From 0274899903d560bccaca7db3f052d923b4466c96 Mon Sep 17 00:00:00 2001 From: Coly Li Date: Thu, 13 Feb 2020 22:12:06 +0800 Subject: [PATCH] bcache: Revert "bcache: shrink btree node cache after bch_btree_check()" This reverts commit 1683ab0ede4d0646fb1e09edf3d9a8b6333749e4. In my testing, sometimes even all the cached btree nodes are freed, creating gc and allocator kernel threads may still fail. Finally it turns out that kthread_run() may fail if there is pending signal for current task. And the pending signal is sent from OOM killer which is triggered by memory consuption in bch_btree_check(). Therefore explicitly shrinking bcache btree node here does not help, and after the shrinker callback is improved, as well as pending signals are ignored before creating kernel threads, now such operation is unncessary anymore. This patch reverts the commit 1683ab0ede4d ("bcache: shrink btree node cache after bch_btree_check()") because we have better improvement now. Signed-off-by: Coly Li Signed-off-by: Jens Axboe --- drivers/md/bcache/super.c | 17 ----------------- 1 file changed, 17 deletions(-) diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 2749daf097242..0c3c5419c52b6 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1917,23 +1917,6 @@ static int run_cache_set(struct cache_set *c) if (bch_btree_check(c)) goto err; - /* - * bch_btree_check() may occupy too much system memory which - * has negative effects to user space application (e.g. data - * base) performance. Shrink the mca cache memory proactively - * here to avoid competing memory with user space workloads.. - */ - if (!c->shrinker_disabled) { - struct shrink_control sc; - - sc.gfp_mask = GFP_KERNEL; - sc.nr_to_scan = c->btree_cache_used * c->btree_pages; - /* first run to clear b->accessed tag */ - c->shrink.scan_objects(&c->shrink, &sc); - /* second run to reap non-accessed nodes */ - c->shrink.scan_objects(&c->shrink, &sc); - } - bch_journal_mark(c, &journal); bch_initial_gc_finish(c); pr_debug("btree_check() done"); -- 2.39.5