On Sun, Sep 28, 2014 at 05:25:37PM -0700, Eric Wheeler wrote: > Hello Kent, Ross, all: > > We're getting bcache_gc backtraces and soft lockups; the system continues to > be responsive and eventually recovers. We are running 3.17-rc6. (This > appears to be a continuation of the thread from 2014-09-15) > > Please see the following two backtraces. The first shows up in > btree_gc_count_keys(), the other is triggered somehow by rcu_sched. We will > test with -rc7 this week, though I didn't see any bcache commits in rc7. > > The server is quite busy: > dd in userspace from dm-thinp snapshots to another server > two DRBD verify's active backed by dm-thinp volumes > note that, dd fills up the buffers so this could be operating with few > pages free. (Though we have min-mem set to 256MB.) > > I see we are hitting functions like bch_ptr_bad() and bch_extent_bad(). > Could that indicate a cache corruption on our volume?
No - those are the normal "check the validity of medata" functions. > I'm happy to test patches if you have any suggestions or tests that I should > run it through. I think it might just be a missing cond_resched()... there's a check during garbage collection for need_resched() but it appears we might not actually be calling schedule() then. Try this patch: commit a64afc92e17e709bdd1618edd04bc608f6a44c55 Author: Kent Overstreet <[email protected]> Date: Sat Nov 1 13:44:13 2014 -0700 bcache: Add a cond_resched() call to gc Change-Id: Id4f18c533b80ddb40df94ed0bb5e2a236a4bc325 diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 00cde40db5..218f21ac02 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -1741,6 +1741,7 @@ static void bch_btree_gc(struct cache_set *c) do { ret = btree_root(gc_root, c, &op, &writes, &stats); closure_sync(&writes); + cond_resched(); if (ret && ret != -EAGAIN) pr_warn("gc failed!"); -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
