On 3/20/24 7:02 PM, Johannes Weiner wrote:
> Free page accounting currently happens a bit too high up the call
> stack, where it has to deal with guard pages, compaction capturing,
> block stealing and even page isolation. This is subtle and fragile,
> and makes it difficult to hack on the code.
>
> Now that type violations on the freelists have been fixed, push the
> accounting down to where pages enter and leave the freelist.
Awesome!
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Just some nits:
> @@ -1314,10 +1349,10 @@ static inline void expand(struct zone *zone, struct page *page,
> * Corresponding page table entries will not be touched,
> * pages will stay not present in virtual address space
> */
> - if (set_page_guard(zone, &page[size], high, migratetype))
> + if (set_page_guard(zone, &page[size], high))
> continue;
>
> - add_to_free_list(&page[size], zone, high, migratetype);
> + add_to_free_list(&page[size], zone, high, migratetype, false);
This is account_freepages() in the hot loop, what if we instead used
__add_to_free_list(), sum up nr_pages and called account_freepages() once
outside of the loop?
> set_buddy_order(&page[size], high);
> }
> }
<snip>
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 042937d5abe4..914a71c580d8 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -252,7 +252,8 @@ static void unset_migratetype_isolate(struct page *page, int migratetype)
> * Isolating this block already succeeded, so this
> * should not fail on zone boundaries.
> */
> - WARN_ON_ONCE(!move_freepages_block_isolate(zone, page, migratetype));
> + WARN_ON_ONCE(!move_freepages_block_isolate(zone, page,
> + migratetype));
> } else {
> set_pageblock_migratetype(page, migratetype);
> __putback_isolated_page(page, order, migratetype);
Looks like a drive-by edit of an extra file just to adjust identation.
