From cb29a02d3a9d51c749f556b3bbf6551fbc0454eb Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 14 Jul 2020 16:09:09 -0700 Subject: ext4: use generic names for generic ioctls Don't define EXT4_IOC_* aliases to ioctls that already have a generic FS_IOC_* name. These aliases are unnecessary, and they make it unclear which ioctls are ext4-specific and which are generic. Exception: leave EXT4_IOC_GETVERSION_OLD and EXT4_IOC_SETVERSION_OLD as-is for now, since renaming them to FS_IOC_GETVERSION and FS_IOC_SETVERSION would probably make them more likely to be confused with EXT4_IOC_GETVERSION and EXT4_IOC_SETVERSION which also exist. Signed-off-by: Eric Biggers Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20200714230909.56349-1-ebiggers@kernel.org Signed-off-by: Theodore Ts'o --- Documentation/admin-guide/ext4.rst | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) (limited to 'Documentation/admin-guide/ext4.rst') diff --git a/Documentation/admin-guide/ext4.rst b/Documentation/admin-guide/ext4.rst index 9443fcef1876..7fc6a72920c9 100644 --- a/Documentation/admin-guide/ext4.rst +++ b/Documentation/admin-guide/ext4.rst @@ -522,21 +522,21 @@ Files in /sys/fs/ext4/: Ioctls ====== -There is some Ext4 specific functionality which can be accessed by applications -through the system call interfaces. The list of all Ext4 specific ioctls are -shown in the table below. +Ext4 implements various ioctls which can be used by applications to access +ext4-specific functionality. An incomplete list of these ioctls is shown in the +table below. This list includes truly ext4-specific ioctls (``EXT4_IOC_*``) as +well as ioctls that may have been ext4-specific originally but are now supported +by some other filesystem(s) too (``FS_IOC_*``). -Table of Ext4 specific ioctls +Table of Ext4 ioctls - EXT4_IOC_GETFLAGS + FS_IOC_GETFLAGS Get additional attributes associated with inode. The ioctl argument is - an integer bitfield, with bit values described in ext4.h. This ioctl is - an alias for FS_IOC_GETFLAGS. + an integer bitfield, with bit values described in ext4.h. - EXT4_IOC_SETFLAGS + FS_IOC_SETFLAGS Set additional attributes associated with inode. The ioctl argument is - an integer bitfield, with bit values described in ext4.h. This ioctl is - an alias for FS_IOC_SETFLAGS. + an integer bitfield, with bit values described in ext4.h. EXT4_IOC_GETVERSION, EXT4_IOC_GETVERSION_OLD Get the inode i_generation number stored for each inode. The -- cgit From 27bc446e2def38db3244a6eb4bb1d6312936610a Mon Sep 17 00:00:00 2001 From: brookxu Date: Mon, 17 Aug 2020 15:36:15 +0800 Subject: ext4: limit the length of per-inode prealloc list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In the scenario of writing sparse files, the per-inode prealloc list may be very long, resulting in high overhead for ext4_mb_use_preallocated(). To circumvent this problem, we limit the maximum length of per-inode prealloc list to 512 and allow users to modify it. After patching, we observed that the sys ratio of cpu has dropped, and the system throughput has increased significantly. We created a process to write the sparse file, and the running time of the process on the fixed kernel was significantly reduced, as follows: Running time on unfixed kernel： [root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat real 0m2.051s user 0m0.008s sys 0m2.026s Running time on fixed kernel： [root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat real 0m0.471s user 0m0.004s sys 0m0.395s Signed-off-by: Chunguang Xu Link: https://lore.kernel.org/r/d7a98178-056b-6db5-6bce-4ead23f4a257@gmail.com Signed-off-by: Theodore Ts'o --- Documentation/admin-guide/ext4.rst | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation/admin-guide/ext4.rst') diff --git a/Documentation/admin-guide/ext4.rst b/Documentation/admin-guide/ext4.rst index 7fc6a72920c9..59bcc4a92602 100644 --- a/Documentation/admin-guide/ext4.rst +++ b/Documentation/admin-guide/ext4.rst @@ -482,6 +482,9 @@ Files in /sys/fs/ext4/: multiple of this tuning parameter if the stripe size is not set in the ext4 superblock + mb_max_inode_prealloc + The maximum length of per-inode ext4_prealloc_space list. + mb_max_to_scan The maximum number of extents the multiblock allocator will search to find the best extent. -- cgit