perf/x86/intel: Rename DMR offcore_rsp attribute to offmodule_rspgrafted

DMR introduces Offmodule Response events in place of the legacy
Offcore Response events, but it still exposes the inherited
offcore_rsp PMU attribute for programming the corresponding MSR data.

Rename the DMR PMU attribute to offmodule_rsp so the sysfs interface
matches the underlying event name and avoids user & tooling confusion.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/20260917015234.981153-12-dapeng1.mi@linux.intel.com

1 files changed, 37 insertions, 0 deletions

diff --git a/Documentation/filesystems/ext4/inlinedata.rst b/Documentation/filesystems/ext4/inlinedata.rst
new file mode 100644
index 000000000..a728af0d2
--- /dev/null
+++ b/Documentation/filesystems/ext4/inlinedata.rst
@@ -0,0 +1,37 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Inline Data
+-----------
+
+The inline data feature was designed to handle the case that a file's
+data is so tiny that it readily fits inside the inode, which
+(theoretically) reduces disk block consumption and reduces seeks. If the
+file is smaller than 60 bytes, then the data are stored inline in
+``inode.i_block``. If the rest of the file would fit inside the extended
+attribute space, then it might be found as an extended attribute
+“system.data” within the inode body (“ibody EA”). This of course
+constrains the amount of extended attributes one can attach to an inode.
+If the data size increases beyond i_block + ibody EA, a regular block
+is allocated and the contents moved to that block.
+
+Pending a change to compact the extended attribute key used to store
+inline data, one ought to be able to store 160 bytes of data in a
+256-byte inode (as of June 2015, when i_extra_isize is 28). Prior to
+that, the limit was 156 bytes due to inefficient use of inode space.
+
+The inline data feature requires the presence of an extended attribute
+for “system.data”, even if the attribute value is zero length.
+
+Inline Directories
+~~~~~~~~~~~~~~~~~~
+
+The first four bytes of i_block are the inode number of the parent
+directory. Following that is a 56-byte space for an array of directory
+entries; see ``struct ext4_dir_entry``. If there is a “system.data”
+attribute in the inode body, the EA value is an array of
+``struct ext4_dir_entry`` as well. Note that for inline directories, the
+i_block and EA space are treated as separate dirent blocks; directory
+entries cannot span the two.
+
+Inline directory entries are not checksummed, as the inode checksum
+should protect all inline data contents.