From: Felix Fietkau Date: Wed, 10 Apr 2013 13:11:16 +0000 (+0000) Subject: kernel: add patches by Dave Täht to reduce buffer size in longer queues to reduce... X-Git-Url: http://git.openwrt.org/?p=openwrt%2Fsvn-archive%2Farchive.git;a=commitdiff_plain;h=b7aa97c02f347922e156a3bcbd3a39651759ad40 kernel: add patches by Dave Täht to reduce buffer size in longer queues to reduce memory pressure Signed-off-by: Felix Fietkau SVN-Revision: 36301 --- diff --git a/target/linux/generic/patches-3.8/656-skb_reduce_truesize-helper.patch b/target/linux/generic/patches-3.8/656-skb_reduce_truesize-helper.patch new file mode 100644 index 0000000000..e538eade8d --- /dev/null +++ b/target/linux/generic/patches-3.8/656-skb_reduce_truesize-helper.patch @@ -0,0 +1,41 @@ +From 4593a806e31119c5bd3faa00c7210ad862d515af Mon Sep 17 00:00:00 2001 +From: Dave Taht +Date: Mon, 31 Dec 2012 10:02:21 -0800 +Subject: [PATCH 3/7] skb_reduce_truesize: helper function for shrinking skbs + whenever needed + +On embedded devices in particular, large queues of small packets from the rx +path with a large truesize can exist. Reducing their size can reduce +memory pressure. skb_reduce_truesize is a helper function for doing this, +when needed. +--- + include/linux/skbuff.h | 18 ++++++++++++++++++ + 1 file changed, 18 insertions(+) + +--- a/include/linux/skbuff.h ++++ b/include/linux/skbuff.h +@@ -1772,6 +1772,24 @@ static inline void pskb_trim_unique(stru + BUG_ON(err); + } + ++/* ++ * Caller wants to reduce memory needs before queueing skb ++ * The (expensive) copy should not be be done in fast path. ++ */ ++static inline struct sk_buff *skb_reduce_truesize(struct sk_buff *skb) ++{ ++ if (skb->truesize > 2 * SKB_TRUESIZE(skb->len)) { ++ struct sk_buff *nskb; ++ nskb = skb_copy_expand(skb, skb_headroom(skb), 0, ++ GFP_ATOMIC | __GFP_NOWARN); ++ if (nskb) { ++ __kfree_skb(skb); ++ skb = nskb; ++ } ++ } ++ return skb; ++} ++ + /** + * skb_orphan - orphan a buffer + * @skb: buffer to orphan diff --git a/target/linux/generic/patches-3.8/657-qdisc_reduce_truesize.patch b/target/linux/generic/patches-3.8/657-qdisc_reduce_truesize.patch new file mode 100644 index 0000000000..e27d0a04d6 --- /dev/null +++ b/target/linux/generic/patches-3.8/657-qdisc_reduce_truesize.patch @@ -0,0 +1,63 @@ +From bc9fec2f87d57bdbff30d296605e24504513f65c Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Dave=20T=C3=A4ht?= +Date: Mon, 17 Sep 2012 19:20:22 -0700 +Subject: [PATCH 4/7] net: add skb_reduce_truesize support to common qdiscs + +Reduce skb size under load when queues begin to fill on the +commont qdiscs. +--- + net/sched/sch_codel.c | 2 ++ + net/sched/sch_fifo.c | 12 ++++++++---- + net/sched/sch_fq_codel.c | 2 ++ + 3 files changed, 12 insertions(+), 4 deletions(-) + +--- a/net/sched/sch_codel.c ++++ b/net/sched/sch_codel.c +@@ -96,6 +96,8 @@ static int codel_qdisc_enqueue(struct sk + struct codel_sched_data *q; + + if (likely(qdisc_qlen(sch) < sch->limit)) { ++ if(qdisc_qlen(sch) > 128) ++ skb = skb_reduce_truesize(skb); + codel_set_enqueue_time(skb); + return qdisc_enqueue_tail(skb, sch); + } +--- a/net/sched/sch_fifo.c ++++ b/net/sched/sch_fifo.c +@@ -29,17 +29,21 @@ static int bfifo_enqueue(struct sk_buff + + static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) + { +- if (likely(skb_queue_len(&sch->q) < sch->limit)) ++ if (likely(skb_queue_len(&sch->q) < sch->limit)) { ++ if (skb_queue_len(&sch->q) > 128) ++ skb = skb_reduce_truesize(skb); + return qdisc_enqueue_tail(skb, sch); +- ++ } + return qdisc_reshape_fail(skb, sch); + } + + static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch) + { +- if (likely(skb_queue_len(&sch->q) < sch->limit)) ++ if (likely(skb_queue_len(&sch->q) < sch->limit)) { ++ if (skb_queue_len(&sch->q) > 128) ++ skb = skb_reduce_truesize(skb); + return qdisc_enqueue_tail(skb, sch); +- ++ } + /* queue full, remove one skb to fulfill the limit */ + __qdisc_queue_drop_head(sch, &sch->q); + sch->qstats.drops++; +--- a/net/sched/sch_fq_codel.c ++++ b/net/sched/sch_fq_codel.c +@@ -182,6 +182,8 @@ static int fq_codel_enqueue(struct sk_bu + return ret; + } + idx--; ++ if (sch->q.qlen > 128) ++ skb = skb_reduce_truesize(skb); + + codel_set_enqueue_time(skb); + flow = &q->flows[idx]; diff --git a/target/linux/generic/patches-3.9/656-skb_reduce_truesize-helper.patch b/target/linux/generic/patches-3.9/656-skb_reduce_truesize-helper.patch new file mode 100644 index 0000000000..2b3cfc3d26 --- /dev/null +++ b/target/linux/generic/patches-3.9/656-skb_reduce_truesize-helper.patch @@ -0,0 +1,41 @@ +From 4593a806e31119c5bd3faa00c7210ad862d515af Mon Sep 17 00:00:00 2001 +From: Dave Taht +Date: Mon, 31 Dec 2012 10:02:21 -0800 +Subject: [PATCH 3/7] skb_reduce_truesize: helper function for shrinking skbs + whenever needed + +On embedded devices in particular, large queues of small packets from the rx +path with a large truesize can exist. Reducing their size can reduce +memory pressure. skb_reduce_truesize is a helper function for doing this, +when needed. +--- + include/linux/skbuff.h | 18 ++++++++++++++++++ + 1 file changed, 18 insertions(+) + +--- a/include/linux/skbuff.h ++++ b/include/linux/skbuff.h +@@ -1801,6 +1801,24 @@ static inline void pskb_trim_unique(stru + BUG_ON(err); + } + ++/* ++ * Caller wants to reduce memory needs before queueing skb ++ * The (expensive) copy should not be be done in fast path. ++ */ ++static inline struct sk_buff *skb_reduce_truesize(struct sk_buff *skb) ++{ ++ if (skb->truesize > 2 * SKB_TRUESIZE(skb->len)) { ++ struct sk_buff *nskb; ++ nskb = skb_copy_expand(skb, skb_headroom(skb), 0, ++ GFP_ATOMIC | __GFP_NOWARN); ++ if (nskb) { ++ __kfree_skb(skb); ++ skb = nskb; ++ } ++ } ++ return skb; ++} ++ + /** + * skb_orphan - orphan a buffer + * @skb: buffer to orphan diff --git a/target/linux/generic/patches-3.9/657-qdisc_reduce_truesize.patch b/target/linux/generic/patches-3.9/657-qdisc_reduce_truesize.patch new file mode 100644 index 0000000000..e27d0a04d6 --- /dev/null +++ b/target/linux/generic/patches-3.9/657-qdisc_reduce_truesize.patch @@ -0,0 +1,63 @@ +From bc9fec2f87d57bdbff30d296605e24504513f65c Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Dave=20T=C3=A4ht?= +Date: Mon, 17 Sep 2012 19:20:22 -0700 +Subject: [PATCH 4/7] net: add skb_reduce_truesize support to common qdiscs + +Reduce skb size under load when queues begin to fill on the +commont qdiscs. +--- + net/sched/sch_codel.c | 2 ++ + net/sched/sch_fifo.c | 12 ++++++++---- + net/sched/sch_fq_codel.c | 2 ++ + 3 files changed, 12 insertions(+), 4 deletions(-) + +--- a/net/sched/sch_codel.c ++++ b/net/sched/sch_codel.c +@@ -96,6 +96,8 @@ static int codel_qdisc_enqueue(struct sk + struct codel_sched_data *q; + + if (likely(qdisc_qlen(sch) < sch->limit)) { ++ if(qdisc_qlen(sch) > 128) ++ skb = skb_reduce_truesize(skb); + codel_set_enqueue_time(skb); + return qdisc_enqueue_tail(skb, sch); + } +--- a/net/sched/sch_fifo.c ++++ b/net/sched/sch_fifo.c +@@ -29,17 +29,21 @@ static int bfifo_enqueue(struct sk_buff + + static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) + { +- if (likely(skb_queue_len(&sch->q) < sch->limit)) ++ if (likely(skb_queue_len(&sch->q) < sch->limit)) { ++ if (skb_queue_len(&sch->q) > 128) ++ skb = skb_reduce_truesize(skb); + return qdisc_enqueue_tail(skb, sch); +- ++ } + return qdisc_reshape_fail(skb, sch); + } + + static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch) + { +- if (likely(skb_queue_len(&sch->q) < sch->limit)) ++ if (likely(skb_queue_len(&sch->q) < sch->limit)) { ++ if (skb_queue_len(&sch->q) > 128) ++ skb = skb_reduce_truesize(skb); + return qdisc_enqueue_tail(skb, sch); +- ++ } + /* queue full, remove one skb to fulfill the limit */ + __qdisc_queue_drop_head(sch, &sch->q); + sch->qstats.drops++; +--- a/net/sched/sch_fq_codel.c ++++ b/net/sched/sch_fq_codel.c +@@ -182,6 +182,8 @@ static int fq_codel_enqueue(struct sk_bu + return ret; + } + idx--; ++ if (sch->q.qlen > 128) ++ skb = skb_reduce_truesize(skb); + + codel_set_enqueue_time(skb); + flow = &q->flows[idx];