The patch titled
Subject: mm/cma_debug: show complete cma name in debugfs directories
has been added to the -mm mm-unstable branch. Its filename is
mm-cma_debug-show-complete-cma-name-in-debugfs-directories.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-cma_debug-show-complete-cma-name-in-debugfs-directories.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Charan Teja Kalla <quic_charante@xxxxxxxxxxx>
Subject: mm/cma_debug: show complete cma name in debugfs directories
Date: Thu, 11 Aug 2022 18:45:29 +0530
Currently only 12 characters of the cma name is being used as the debug
directories where as the cma name can be of length CMA_MAX_NAME(=64)
characters. One side problem with this is having 2 cma's with first
common 12 characters would end up in trying to create directories with
same name and fails with -EEXIST thus can limit cma debug functionality.
The 'cma-' prefix is used initially where cma areas don't have any names
and are represented by simple integer values. Since now each cma would be
having its own name, drop 'cma-' prefix for the cma debug directories as
they are clearly evident that they are for cma debug through creating them
in /sys/kernel/debug/cma/ path.
Link: https://lkml.kernel.org/r/1660223729-22461-1-git-send-email-quic_charante@xxxxxxxxxxx
Signed-off-by: Charan Teja Kalla <quic_charante@xxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Pavan Kondeti <quic_pkondeti@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/mm/cma_debugfs.rst | 10 +++++-----
mm/cma_debug.c | 5 +----
2 files changed, 6 insertions(+), 9 deletions(-)
--- a/Documentation/admin-guide/mm/cma_debugfs.rst~mm-cma_debug-show-complete-cma-name-in-debugfs-directories
+++ a/Documentation/admin-guide/mm/cma_debugfs.rst
@@ -5,10 +5,10 @@ CMA Debugfs Interface
The CMA debugfs interface is useful to retrieve basic information out of the
different CMA areas and to test allocation/release in each of the areas.
-Each CMA zone represents a directory under <debugfs>/cma/, indexed by the
-kernel's CMA index. So the first CMA zone would be:
+Each CMA area represents a directory under <debugfs>/cma/, represented by
+its CMA name like below:
- <debugfs>/cma/cma-0
+ <debugfs>/cma/<cma_name>
The structure of the files created under that directory is as follows:
@@ -18,8 +18,8 @@ The structure of the files created under
- [RO] bitmap: The bitmap of page states in the zone.
- [WO] alloc: Allocate N pages from that CMA area. For example::
- echo 5 > <debugfs>/cma/cma-2/alloc
+ echo 5 > <debugfs>/cma/<cma_name>/alloc
-would try to allocate 5 pages from the cma-2 area.
+would try to allocate 5 pages from the 'cma_name' area.
- [WO] free: Free N pages from that CMA area, similar to the above.
--- a/mm/cma_debug.c~mm-cma_debug-show-complete-cma-name-in-debugfs-directories
+++ a/mm/cma_debug.c
@@ -163,11 +163,8 @@ DEFINE_DEBUGFS_ATTRIBUTE(cma_alloc_fops,
static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry)
{
struct dentry *tmp;
- char name[CMA_MAX_NAME];
- scnprintf(name, sizeof(name), "cma-%s", cma->name);
-
- tmp = debugfs_create_dir(name, root_dentry);
+ tmp = debugfs_create_dir(cma->name, root_dentry);
debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops);
debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops);
_
Patches currently in -mm which might be from quic_charante@xxxxxxxxxxx are
mm-page_ext-remove-unused-variable-in-offline_page_ext.patch
mm-fix-use-after-free-of-page_ext-after-race-with-memory-offline.patch
mm-cma_debug-show-complete-cma-name-in-debugfs-directories.patch
