From: Theodore Tso <tytso@mit.edu>
To: Jens Axboe <jens.axboe@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Developers List <linux-kernel@vger.kernel.org>,
Ext4 Developers List <linux-ext4@vger.kernel.org>,
jack@suse.cz
Subject: Re: [PATCH 1/3] block_write_full_page: Use synchronous writes for WBC_SYNC_ALL writebacks
Date: Tue, 7 Apr 2009 15:09:13 -0400 [thread overview]
Message-ID: <20090407190913.GA31723@mit.edu> (raw)
In-Reply-To: <20090407075732.GO5178@kernel.dk>
On Tue, Apr 07, 2009 at 09:57:32AM +0200, Jens Axboe wrote:
> > > It looks like a good candidate for WRITE_SYNC_PLUG instead,
> >
So is this patch sane? (Compile-tested only, since I'm at a
conference at the moment). Am I using the proper abstraction to
unplug the block device? If not, it might be nice to document the
preferred for callers into the block layer.
(BTW, I was looking at Documentation/biodoc.txt, and I found some
clearly old documentation bits: "This is just the same as in 2.4 so
far, though per-device unplugging support is anticipated for 2.5." :-)
- Ted
[RFQ] Smart unplugging for page writeback
Now that we have a distinction between WRITE_SYNC and WRITE_SYNC_PLUG,
use WRITE_SYNC_PLUG in block_write_full_page(), and then before we
wait for page writebacks to complete in jbd, jbd2, and filemap, call
blk_unplug() to make sure the writes are on the way to the disk.
diff --git a/fs/buffer.c b/fs/buffer.c
index 977e12a..95b5390 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1646,7 +1646,8 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
struct buffer_head *bh, *head;
const unsigned blocksize = 1 << inode->i_blkbits;
int nr_underway = 0;
- int write_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
+ int write_op = (wbc->sync_mode == WB_SYNC_ALL ?
+ WRITE_SYNC_PLUG : WRITE);
BUG_ON(!PageLocked(page));
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index a8e8513..3e6726f 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -21,6 +21,7 @@
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/bio.h>
+#include <linux/blkdev.h>
/*
* Default IO end handler for temporary BJ_IO buffer_heads.
@@ -196,6 +197,7 @@ static int journal_submit_data_buffers(journal_t *journal,
int locked;
int bufs = 0;
struct buffer_head **wbuf = journal->j_wbuf;
+ struct block_device *fs_bdev = 0;
int err = 0;
/*
@@ -213,6 +215,7 @@ write_out_data:
while (commit_transaction->t_sync_datalist) {
jh = commit_transaction->t_sync_datalist;
bh = jh2bh(jh);
+ fs_bdev = bh->b_bdev;
locked = 0;
/* Get reference just to make sure buffer does not disappear
@@ -290,6 +293,8 @@ write_out_data:
}
spin_unlock(&journal->j_list_lock);
journal_do_submit_data(wbuf, bufs, write_op);
+ if (fs_bdev)
+ blk_unplug(bdev_get_queue(fs_bdev));
return err;
}
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 282750c..b5448dd 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -26,6 +26,7 @@
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/bio.h>
+#include <linux/blkdev.h>
/*
* Default IO end handler for temporary BJ_IO buffer_heads.
@@ -176,6 +177,7 @@ static int journal_wait_on_commit_record(journal_t *journal,
retry:
clear_buffer_dirty(bh);
+ blk_unplug(bdev_get_queue(bh->b_bdev));
wait_on_buffer(bh);
if (buffer_eopnotsupp(bh) && (journal->j_flags & JBD2_BARRIER)) {
printk(KERN_WARNING
@@ -241,10 +243,12 @@ static int journal_submit_data_buffers(journal_t *journal,
struct jbd2_inode *jinode;
int err, ret = 0;
struct address_space *mapping;
+ struct block_device *fs_bdev = 0;
spin_lock(&journal->j_list_lock);
list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
mapping = jinode->i_vfs_inode->i_mapping;
+ fs_bdev = jinode->i_vfs_inode->i_sb->s_bdev;
jinode->i_flags |= JI_COMMIT_RUNNING;
spin_unlock(&journal->j_list_lock);
/*
@@ -262,6 +266,8 @@ static int journal_submit_data_buffers(journal_t *journal,
wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
}
spin_unlock(&journal->j_list_lock);
+ if (fs_bdev)
+ blk_unplug(bdev_get_queue(fs_bdev));
return ret;
}
diff --git a/mm/filemap.c b/mm/filemap.c
index 2e2d38e..eff2ed9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -274,6 +274,10 @@ int wait_on_page_writeback_range(struct address_space *mapping,
if (end < start)
return 0;
+ if (mapping->host && mapping->host->i_sb && mapping->host->i_sb &&
+ mapping->host->i_sb->s_bdev)
+ blk_unplug(bdev_get_queue(mapping->host->i_sb->s_bdev));
+
pagevec_init(&pvec, 0);
index = start;
while ((index <= end) &&
next prev parent reply other threads:[~2009-04-07 19:09 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-27 20:24 [PATCH 0/3] Ext3 latency improvement patches Theodore Ts'o
2009-03-27 20:24 ` [PATCH 1/3] block_write_full_page: Use synchronous writes for WBC_SYNC_ALL writebacks Theodore Ts'o
2009-03-27 20:24 ` [PATCH 2/3] ext3: Use WRITE_SYNC for commits which are caused by fsync() Theodore Ts'o
2009-03-27 20:24 ` [PATCH 3/3] ext3: Avoid starting a transaction in writepage when not necessary Theodore Ts'o
2009-03-27 22:23 ` Jan Kara
2009-03-27 23:03 ` Theodore Tso
2009-03-30 13:22 ` Jan Kara
2009-03-27 22:20 ` [PATCH 2/3] ext3: Use WRITE_SYNC for commits which are caused by fsync() Jan Kara
2009-03-27 20:55 ` [PATCH 1/3] block_write_full_page: Use synchronous writes for WBC_SYNC_ALL writebacks Jan Kara
2009-04-07 6:21 ` Andrew Morton
2009-04-07 6:50 ` Andrew Morton
2009-04-07 7:08 ` Jens Axboe
2009-04-07 7:17 ` Jens Axboe
2009-04-07 8:16 ` Jens Axboe
2009-04-07 7:23 ` Andrew Morton
2009-04-07 7:57 ` Jens Axboe
2009-04-07 19:09 ` Theodore Tso [this message]
2009-04-07 19:32 ` Jens Axboe
2009-04-07 21:44 ` Theodore Tso
2009-04-07 22:19 ` [PATCH] block_write_full_page: switch synchronous writes to use WRITE_SYNC_PLUG Theodore Tso
2009-04-07 23:09 ` Andrew Morton
2009-04-07 23:46 ` Theodore Tso
2009-04-08 8:08 ` Jens Axboe
2009-04-08 22:34 ` Andrew Morton
2009-04-09 17:59 ` Jens Axboe
2009-04-08 6:00 ` Jens Axboe
2009-04-08 15:26 ` Theodore Tso
2009-04-08 5:58 ` [PATCH 1/3] block_write_full_page: Use synchronous writes for WBC_SYNC_ALL writebacks Jens Axboe
2009-04-08 15:25 ` Theodore Tso
2009-04-07 14:19 ` Theodore Tso
2009-03-27 20:50 ` [PATCH 0/3] Ext3 latency improvement patches Chris Mason
2009-03-27 21:03 ` Chris Mason
2009-03-27 21:19 ` Jan Kara
2009-03-27 21:30 ` Theodore Tso
2009-03-27 21:54 ` Jan Kara
2009-03-27 23:09 ` Theodore Tso
2009-03-28 0:14 ` Jeff Garzik
2009-03-28 0:24 ` David Rees
2009-03-30 14:16 ` Ric Wheeler
2009-03-30 11:23 ` Aneesh Kumar K.V
2009-03-30 11:44 ` Chris Mason
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