From: Oscar Salvador <osalvador@suse.de>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Michal Hocko <mhocko@kernel.org>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Muchun Song <songmuchun@bytedance.com>,
David Hildenbrand <david@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2 4/5] hugetlb: convert PageHugeTemporary() to HPageTemporary flag
Date: Wed, 20 Jan 2021 11:09:13 +0100 [thread overview]
Message-ID: <20210120100913.GC4752@localhost.localdomain> (raw)
In-Reply-To: <20210120013049.311822-5-mike.kravetz@oracle.com>
On Tue, Jan 19, 2021 at 05:30:48PM -0800, Mike Kravetz wrote:
> Use new hugetlb specific HPageTemporary flag to replace the
> PageHugeTemporary() interfaces.
>
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
I would have added a brief comment explaining why it is ok to drop
the PageHuge() check in PageHugeTemporary.
AFAICS, the paths checking it already know they are handling with a
hugetlb page, but still it is better to mention it in the changelog
in case someone wonders.
Other than that looks good to me:
Reviewed-by: Oscar Salvador <osalvador@suse.de>
> ---
> include/linux/hugetlb.h | 6 ++++++
> mm/hugetlb.c | 36 +++++++-----------------------------
> 2 files changed, 13 insertions(+), 29 deletions(-)
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 1e17529c8b81..ec329b9cc0fc 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -483,10 +483,15 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
> * HPG_migratable - Set after a newly allocated page is added to the page
> * cache and/or page tables. Indicates the page is a candidate for
> * migration.
> + * HPG_temporary - - Set on a page that is temporarily allocated from the buddy
> + * allocator. Typically used for migration target pages when no pages
> + * are available in the pool. The hugetlb free page path will
> + * immediately free pages with this flag set to the buddy allocator.
> */
> enum hugetlb_page_flags {
> HPG_restore_reserve = 0,
> HPG_migratable,
> + HPG_temporary,
> __NR_HPAGEFLAGS,
> };
>
> @@ -534,6 +539,7 @@ static inline void ClearHPage##uname(struct page *page) \
> */
> HPAGEFLAG(RestoreReserve, restore_reserve)
> HPAGEFLAG(Migratable, migratable)
> +HPAGEFLAG(Temporary, temporary)
>
> #ifdef CONFIG_HUGETLB_PAGE
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 6e32751489e8..0d2bfc2b6adc 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1353,28 +1353,6 @@ struct hstate *size_to_hstate(unsigned long size)
> return NULL;
> }
>
> -/*
> - * Internal hugetlb specific page flag. Do not use outside of the hugetlb
> - * code
> - */
> -static inline bool PageHugeTemporary(struct page *page)
> -{
> - if (!PageHuge(page))
> - return false;
> -
> - return (unsigned long)page[2].mapping == -1U;
> -}
> -
> -static inline void SetPageHugeTemporary(struct page *page)
> -{
> - page[2].mapping = (void *)-1U;
> -}
> -
> -static inline void ClearPageHugeTemporary(struct page *page)
> -{
> - page[2].mapping = NULL;
> -}
> -
> static void __free_huge_page(struct page *page)
> {
> /*
> @@ -1422,9 +1400,9 @@ static void __free_huge_page(struct page *page)
> if (restore_reserve)
> h->resv_huge_pages++;
>
> - if (PageHugeTemporary(page)) {
> + if (HPageTemporary(page)) {
> list_del(&page->lru);
> - ClearPageHugeTemporary(page);
> + ClearHPageTemporary(page);
> update_and_free_page(h, page);
> } else if (h->surplus_huge_pages_node[nid]) {
> /* remove the page from active list */
> @@ -1863,7 +1841,7 @@ static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
> * codeflow
> */
> if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
> - SetPageHugeTemporary(page);
> + SetHPageTemporary(page);
> spin_unlock(&hugetlb_lock);
> put_page(page);
> return NULL;
> @@ -1894,7 +1872,7 @@ static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
> * We do not account these pages as surplus because they are only
> * temporary and will be released properly on the last reference
> */
> - SetPageHugeTemporary(page);
> + SetHPageTemporary(page);
>
> return page;
> }
> @@ -5607,12 +5585,12 @@ void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
> * here as well otherwise the global surplus count will not match
> * the per-node's.
> */
> - if (PageHugeTemporary(newpage)) {
> + if (HPageTemporary(newpage)) {
> int old_nid = page_to_nid(oldpage);
> int new_nid = page_to_nid(newpage);
>
> - SetPageHugeTemporary(oldpage);
> - ClearPageHugeTemporary(newpage);
> + SetHPageTemporary(oldpage);
> + ClearHPageTemporary(newpage);
>
> spin_lock(&hugetlb_lock);
> if (h->surplus_huge_pages_node[old_nid]) {
> --
> 2.29.2
>
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-01-20 10:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 1:30 [PATCH v2 0/5] create hugetlb flags to consolidate state Mike Kravetz
2021-01-20 1:30 ` [PATCH v2 1/5] hugetlb: use page.private for hugetlb specific page flags Mike Kravetz
2021-01-20 8:10 ` Miaohe Lin
2021-01-20 8:43 ` kernel test robot
2021-01-20 9:30 ` Oscar Salvador
2021-01-20 18:12 ` Mike Kravetz
2021-01-20 1:30 ` [PATCH v2 2/5] hugetlb: convert page_huge_active() HPageMigratable flag Mike Kravetz
2021-01-20 9:59 ` Oscar Salvador
2021-01-20 10:00 ` Oscar Salvador
2021-01-20 21:48 ` Mike Kravetz
2021-01-21 8:18 ` Oscar Salvador
2021-01-21 8:27 ` Oscar Salvador
2021-01-21 12:01 ` [External] " Muchun Song
2021-01-22 6:53 ` Miaohe Lin
2021-01-22 23:12 ` Mike Kravetz
2021-02-03 7:42 ` [External] " Muchun Song
2021-02-04 0:44 ` Mike Kravetz
2021-01-20 1:30 ` [PATCH v2 3/5] hugetlb: only set HPageMigratable for migratable hstates Mike Kravetz
2021-01-20 1:30 ` [PATCH v2 4/5] hugetlb: convert PageHugeTemporary() to HPageTemporary flag Mike Kravetz
2021-01-20 10:09 ` Oscar Salvador [this message]
2021-01-20 18:14 ` Mike Kravetz
2021-01-20 1:30 ` [PATCH v2 5/5] hugetlb: convert PageHugeFreed to HPageFreed flag Mike Kravetz
2021-01-20 10:10 ` Oscar Salvador
2021-01-20 10:44 ` [External] " Muchun Song
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