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mm/cma_debug: show complete cma name in debugfs directories

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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@quicinc.com
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavan Kondeti <quic_pkondeti@quicinc.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Charan Teja Kalla 2022-08-11 18:45:29 +05:30 committed by Andrew Morton
parent cf1e3fe497
commit 9a79443ddc
2 changed files with 6 additions and 9 deletions
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10
Documentation/admin-guide/mm/cma_debugfs.rst
View file

@ -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 that directory is as follows:
- [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.

5
mm/cma_debug.c
View file

@ -163,11 +163,8 @@ DEFINE_DEBUGFS_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
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);