From f0098f7863f814a5adc0b9cb271605d063cad7fa Mon Sep 17 00:00:00 2001 From: Denis Lunev Date: Sat, 30 Jul 2005 17:47:25 -0700 Subject: [PATCH] [NET] Fix too aggressive backoff in dst garbage collection The bug is evident when it is seen once. dst gc timer was backed off, when gc queue is not empty. But this means that timer quickly backs off, if at least one destination remains in use. Normally, the bug is invisible, because adding new dst entry to queue cancels the backoff. But it shots deadly with destination cache overflow when new destinations are not released for long time f.e. after an interface goes down. The fix is to cancel backoff when something was released. Signed-off-by: Denis Lunev Signed-off-by: Alexey Kuznetsov Signed-off-by: David S. Miller --- net/core/dst.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/net/core/dst.c b/net/core/dst.c index fc434ade5270..334790da9f16 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -45,6 +45,7 @@ static struct timer_list dst_gc_timer = static void dst_run_gc(unsigned long dummy) { int delayed = 0; + int work_performed; struct dst_entry * dst, **dstp; if (!spin_trylock(&dst_lock)) { @@ -52,9 +53,9 @@ static void dst_run_gc(unsigned long dummy) return; } - del_timer(&dst_gc_timer); dstp = &dst_garbage_list; + work_performed = 0; while ((dst = *dstp) != NULL) { if (atomic_read(&dst->__refcnt)) { dstp = &dst->next; @@ -62,6 +63,7 @@ static void dst_run_gc(unsigned long dummy) continue; } *dstp = dst->next; + work_performed = 1; dst = dst_destroy(dst); if (dst) { @@ -86,9 +88,14 @@ static void dst_run_gc(unsigned long dummy) dst_gc_timer_inc = DST_GC_MAX; goto out; } - if ((dst_gc_timer_expires += dst_gc_timer_inc) > DST_GC_MAX) - dst_gc_timer_expires = DST_GC_MAX; - dst_gc_timer_inc += DST_GC_INC; + if (!work_performed) { + if ((dst_gc_timer_expires += dst_gc_timer_inc) > DST_GC_MAX) + dst_gc_timer_expires = DST_GC_MAX; + dst_gc_timer_inc += DST_GC_INC; + } else { + dst_gc_timer_inc = DST_GC_INC; + dst_gc_timer_expires = DST_GC_MIN; + } dst_gc_timer.expires = jiffies + dst_gc_timer_expires; #if RT_CACHE_DEBUG >= 2 printk("dst_total: %d/%d %ld\n", -- 2.20.1