From: Oscar Salvador <osalvador@suse.de>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@suse.com>,
Shakeel Butt <shakeelb@google.com>,
David Hildenbrand <david@redhat.com>,
Muchun Song <songmuchun@bytedance.com>,
David Rientjes <rientjes@google.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Peter Zijlstra <peterz@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
HORIGUCHI NAOYA <naoya.horiguchi@nec.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Waiman Long <longman@redhat.com>, Peter Xu <peterx@redhat.com>,
Mina Almasry <almasrymina@google.com>,
Hillf Danton <hdanton@sina.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Barry Song <song.bao.hua@hisilicon.com>,
Will Deacon <will@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v4 4/8] hugetlb: create remove_hugetlb_page() to separate functionality
Date: Tue, 6 Apr 2021 15:41:07 +0200 [thread overview]
Message-ID: <YGxk85nXJD+NxzYX@localhost.localdomain> (raw)
In-Reply-To: <20210405230043.182734-5-mike.kravetz@oracle.com>
On Mon, Apr 05, 2021 at 04:00:39PM -0700, Mike Kravetz wrote:
> +static void remove_hugetlb_page(struct hstate *h, struct page *page,
> + bool adjust_surplus)
> +{
> + int nid = page_to_nid(page);
> +
> + if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
> + return;
> +
> + list_del(&page->lru);
> +
> + if (HPageFreed(page)) {
> + h->free_huge_pages--;
> + h->free_huge_pages_node[nid]--;
> + ClearHPageFreed(page);
> + }
> + if (adjust_surplus) {
> + h->surplus_huge_pages--;
> + h->surplus_huge_pages_node[nid]--;
> + }
> +
> + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
> + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
These checks feel a bit odd here.
I would move them above, before we start messing with the counters?
> +
> + ClearHPageTemporary(page);
Why clearing it unconditionally? I guess we do not really care, but
someone might wonder why when reading the core.
So I would either do as we used to do and only clear it in case of
HPageTemporary(), or drop a comment.
> + set_page_refcounted(page);
> + set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
> +
> + h->nr_huge_pages--;
> + h->nr_huge_pages_node[nid]--;
> +}
As Michal pointed out, remove_hugetlb_page() from
alloc_and_dissolve_huge_page() might be problematic in some cases because
the new_page has not been enqueued yet.
Now, I guess this might be easily fixed with checking list_empty()
before going ahead with list_del() call, or with another bool parameter
'delete', with a fat comment explaining why we can get to call remove_huge_page()
on a page that is not in any list.
Another solution that comes to my mind is to split remove_huge_page() functionality in
1) delete from list + unaccount free and surplus pages and 2) reset page's state + unaccount
nr_huge_pages
But that might be just biased as would fit for my usecase.
So maybe a list_empty() or the bool parameter might just do.
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-04-06 13:41 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-05 23:00 [PATCH v4 0/8] make hugetlb put_page safe for all calling contexts Mike Kravetz
2021-04-05 23:00 ` [PATCH v4 1/8] mm/cma: change cma mutex to irq safe spinlock Mike Kravetz
2021-04-06 9:17 ` Peter Zijlstra
2021-04-06 9:35 ` Michal Hocko
2021-04-07 9:23 ` David Hildenbrand
2021-04-07 18:24 ` Roman Gushchin
2021-04-05 23:00 ` [PATCH v4 2/8] hugetlb: no need to drop hugetlb_lock to call cma_release Mike Kravetz
2021-04-06 7:18 ` Oscar Salvador
2021-04-07 9:26 ` David Hildenbrand
2021-04-05 23:00 ` [PATCH v4 3/8] hugetlb: add per-hstate mutex to synchronize user adjustments Mike Kravetz
2021-04-07 9:28 ` David Hildenbrand
2021-04-05 23:00 ` [PATCH v4 4/8] hugetlb: create remove_hugetlb_page() to separate functionality Mike Kravetz
2021-04-06 9:56 ` Michal Hocko
2021-04-06 12:50 ` Oscar Salvador
2021-04-06 16:49 ` Mike Kravetz
2021-04-06 17:57 ` Oscar Salvador
2021-04-07 8:21 ` Michal Hocko
2021-04-06 13:41 ` Oscar Salvador [this message]
2021-04-06 20:52 ` Mike Kravetz
2021-04-06 13:44 ` Oscar Salvador
2021-04-05 23:00 ` [PATCH v4 5/8] hugetlb: call update_and_free_page without hugetlb_lock Mike Kravetz
2021-04-06 9:57 ` Michal Hocko
2021-04-07 8:27 ` Oscar Salvador
2021-04-07 9:28 ` Michal Hocko
2021-04-07 9:37 ` Oscar Salvador
2021-04-05 23:00 ` [PATCH v4 6/8] hugetlb: change free_pool_huge_page to remove_pool_huge_page Mike Kravetz
2021-04-07 8:44 ` Oscar Salvador
2021-04-05 23:00 ` [PATCH v4 7/8] hugetlb: make free_huge_page irq safe Mike Kravetz
2021-04-07 9:12 ` Oscar Salvador
2021-04-07 9:33 ` Michal Hocko
2021-04-07 9:38 ` Oscar Salvador
2021-04-05 23:00 ` [PATCH v4 8/8] hugetlb: add lockdep_assert_held() calls for hugetlb_lock Mike Kravetz
2021-04-07 9:13 ` Oscar Salvador
2021-04-08 0:56 ` [PATCH v4 0/8] make hugetlb put_page safe for all calling contexts Mike Kravetz
2021-04-08 7:11 ` Oscar Salvador
2021-04-09 5:05 ` Andrew Morton
2021-04-09 20:43 ` Mike Kravetz
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