From: Denis Lunev Date: Sun, 31 Jul 2005 00:47:25 +0000 (-0700) Subject: [NET] Fix too aggressive backoff in dst garbage collection X-Git-Tag: v2.6.13-rc5~43 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f0098f7863f814a5adc0b9cb271605d063cad7fa;p=linux-2.6 [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 --- diff --git a/net/core/dst.c b/net/core/dst.c index fc434ade52..334790da9f 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",