lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [day] [month] [year] [list]
Message-Id: <1298916783-31621-1-git-send-email-tytso@mit.edu>
Date:	Mon, 28 Feb 2011 13:13:03 -0500
From:	Theodore Ts'o <tytso@....edu>
To:	Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:	Theodore Ts'o <tytso@....edu>
Subject: [PATCH] ext4: optimize ext4_bio_write_page() when no extent conversion is needed

If no extent conversion is required, wake up any processes waiting for
the page's writeback to be complete and free the ext4_io_end structure
directly in ext4_end_bio() instead of dropping it on the linked list
(which requires taking a spinlock to queue and dequeue the io_end
structure), and waiting for the workqueue to do this work.

This removes an extra scheduling delay before process waiting for an
fsync() to complete gets woken up, and it also reduces the CPU
overhead for a random write workload.

Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
 fs/ext4/page-io.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index d5c391f..0cfd03e 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -259,6 +259,11 @@ static void ext4_end_bio(struct bio *bio, int error)
 			     bi_sector >> (inode->i_blkbits - 9));
 	}
 
+	if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
+		ext4_free_io_end(io_end);
+		return;
+	}
+
 	/* Add the io_end to per-inode completed io list*/
 	spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
 	list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
-- 
1.7.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ