xfs
[Top] [All Lists]

[PATCH 09/11] xfs: reduce ioend latency

To: xfs@xxxxxxxxxxx
Subject: [PATCH 09/11] xfs: reduce ioend latency
From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Date: Tue, 23 Aug 2011 04:28:11 -0400
References: <20110823082802.335389799@xxxxxxxxxxxxxxxxxxxxxx>
User-agent: quilt/0.48-1
There is no reason to queue up ioends for processing in user context
unless we actually need it.  Just complete ioends that do not convert
unwritten extents or need a size update from the end_io context.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>

Index: xfs/fs/xfs/xfs_aops.c
===================================================================
--- xfs.orig/fs/xfs/xfs_aops.c  2011-08-13 10:57:57.559366326 -0700
+++ xfs/fs/xfs/xfs_aops.c       2011-08-13 10:57:57.979364052 -0700
@@ -150,6 +150,15 @@ xfs_ioend_new_eof(
 }
 
 /*
+ * Fast and loose check if this write could update the on-disk inode size.
+ */
+static inline bool xfs_ioend_is_append(struct xfs_ioend *ioend)
+{
+       return ioend->io_offset + ioend->io_size >
+               XFS_I(ioend->io_inode)->i_d.di_size;
+}
+
+/*
  * Update on-disk file size now that data has been written to disk.  The
  * current in-memory file size is i_size.  If a write is beyond eof i_new_size
  * will be the intended file size until i_size is updated.  If this write does
@@ -186,6 +195,9 @@ xfs_setfilesize(
 
 /*
  * Schedule IO completion handling on the final put of an ioend.
+ *
+ * If there is no work to do we might as well call it a day and free the
+ * ioend right now.
  */
 STATIC void
 xfs_finish_ioend(
@@ -194,8 +206,10 @@ xfs_finish_ioend(
        if (atomic_dec_and_test(&ioend->io_remaining)) {
                if (ioend->io_type == IO_UNWRITTEN)
                        queue_work(xfsconvertd_workqueue, &ioend->io_work);
-               else
+               else if (xfs_ioend_is_append(ioend))
                        queue_work(xfsdatad_workqueue, &ioend->io_work);
+               else
+                       xfs_destroy_ioend(ioend);
        }
 }
 

<Prev in Thread] Current Thread [Next in Thread>