mbox series

[v3,0/8] Fixes and cleanups to compaction

Message ID 20230804110454.2935878-1-shikemeng@huaweicloud.com (mailing list archive)
Headers show
Series Fixes and cleanups to compaction | expand

Message

Kemeng Shi Aug. 4, 2023, 11:04 a.m. UTC
Hi all, this series contains some random cleanups and fixes to
compation. Details can be found in respective patches.

v2->v3:
-Improve comment in patch 4
-Collect ACK and RVB from David and Baolin.
-Rebase code on current mm-unstable

v1->v2:
-Add comment to skip_offline_sections_reverse in patch 1
-Add impact in git message in patch 2
-Correct comment to fast_find_block instead of remove fast_find_block
in patch 4
-Collect RVB from David and Baolin.

Kemeng Shi (8):
  mm/compaction: avoid missing last page block in section after skip
    offline sections
  mm/compaction: correct last_migrated_pfn update in compact_zone
  mm/compaction: skip page block marked skip in
    isolate_migratepages_block
  mm/compaction: correct comment of fast_find_migrateblock in
    isolate_migratepages
  mm/compaction: correct comment of cached migrate pfn update
  mm/compaction: correct comment to complete migration failure
  mm/compaction: remove unnecessary return for void function
  mm/compaction: only set skip flag if cc->no_set_skip_hint is false

 mm/compaction.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

Comments

Baolin Wang Aug. 7, 2023, 9:41 a.m. UTC | #1
On 8/4/2023 7:04 PM, Kemeng Shi wrote:
> skip_offline_sections_reverse will return the last pfn in found online
> section. Then we set block_start_pfn to start of page block which
> contains the last pfn in section. Then we continue, move one page
> block forward and ignore the last page block in the online section.
> Make block_start_pfn point to first page block after online section to fix
> this:
> 1. make skip_offline_sections_reverse return end pfn of online section,
> i.e. pfn of page block after online section.
> 2. assign block_start_pfn with next_pfn.
> 
> Fixes: f63224525309 ("mm: compaction: skip the memory hole rapidly when isolating free pages")

Again, the Fixes tag is not stable. Please consider squashing it into 
the original commit or hold this patch until the original patch is 
merged into mm-stable branch.

Andrew,
What do you prefer? Thanks.

> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> Acked-by: David Hildenbrand <david@redhat.com>
> 
> ---
>   mm/compaction.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 006fc35bffa1..a21b834c5898 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -250,6 +250,11 @@ static unsigned long skip_offline_sections(unsigned long start_pfn)
>   	return 0;
>   }
>   
> +/*
> + * If the PFN falls into an offline section, return the end PFN of the
> + * next online section in reverse. If the PFN falls into an online section
> + * or if there is no next online section in reverse, return 0.
> + */
>   static unsigned long skip_offline_sections_reverse(unsigned long start_pfn)
>   {
>   	unsigned long start_nr = pfn_to_section_nr(start_pfn);
> @@ -259,7 +264,7 @@ static unsigned long skip_offline_sections_reverse(unsigned long start_pfn)
>   
>   	while (start_nr-- > 0) {
>   		if (online_section_nr(start_nr))
> -			return section_nr_to_pfn(start_nr) + PAGES_PER_SECTION - 1;
> +			return section_nr_to_pfn(start_nr) + PAGES_PER_SECTION;
>   	}
>   
>   	return 0;
> @@ -1690,8 +1695,7 @@ static void isolate_freepages(struct compact_control *cc)
>   
>   			next_pfn = skip_offline_sections_reverse(block_start_pfn);
>   			if (next_pfn)
> -				block_start_pfn = max(pageblock_start_pfn(next_pfn),
> -						      low_pfn);
> +				block_start_pfn = max(next_pfn, low_pfn);
>   
>   			continue;
>   		}