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-rw-r--r--fs/jbd/transaction.c38
1 files changed, 33 insertions, 5 deletions
diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
index 60d4c32c880..b51fbd4b291 100644
--- a/fs/jbd/transaction.c
+++ b/fs/jbd/transaction.c
@@ -25,6 +25,7 @@
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/highmem.h>
+#include <linux/hrtimer.h>
static void __journal_temp_unlink_buffer(struct journal_head *jh);
@@ -49,6 +50,7 @@ get_transaction(journal_t *journal, transaction_t *transaction)
{
transaction->t_journal = journal;
transaction->t_state = T_RUNNING;
+ transaction->t_start_time = ktime_get();
transaction->t_tid = journal->j_transaction_sequence++;
transaction->t_expires = jiffies + journal->j_commit_interval;
spin_lock_init(&transaction->t_handle_lock);
@@ -1370,7 +1372,7 @@ int journal_stop(handle_t *handle)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
- int old_handle_count, err;
+ int err;
pid_t pid;
J_ASSERT(journal_current_handle() == handle);
@@ -1399,6 +1401,17 @@ int journal_stop(handle_t *handle)
* on IO anyway. Speeds up many-threaded, many-dir operations
* by 30x or more...
*
+ * We try and optimize the sleep time against what the underlying disk
+ * can do, instead of having a static sleep time. This is usefull for
+ * the case where our storage is so fast that it is more optimal to go
+ * ahead and force a flush and wait for the transaction to be committed
+ * than it is to wait for an arbitrary amount of time for new writers to
+ * join the transaction. We acheive this by measuring how long it takes
+ * to commit a transaction, and compare it with how long this
+ * transaction has been running, and if run time < commit time then we
+ * sleep for the delta and commit. This greatly helps super fast disks
+ * that would see slowdowns as more threads started doing fsyncs.
+ *
* But don't do this if this process was the most recent one to
* perform a synchronous write. We do this to detect the case where a
* single process is doing a stream of sync writes. No point in waiting
@@ -1406,11 +1419,26 @@ int journal_stop(handle_t *handle)
*/
pid = current->pid;
if (handle->h_sync && journal->j_last_sync_writer != pid) {
+ u64 commit_time, trans_time;
+
journal->j_last_sync_writer = pid;
- do {
- old_handle_count = transaction->t_handle_count;
- schedule_timeout_uninterruptible(1);
- } while (old_handle_count != transaction->t_handle_count);
+
+ spin_lock(&journal->j_state_lock);
+ commit_time = journal->j_average_commit_time;
+ spin_unlock(&journal->j_state_lock);
+
+ trans_time = ktime_to_ns(ktime_sub(ktime_get(),
+ transaction->t_start_time));
+
+ commit_time = min_t(u64, commit_time,
+ 1000*jiffies_to_usecs(1));
+
+ if (trans_time < commit_time) {
+ ktime_t expires = ktime_add_ns(ktime_get(),
+ commit_time);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
+ }
}
current->journal_info = NULL;