Unverified Commit 7feb1eea authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!893 mitigatin cacheline false sharing 

Merge Pull Request from: @zhangjialin11 
 
In the test of execl, shell1 and shell8 of UnixBench, L3 false sharing occurs between rwsem_try_write_lock_unqueued() and filemap_map_pages().

The offset between address_space.host and address_space.i_mmap_rwsem is 48. It may occur L3 false sharing. Their offsets in struct ext4_inode_info is 696 and 744, so when the address of ext4_inode_info after L3 aligned, it may occur L3 false sharing in the following condition:

[0x00 ~ 0x10] false sharing
[0x18 ~ 0x40] no false sharing
[0x48 ~ 0x80] false sharing

Change the offset of 'vfs_inode' from 320 to 360 in ext4_inode_info and make the address of ext4_inode_info L3 aligned, so the offset of host and i_mmap_rwsem in ext4_inode_info is changed to 736 and 784, it can make them in different L3 to avoid false sharing.

./Run -c 96 -i 3 execl

Before this patch:
System Benchmarks Partial Index              BASELINE       RESULT    INDEX
Execl Throughput                                 43.0      24238.0   5636.8
                                                                   ========
System Benchmarks Index Score (Partial Only)                         5636.8

After this patch:
System Benchmarks Partial Index              BASELINE       RESULT    INDEX
Execl Throughput                                 43.0      29363.7   6828.8
                                                                   ========
System Benchmarks Index Score (Partial Only)                         6828.8 
 
Link:https://gitee.com/openeuler/kernel/pulls/893

 

Reviewed-by: default avatarzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parents 4ac8d141 137c85fc

arch/arm64/configs/openeuler_defconfig

+1 −0
Original line number Diff line number Diff line
@@ -6211,6 +6211,7 @@ CONFIG_EXT4_USE_FOR_EXT2=y 
CONFIG_EXT4_FS_POSIX_ACL=y

CONFIG_EXT4_FS_SECURITY=y

# CONFIG_EXT4_DEBUG is not set

CONFIG_EXT4_MITIGATION_FALSE_SHARING=y

CONFIG_JBD2=m

# CONFIG_JBD2_DEBUG is not set

CONFIG_FS_MBCACHE=m

arch/x86/configs/openeuler_defconfig

+1 −0
Original line number Diff line number Diff line
@@ -7308,6 +7308,7 @@ CONFIG_EXT4_USE_FOR_EXT2=y 
CONFIG_EXT4_FS_POSIX_ACL=y

CONFIG_EXT4_FS_SECURITY=y

# CONFIG_EXT4_DEBUG is not set

CONFIG_EXT4_MITIGATION_FALSE_SHARING=y

CONFIG_JBD2=m

# CONFIG_JBD2_DEBUG is not set

CONFIG_FS_MBCACHE=m

fs/ext4/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -117,3 +117,12 @@ config EXT4_KUNIT_TESTS 
	  to the KUnit documentation in Documentation/dev-tools/kunit/.



	  If unsure, say N.



config EXT4_MITIGATION_FALSE_SHARING

	bool "mitigation false sharing in ext4 inode"

	depends on EXT4_FS

	default n

	help

	  Enable this to mitigation cacheline false sharing in ext4 inode info.



	  If unsure, say N.

fs/ext4/ext4.h

+5 −0
Original line number Diff line number Diff line
@@ -1090,7 +1090,9 @@ struct ext4_inode_info { 
	 * to occasionally drop it.

	 */

	struct rw_semaphore i_mmap_sem;

#ifndef CONFIG_EXT4_MITIGATION_FALSE_SHARING

	struct inode vfs_inode;

#endif

	struct jbd2_inode *jinode;



	spinlock_t i_raw_lock;	/* protects updates to the raw inode */
@@ -1103,6 +1105,9 @@ struct ext4_inode_info { 


	/* mballoc */

	atomic_t i_prealloc_active;

#ifdef CONFIG_EXT4_MITIGATION_FALSE_SHARING

	struct inode vfs_inode;

#endif

	struct list_head i_prealloc_list;

	spinlock_t i_prealloc_lock;

fs/ext4/super.c

+4 −0
Original line number Diff line number Diff line
@@ -1420,7 +1420,11 @@ static void init_once(void *foo) 
static int __init init_inodecache(void)

{

	ext4_inode_cachep = kmem_cache_create_usercopy("ext4_inode_cache",

#ifdef CONFIG_EXT4_MITIGATION_FALSE_SHARING

				sizeof(struct ext4_inode_info), 128,

#else

				sizeof(struct ext4_inode_info), 0,

#endif

				(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|

					SLAB_ACCOUNT),

				offsetof(struct ext4_inode_info, i_data),