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| author | Steffen Klassert <steffen.klassert@secunet.com> | 2016-02-22 10:40:07 +0100 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2016-03-17 10:28:42 +0100 |
| commit | 6ad3122a08e3a9c2148873665752e87cf4f393cc (patch) | |
| tree | 95c89c906cbdf02f28c71bbfdc0513dfe1cdddae | |
| parent | qmi_wwan: add "4G LTE usb-modem U901" (diff) | |
| download | linux-6ad3122a08e3a9c2148873665752e87cf4f393cc.tar.xz linux-6ad3122a08e3a9c2148873665752e87cf4f393cc.zip | |
flowcache: Avoid OOM condition under preasure
We can hit an OOM condition if we are under presure because
we can not free the entries in gc_list fast enough. So add
a counter for the not yet freed entries in the gc_list and
refuse new allocations if the value is too high.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
| -rw-r--r-- | include/net/netns/xfrm.h | 1 | ||||
| -rw-r--r-- | net/core/flow.c | 14 |
2 files changed, 14 insertions, 1 deletions
diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h index 730d82ad6ee5..24cd3949a9a4 100644 --- a/include/net/netns/xfrm.h +++ b/include/net/netns/xfrm.h @@ -80,6 +80,7 @@ struct netns_xfrm { struct flow_cache flow_cache_global; atomic_t flow_cache_genid; struct list_head flow_cache_gc_list; + atomic_t flow_cache_gc_count; spinlock_t flow_cache_gc_lock; struct work_struct flow_cache_gc_work; struct work_struct flow_cache_flush_work; diff --git a/net/core/flow.c b/net/core/flow.c index 1033725be40b..3937b1b68d5b 100644 --- a/net/core/flow.c +++ b/net/core/flow.c @@ -92,8 +92,11 @@ static void flow_cache_gc_task(struct work_struct *work) list_splice_tail_init(&xfrm->flow_cache_gc_list, &gc_list); spin_unlock_bh(&xfrm->flow_cache_gc_lock); - list_for_each_entry_safe(fce, n, &gc_list, u.gc_list) + list_for_each_entry_safe(fce, n, &gc_list, u.gc_list) { flow_entry_kill(fce, xfrm); + atomic_dec(&xfrm->flow_cache_gc_count); + WARN_ON(atomic_read(&xfrm->flow_cache_gc_count) < 0); + } } static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp, @@ -101,6 +104,7 @@ static void flow_cache_queue_garbage(struct flow_cache_percpu *fcp, struct netns_xfrm *xfrm) { if (deleted) { + atomic_add(deleted, &xfrm->flow_cache_gc_count); fcp->hash_count -= deleted; spin_lock_bh(&xfrm->flow_cache_gc_lock); list_splice_tail(gc_list, &xfrm->flow_cache_gc_list); @@ -232,6 +236,13 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir, if (fcp->hash_count > fc->high_watermark) flow_cache_shrink(fc, fcp); + if (fcp->hash_count > 2 * fc->high_watermark || + atomic_read(&net->xfrm.flow_cache_gc_count) > fc->high_watermark) { + atomic_inc(&net->xfrm.flow_cache_genid); + flo = ERR_PTR(-ENOBUFS); + goto ret_object; + } + fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC); if (fle) { fle->net = net; @@ -446,6 +457,7 @@ int flow_cache_init(struct net *net) INIT_WORK(&net->xfrm.flow_cache_gc_work, flow_cache_gc_task); INIT_WORK(&net->xfrm.flow_cache_flush_work, flow_cache_flush_task); mutex_init(&net->xfrm.flow_flush_sem); + atomic_set(&net->xfrm.flow_cache_gc_count, 0); fc->hash_shift = 10; fc->low_watermark = 2 * flow_cache_hash_size(fc); |