +814,10 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, } dev = dev_queue->dev; - p = kzalloc_node(size, GFP_KERNEL, - netdev_queue_numa_node_read(dev_queue)); + sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue)); - if (!p) + if (!sch) goto errout; - sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p); - /* if we got non aligned memory, ask more and do alignment ourself */ - if (sch != p) { - kfree(p); - p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL, - netdev_queue_numa_node_read(dev_queue)); - if (!p) - goto errout; - sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p); - sch->padded = (char *) sch - (char *) p; - } __skb_queue_head_init(&sch->gso_skb); __skb_queue_head_init(&sch->skb_bad_txq); qdisc_skb_head_init(&sch->q); @@ -873,7 +860,7 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, return sch; errout1: - kfree(p); + kfree(sch); errout: return ERR_PTR(err); } @@ -941,7 +928,7 @@ void qdisc_free(struct Qdisc *qdisc) free_percpu(qdisc->cpu_qstats); } - kfree((char *) qdisc - qdisc->padded); + kfree(qdisc); } static void qdisc_free_cb(struct rcu_head *head) -- cgit v1.2.3