Re: [PATCH v6 1/3] mm/page_owner: add print_mode filter

["zhen.ni" <zhen.ni@easystack.cn>]

在 2026/5/11 16:29, Oscar Salvador 写道:
> On Mon, May 11, 2026 at 11:30:15AM +0800, Zhen Ni wrote:
>> Add a print_mode filter to page_owner that allows users to choose between
>> printing full stack traces or only stack handles, significantly reducing
>> output size for debugging and analysis.
>>
>> The filter provides a string-based interface under
>> /sys/kernel/debug/page_owner_filter/:
>> - Reading shows the current mode with [] brackets around active option
>> - Writing accepts "full_stack" or "stack_handle" strings
>>
>> The default full_stack mode maintains backward compatibility with existing
>> usage, displaying complete stack traces for each page allocation.
>>
>> The stack_handle mode dramatically reduces log size by showing only
>> the handle number instead of the full stack trace. The mapping from
>> handles to actual stack traces can be obtained via the
>> show_stacks_handles interface.
>>
>> Example usage:
>>    # echo stack_handle > /sys/kernel/debug/page_owner_filter/print_mode
>>    # cat /sys/kernel/debug/page_owner_filter/print_mode
>>    full_stack [stack_handle]
>>    # cat /sys/kernel/debug/page_owner
>>    Page allocated via order 0, migratetype Unmovable, gfp_mask 0x1100ca,
>>    pid 1, tgid 1 (systemd), ts 123456789 ns
>>    PFN 0x1000 type Unmovable Block 1 type Unmovable
>>    Flags 0x3fffe800000084(referenced|lru|active|private|node=0|zone=1)
>>    handle: 17432583
>>    ...
>>
>> Reviewed-by: SeongJae Park <sj@kernel.org>
>> Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
> 
> Overall looks good to me, one comment below
> 
> Reviewed-by: Oscar Salvador <osalvador@suse.de>
> 
>> ---
> ...
>> ---
>>   mm/page_owner.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++--
>>   1 file changed, 80 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/page_owner.c b/mm/page_owner.c
>> index 8178e0be557f..27a412c52d41 100644
>> --- a/mm/page_owner.c
>> +++ b/mm/page_owner.c
>> @@ -1,5 +1,6 @@
>>   // SPDX-License-Identifier: GPL-2.0
>>   #include <linux/debugfs.h>
>> +#include <linux/fs.h>
> 
> Why do we need this?
> 
The code already gets <linux/fs.h> indirectly through
<linux/debugfs.h>

I will remove it in v7.

Thanks for catching this!
> 

Best regards,
Zhen