md/r5cache: run_no_space_stripes() when R5C_LOG_CRITICAL == 0

With writeback cache, we define log space critical as

   free_space < 2 * reclaim_required_space

So the deassert of R5C_LOG_CRITICAL could happen when
  1. free_space increases
  2. reclaim_required_space decreases

Currently, run_no_space_stripes() is called when 1 happens, but
not (always) when 2 happens.

With this patch, run_no_space_stripes() is call when
R5C_LOG_CRITICAL is cleared.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index e786d4e555cc3fa404394d16a57d608d522a664a..c36f86b47252bfc1a048105095fb1046864035cf 100644 (file)
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -370,6 +370,7 @@ static inline void r5c_update_log_state(struct r5l_log *log)
        struct r5conf *conf = log->rdev->mddev->private;
        sector_t free_space;
        sector_t reclaim_space;
+       bool wake_reclaim = false;
 
        if (!r5c_is_writeback(log))
                return;
@@ -379,12 +380,18 @@ static inline void r5c_update_log_state(struct r5l_log *log)
        reclaim_space = r5c_log_required_to_flush_cache(conf);
        if (free_space < 2 * reclaim_space)
                set_bit(R5C_LOG_CRITICAL, &conf->cache_state);
-       else
+       else {
+               if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state))
+                       wake_reclaim = true;
                clear_bit(R5C_LOG_CRITICAL, &conf->cache_state);
+       }
        if (free_space < 3 * reclaim_space)
                set_bit(R5C_LOG_TIGHT, &conf->cache_state);
        else
                clear_bit(R5C_LOG_TIGHT, &conf->cache_state);
+
+       if (wake_reclaim)
+               r5l_wake_reclaim(log, 0);
 }
 
 /*
@@ -1345,6 +1352,10 @@ static void r5c_do_reclaim(struct r5conf *conf)
                spin_unlock(&conf->device_lock);
                spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
        }
+
+       if (!test_bit(R5C_LOG_CRITICAL, &conf->cache_state))
+               r5l_run_no_space_stripes(log);
+
        md_wakeup_thread(conf->mddev->thread);
 }
 
@@ -2401,6 +2412,7 @@ void r5c_finish_stripe_write_out(struct r5conf *conf,
        spin_unlock_irq(&conf->log->stripe_in_journal_lock);
        sh->log_start = MaxSector;
        atomic_dec(&conf->log->stripe_in_journal_count);
+       r5c_update_log_state(conf->log);
 }
 
 int