Commit 48774b90 authored by Zhihao Cheng's avatar Zhihao Cheng
Browse files

ext4: Optimize endio process for DIO overwrites 

hulk inclusion
category: perf
bugzilla: https://gitee.com/openeuler/kernel/issues/I90ZB5


CVE: NA

--------------------------------

In DIO overwriting case, there is no need to convert unwritten exntents
and ext4_handle_inode_extension() can be ignored, which means that endio
process can be executed under irq context. Since commit 240930fb
("ext4: dio take shared inode lock when overwriting preallocated blocks")
has provided a method to judge whether overwriting is happening, just do
nothing in endio process if DIO overwriting happens.
This patch enables ext4 processing endio under irq context in DIO
overwriting case, which brings a performance improvement in the
following fio test on a x86 physical machine with nvme when irq
and fio run on the same cpu:

Test: fio -direct=1 -iodepth=128 -rw=randwrite -ioengine=libaio -bs=4k
-size=2G -numjobs=1 -overwrite=1 -time_based -runtime=60 -group_reporting
-filename=/test/test -name=Rand_write_Testing --cpus_allowed=1

before: 953 MiB/s  after: 1350 MiB/s, ~41% perf improvement.

Suggested-by: default avatarZhang Yi <yi.zhang@huawei.com>
Signed-off-by: default avatarZhihao Cheng <chengzhihao1@huawei.com>
parent 6424cf07

fs/ext4/file.c

+8 −3
Original line number Diff line number Diff line
@@ -478,8 +478,10 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) 
	loff_t offset = iocb->ki_pos;

	size_t count = iov_iter_count(from);

	const struct iomap_ops *iomap_ops = &ext4_iomap_ops;

	const struct iomap_dio_ops *iomap_dops = &ext4_dio_write_ops;

	bool extend = false, unaligned_io = false;

	bool ilock_shared = true;

	int dio_flags = 0;



	/*

	 * We initially start with shared inode lock unless it is
@@ -569,10 +571,13 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) 
		ext4_journal_stop(handle);

	}



	if (ilock_shared)

	if (ilock_shared) {

		iomap_ops = &ext4_iomap_overwrite_ops;

	ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,

			   (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0);

		iomap_dops = NULL;

		dio_flags = IOMAP_DIO_MAY_INLINE_COMP;

	} else if (unaligned_io || extend)

		dio_flags |= IOMAP_DIO_FORCE_WAIT;

	ret = iomap_dio_rw(iocb, from, iomap_ops, iomap_dops, dio_flags);

	if (ret == -ENOTBLK)

		ret = 0;