From c2e8dcf7fa43ed236cb341c33aa3a75687557c43 Mon Sep 17 00:00:00 2001 From: Coly Li Date: Thu, 9 Aug 2018 15:48:44 +0800 Subject: [PATCH] bcache: avoid unncessary cache prefetch bch_btree_node_get() In bch_btree_node_get() the read-in btree node will be partially prefetched into L1 cache for following bset iteration (if there is). But if the btree node read is failed, the perfetch operations will waste L1 cache space. This patch checkes whether read operation and only does cache prefetch when read I/O succeeded. Signed-off-by: Coly Li Signed-off-by: Jens Axboe --- drivers/md/bcache/btree.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 475008fbbaab..c19f7716df88 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -1011,6 +1011,13 @@ retry: BUG_ON(b->level != level); } + if (btree_node_io_error(b)) { + rw_unlock(write, b); + return ERR_PTR(-EIO); + } + + BUG_ON(!b->written); + b->parent = parent; b->accessed = 1; @@ -1022,13 +1029,6 @@ retry: for (; i <= b->keys.nsets; i++) prefetch(b->keys.set[i].data); - if (btree_node_io_error(b)) { - rw_unlock(write, b); - return ERR_PTR(-EIO); - } - - BUG_ON(!b->written); - return b; } -- 2.30.2