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: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-id: <000001d0ec5d$0bbd1880$23374980$@samsung.com>
Date:	Fri, 11 Sep 2015 14:41:53 +0800
From:	Chao Yu <chao2.yu@...sung.com>
To:	Jaegeuk Kim <jaegeuk@...nel.org>
Cc:	linux-f2fs-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org
Subject: [PATCH 5/7] f2fs: enhance multithread dio write performance

When dio writes perform concurrently, our performace will be low because of
Thread A's allocation of multi continuous blocks will be break by Thread B,
there are two cases as below:
 - In Thread B, we may change current segment to a new segment for LFS
   allocation if we dio write in the beginning of the file.
 - In Thread B, we may allocate blocks in the middle of Thread A's
   allocation, which make blocks which allocated in Thread A being
   discontinuous.

This patch adds writepages mutex lock to make block allocation in dio write
atomic to avoid above issues.

Test environment:
ubuntu os with linux kernel 4.2+, intel i7-3770, 16g memory,
32g kingston sd card.

fio --name seqw --ioengine=sync --invalidate=1 --rw=write --directory=/mnt/f2fs --filesize=256m --size=16m --bs=2m --direct=1
--numjobs=10

before:
  WRITE: io=163840KB, aggrb=3145KB/s, minb=314KB/s, maxb=411KB/s, mint=39836msec, maxt=52083msec

patched:
  WRITE: io=163840KB, aggrb=10033KB/s, minb=1003KB/s, maxb=1124KB/s, mint=14565msec, maxt=16329msec

Signed-off-by: Chao Yu <chao2.yu@...sung.com>
---
 fs/f2fs/data.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index a737ca5..a0a5849 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1536,7 +1536,9 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	size_t count = iov_iter_count(iter);
+	int rw = iov_iter_rw(iter);
 	int err;
 
 	/* we don't need to use inline_data strictly */
@@ -1555,12 +1557,17 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 
 	trace_f2fs_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
 
-	if (iov_iter_rw(iter) == WRITE)
+	if (rw == WRITE) {
+		mutex_lock(&sbi->writepages);
 		__allocate_data_blocks(inode, offset, count);
+	}
 
 	err = blockdev_direct_IO(iocb, inode, iter, offset, get_data_block_dio);
-	if (err < 0 && iov_iter_rw(iter) == WRITE)
-		f2fs_write_failed(mapping, offset + count);
+	if (rw == WRITE) {
+		mutex_unlock(&sbi->writepages);
+		if (err)
+			f2fs_write_failed(mapping, offset + count);
+	}
 
 	trace_f2fs_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), err);
 
-- 
2.4.2


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

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ