On 15 Feb 2024, at 11:57, Vlastimil Babka wrote:
> On 2/14/24 23:04, Zi Yan wrote:
>> @@ -1849,10 +1857,22 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data)
>> static void compaction_free(struct folio *dst, unsigned long data)
>> {
>> struct compact_control *cc = (struct compact_control *)data;
>> + int order = folio_order(dst);
>> + struct page *page = &dst->page;
>> +
>> + if (folio_put_testzero(dst)) {
>> + free_pages_prepare_fpi_none(page, order);
>> +
>> + INIT_LIST_HEAD(&dst->lru);
>
> (is this even needed? I think the state of first parameter of list_add() is
> never expected to be in particular state?)
There is a __list_add_valid() performing list corruption checks.
>
>>
>> - list_add(&dst->lru, &cc->freepages);
>> - cc->nr_freepages++;
>> - cc->nr_migratepages += 1 << folio_order(dst);
>> + list_add(&dst->lru, &cc->freepages[order]);
>> + cc->nr_freepages += 1 << order;
>> + cc->nr_migratepages += 1 << order;
>
> Hm actually this increment of nr_migratepages should happen even if we lost
> the free page.
Because compaction_free() indicates the page is not migrated and nr_migratepages
should be increased regardless.
Will fix it. Thanks.
>> + }
>> + /*
>> + * someone else has referenced the page, we cannot take it back to our
>> + * free list.
>> + */
>> }
--
Best Regards,
Yan, Zi
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