2023-10-13 19:05:17

by Audra Mitchell

Subject: [PATCH 1/5] mm/page_owner: Remove free_ts from page_owner output

When printing page_owner data via the sysfs interface, no free pages will
ever be dumped due to the series of checks in read_page_owner():

/*
* Although we do have the info about past allocation of free
* pages, it's not relevant for current memory usage.
*/
if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))

The free_ts values are still used when dump_page_owner() is called, so
keeping the field for other use cases but removing them for the typical
page_owner case.

Fixes: 866b48526217 ("mm/page_owner: record the timestamp of all pages during free")
Signed-off-by: Audra Mitchell <[email protected]>
---
mm/page_owner.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 4e2723e1b300..4f13ce7d2452 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -408,11 +408,11 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
return -ENOMEM;

ret = scnprintf(kbuf, count,
- "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns, free_ts %llu ns\n",
+ "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n",
page_owner->order, page_owner->gfp_mask,
&page_owner->gfp_mask, page_owner->pid,
page_owner->tgid, page_owner->comm,
- page_owner->ts_nsec, page_owner->free_ts_nsec);
+ page_owner->ts_nsec);

/* Print information relevant to grouping pages by mobility */
pageblock_mt = get_pageblock_migratetype(page);
--
2.41.0

2023-10-17 08:07:20

by Vlastimil Babka

Subject: Re: [PATCH 1/5] mm/page_owner: Remove free_ts from page_owner output

On 10/13/23 21:03, Audra Mitchell wrote:
> When printing page_owner data via the sysfs interface, no free pages will
> ever be dumped due to the series of checks in read_page_owner():
>
> /*
> * Although we do have the info about past allocation of free
> * pages, it's not relevant for current memory usage.
> */
> if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
>
> The free_ts values are still used when dump_page_owner() is called, so
> keeping the field for other use cases but removing them for the typical
> page_owner case.
>
> Fixes: 866b48526217 ("mm/page_owner: record the timestamp of all pages during free")
> Signed-off-by: Audra Mitchell <[email protected]>

Reviewed-by: Vlastimil Babka <[email protected]>

> ---
> mm/page_owner.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index 4e2723e1b300..4f13ce7d2452 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -408,11 +408,11 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
> return -ENOMEM;
>
> ret = scnprintf(kbuf, count,
> - "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns, free_ts %llu ns\n",
> + "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n",
> page_owner->order, page_owner->gfp_mask,
> &page_owner->gfp_mask, page_owner->pid,
> page_owner->tgid, page_owner->comm,
> - page_owner->ts_nsec, page_owner->free_ts_nsec);
> + page_owner->ts_nsec);
>
> /* Print information relevant to grouping pages by mobility */
> pageblock_mt = get_pageblock_migratetype(page);