All of lore.kernel.org
 help / color / mirror / Atom feed
From: Liu Bo <bo.liu@linux.alibaba.com>
To: <linux-btrfs@vger.kernel.org>
Subject: [PATCH v2] Btrfs: skip set_page_dirty if eb is dirty
Date: Fri, 14 Sep 2018 01:44:42 +0800	[thread overview]
Message-ID: <1536860682-41012-1-git-send-email-bo.liu@linux.alibaba.com> (raw)
In-Reply-To: <1536703587-94565-1-git-send-email-bo.liu@linux.alibaba.com>

As long as @eb is marked with EXTENT_BUFFER_DIRTY, all of its pages
are dirty, so no need to set pages dirty again.

Ftrace showed that the loop took 10us on my dev box, so removing this
can save us at least 10us if eb is already dirty.

Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
---
v2: Update the patch's description.

 fs/btrfs/extent_io.c | 11 +++++++----
 fs/btrfs/extent_io.h |  2 +-
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 628f1aef34b0..fb2bf50134a1 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -5165,11 +5165,11 @@ void clear_extent_buffer_dirty(struct extent_buffer *eb)
 	WARN_ON(atomic_read(&eb->refs) == 0);
 }
 
-int set_extent_buffer_dirty(struct extent_buffer *eb)
+bool set_extent_buffer_dirty(struct extent_buffer *eb)
 {
 	int i;
 	int num_pages;
-	int was_dirty = 0;
+	bool was_dirty;
 
 	check_buffer_tree_ref(eb);
 
@@ -5179,8 +5179,11 @@ int set_extent_buffer_dirty(struct extent_buffer *eb)
 	WARN_ON(atomic_read(&eb->refs) == 0);
 	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
 
-	for (i = 0; i < num_pages; i++)
-		set_page_dirty(eb->pages[i]);
+	if (!was_dirty) {
+		for (i = 0; i < num_pages; i++)
+			set_page_dirty(eb->pages[i]);
+	}
+
 	return was_dirty;
 }
 
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index b4d03e677e1d..f2ab42d57f02 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -479,7 +479,7 @@ void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
 void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
 				unsigned long pos, unsigned long len);
 void clear_extent_buffer_dirty(struct extent_buffer *eb);
-int set_extent_buffer_dirty(struct extent_buffer *eb);
+bool set_extent_buffer_dirty(struct extent_buffer *eb);
 void set_extent_buffer_uptodate(struct extent_buffer *eb);
 void clear_extent_buffer_uptodate(struct extent_buffer *eb);
 int extent_buffer_under_io(struct extent_buffer *eb);
-- 
1.8.3.1

  parent reply	other threads:[~2018-09-13 22:55 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-11 22:06 [PATCH] Btrfs: skip set_page_dirty if eb is dirty Liu Bo
2018-09-12  6:37 ` Nikolay Borisov
2018-09-12 19:27   ` Liu Bo
2018-09-13 11:29     ` David Sterba
2018-09-13 16:54       ` Liu Bo
2018-09-13 17:44 ` Liu Bo [this message]
2018-09-14  6:30   ` [PATCH v2] " Nikolay Borisov
2018-09-14 12:59   ` David Sterba

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1536860682-41012-1-git-send-email-bo.liu@linux.alibaba.com \
    --to=bo.liu@linux.alibaba.com \
    --cc=linux-btrfs@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.