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

[zhen.ni]

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@xxxxxxxxxx>
> > Signed-off-by: Zhen Ni <zhen.ni@xxxxxxxxxxxx>
>
> Overall looks good to me, one comment below
>
> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
>
> > ---
> ...
> > ---
> >   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