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-rw-r--r--fs/jbd/transaction.c10
-rw-r--r--include/linux/jbd.h4
2 files changed, 13 insertions, 1 deletions
diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
index 429f4b2..ca91797 100644
--- a/fs/jbd/transaction.c
+++ b/fs/jbd/transaction.c
@@ -1308,6 +1308,7 @@ int journal_stop(handle_t *handle)
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
int old_handle_count, err;
+ pid_t pid;
J_ASSERT(transaction->t_updates > 0);
J_ASSERT(journal_current_handle() == handle);
@@ -1333,8 +1334,15 @@ int journal_stop(handle_t *handle)
* It doesn't cost much - we're about to run a commit and sleep
* on IO anyway. Speeds up many-threaded, many-dir operations
* by 30x or more...
+ *
+ * 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
+ * for joiners in that case.
*/
- if (handle->h_sync) {
+ pid = current->pid;
+ if (handle->h_sync && journal->j_last_sync_writer != pid) {
+ journal->j_last_sync_writer = pid;
do {
old_handle_count = transaction->t_handle_count;
schedule_timeout_uninterruptible(1);
diff --git a/include/linux/jbd.h b/include/linux/jbd.h
index 558cb4c..751bb38 100644
--- a/include/linux/jbd.h
+++ b/include/linux/jbd.h
@@ -23,6 +23,7 @@
#define jfs_debug jbd_debug
#else
+#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/journal-head.h>
#include <linux/stddef.h>
@@ -618,6 +619,7 @@ struct transaction_s
* @j_wbuf: array of buffer_heads for journal_commit_transaction
* @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
* number that will fit in j_blocksize
+ * @j_last_sync_writer: most recent pid which did a synchronous write
* @j_private: An opaque pointer to fs-private information.
*/
@@ -807,6 +809,8 @@ struct journal_s
struct buffer_head **j_wbuf;
int j_wbufsize;
+ pid_t j_last_sync_writer;
+
/*
* An opaque pointer to fs-private information. ext3 puts its
* superblock pointer here
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