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net/sched: cake: avoid separate allocation of struct cake_sched_config

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Paolo pointed out that we can avoid separately allocating struct
cake_sched_config even in the non-mq case, by embedding it into struct
cake_sched_data. This reduces the complexity of the logic that swaps the
pointers and frees the old value, at the cost of adding 56 bytes to the
latter. Since cake_sched_data is already almost 17k bytes, this seems
like a reasonable tradeoff.

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Fixes: bc0ce2bad3 ("net/sched: sch_cake: Factor out config variables into separate struct")
Link: https://patch.msgid.link/20260113143157.2581680-1-toke@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Toke Høiland-Jørgensen
2026-01-13 15:31:56 +01:00
committed by Jakub Kicinski
parent 8fc8071041
commit 2a85541d95
1 changed files with 6 additions and 23 deletions
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29
net/sched/sch_cake.c
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@@ -221,6 +221,7 @@ struct cake_sched_data {
struct tcf_block *block;
struct cake_tin_data *tins;
struct cake_sched_config *config;
struct cake_sched_config initial_config;
struct cake_heap_entry overflow_heap[CAKE_QUEUES * CAKE_MAX_TINS];
@@ -2798,8 +2799,6 @@ static void cake_destroy(struct Qdisc *sch)
qdisc_watchdog_cancel(&q->watchdog);
tcf_block_put(q->block);
kvfree(q->tins);
if (q->config && !q->config->is_shared)
kvfree(q->config);
}
static void cake_config_init(struct cake_sched_config *q, bool is_shared)
@@ -2822,13 +2821,9 @@ static int cake_init(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
struct cake_sched_data *qd = qdisc_priv(sch);
struct cake_sched_config *q;
struct cake_sched_config *q = &qd->initial_config;
int i, j, err;
q = kzalloc(sizeof(*q), GFP_KERNEL);
if (!q)
return -ENOMEM;
cake_config_init(q, false);
sch->limit = 10240;
@@ -2842,14 +2837,13 @@ static int cake_init(struct Qdisc *sch, struct nlattr *opt,
if (opt) {
err = cake_change(sch, opt, extack);
if (err)
goto err;
return err;
}
err = tcf_block_get(&qd->block, &qd->filter_list, sch, extack);
if (err)
goto err;
return err;
quantum_div[0] = ~0;
for (i = 1; i <= CAKE_QUEUES; i++)
@@ -2857,10 +2851,8 @@ static int cake_init(struct Qdisc *sch, struct nlattr *opt,
qd->tins = kvcalloc(CAKE_MAX_TINS, sizeof(struct cake_tin_data),
GFP_KERNEL);
if (!qd->tins) {
err = -ENOMEM;
goto err;
}
if (!qd->tins)
return -ENOMEM;
for (i = 0; i < CAKE_MAX_TINS; i++) {
struct cake_tin_data *b = qd->tins + i;
@@ -2893,22 +2885,13 @@ static int cake_init(struct Qdisc *sch, struct nlattr *opt,
qd->last_checked_active = 0;
return 0;
err:
kvfree(qd->config);
qd->config = NULL;
return err;
}
static void cake_config_replace(struct Qdisc *sch, struct cake_sched_config *cfg)
{
struct cake_sched_data *qd = qdisc_priv(sch);
struct cake_sched_config *q = qd->config;
qd->config = cfg;
if (!q->is_shared)
kvfree(q);
cake_reconfigure(sch);
}