Commit bfe2b014 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm stats: add cond_resched when looping over entries 



dm-stats can be used with a very large number of entries (it is only
limited by 1/4 of total system memory), so add rescheduling points to
the loops that iterate over the entries.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 4edadf6d

drivers/md/dm-stats.c

+8 −0
Original line number Diff line number Diff line
@@ -225,6 +225,7 @@ void dm_stats_cleanup(struct dm_stats *stats) 
				       atomic_read(&shared->in_flight[READ]),

				       atomic_read(&shared->in_flight[WRITE]));

			}

			cond_resched();

		}

		dm_stat_free(&s->rcu_head);

	}
@@ -330,6 +331,7 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, 
	for (ni = 0; ni < n_entries; ni++) {

		atomic_set(&s->stat_shared[ni].in_flight[READ], 0);

		atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);

		cond_resched();

	}



	if (s->n_histogram_entries) {
@@ -342,6 +344,7 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, 
		for (ni = 0; ni < n_entries; ni++) {

			s->stat_shared[ni].tmp.histogram = hi;

			hi += s->n_histogram_entries + 1;

			cond_resched();

		}

	}
@@ -362,6 +365,7 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, 
			for (ni = 0; ni < n_entries; ni++) {

				p[ni].histogram = hi;

				hi += s->n_histogram_entries + 1;

				cond_resched();

			}

		}

	}
@@ -500,6 +504,7 @@ static int dm_stats_list(struct dm_stats *stats, const char *program, 
			}

			DMEMIT("\n");

		}

		cond_resched();

	}

	mutex_unlock(&stats->mutex);
@@ -777,6 +782,7 @@ static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end, 
				local_irq_enable();

			}

		}

		cond_resched();

	}

}
@@ -892,6 +898,8 @@ static int dm_stats_print(struct dm_stats *stats, int id, 


		if (unlikely(sz + 1 >= maxlen))

			goto buffer_overflow;



		cond_resched();

	}



	if (clear)