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inet: frag: remove periodic secret rebuild timer

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merge functionality into the eviction workqueue.

Instead of rebuilding every n seconds, take advantage of the upper
hash chain length limit.

If we hit it, mark table for rebuild and schedule workqueue.
To prevent frequent rebuilds when we're completely overloaded,
don't rebuild more than once every 5 seconds.

ipfrag_secret_interval sysctl is now obsolete and has been marked as
deprecated, it still can be changed so scripts won't be broken but it
won't have any effect. A comment is left above each unused secret_timer
variable to avoid confusion.

Joint work with Nikolay Aleksandrov.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Westphal 2014-07-24 16:50:35 +02:00 • committed by David S. Miller
parent 3fd588eb90
commit e3a57d18b0
7 changed files with 40 additions and 33 deletions
Download patch file Download diff file Expand all files Collapse all files

43
net/ipv4/inet_fragment.c
View file

@ -28,6 +28,9 @@
#define INETFRAGS_EVICT_BUCKETS 128
#define INETFRAGS_EVICT_MAX 512
/* don't rebuild inetfrag table with new secret more often than this */
#define INETFRAGS_MIN_REBUILD_INTERVAL (5 * HZ)
/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
* Value : 0xff if frame should be dropped.
* 0 or INET_ECN_CE value, to be ORed in to final iph->tos field
@ -55,16 +58,24 @@ inet_frag_hashfn(const struct inet_frags *f, const struct inet_frag_queue *q)
return f->hashfn(q) & (INETFRAGS_HASHSZ - 1);
}
static void inet_frag_secret_rebuild(unsigned long dummy)
static bool inet_frag_may_rebuild(struct inet_frags *f)
{
return time_after(jiffies,
f->last_rebuild_jiffies + INETFRAGS_MIN_REBUILD_INTERVAL);
}
static void inet_frag_secret_rebuild(struct inet_frags *f)
{
struct inet_frags *f = (struct inet_frags *)dummy;
unsigned long now = jiffies;
int i;
/* Per bucket lock NOT needed here, due to write lock protection */
write_lock(&f->lock);
write_lock_bh(&f->lock);
if (!inet_frag_may_rebuild(f))
goto out;
get_random_bytes(&f->rnd, sizeof(u32));
for (i = 0; i < INETFRAGS_HASHSZ; i++) {
struct inet_frag_bucket *hb;
struct inet_frag_queue *q;
@ -85,9 +96,11 @@ static void inet_frag_secret_rebuild(unsigned long dummy)
}
}
}
write_unlock(&f->lock);
mod_timer(&f->secret_timer, now + f->secret_interval);
f->rebuild = false;
f->last_rebuild_jiffies = jiffies;
out:
write_unlock_bh(&f->lock);
}
static bool inet_fragq_should_evict(const struct inet_frag_queue *q)
@ -162,6 +175,8 @@ static void inet_frag_worker(struct work_struct *work)
f->next_bucket = i;
read_unlock_bh(&f->lock);
if (f->rebuild && inet_frag_may_rebuild(f))
inet_frag_secret_rebuild(f);
}
static void inet_frag_schedule_worker(struct inet_frags *f)
@ -183,11 +198,7 @@ void inet_frags_init(struct inet_frags *f)
INIT_HLIST_HEAD(&hb->chain);
}
rwlock_init(&f->lock);
setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
(unsigned long)f);
f->secret_timer.expires = jiffies + f->secret_interval;
add_timer(&f->secret_timer);
f->last_rebuild_jiffies = 0;
}
EXPORT_SYMBOL(inet_frags_init);
@ -199,7 +210,6 @@ EXPORT_SYMBOL(inet_frags_init_net);
void inet_frags_fini(struct inet_frags *f)
{
del_timer(&f->secret_timer);
cancel_work_sync(&f->frags_work);
}
EXPORT_SYMBOL(inet_frags_fini);
@ -399,8 +409,13 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
if (depth <= INETFRAGS_MAXDEPTH)
return inet_frag_create(nf, f, key);
else
return ERR_PTR(-ENOBUFS);
if (inet_frag_may_rebuild(f)) {
f->rebuild = true;
inet_frag_schedule_worker(f);
}
return ERR_PTR(-ENOBUFS);
}
EXPORT_SYMBOL(inet_frag_find);