From: Oscar Salvador <osalvador@suse.de>
To: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
David Hildenbrand <david@redhat.com>,
Muchun Song <songmuchun@bytedance.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mm: Make alloc_contig_range handle free hugetlb pages
Date: Fri, 19 Feb 2021 11:14:32 +0100 [thread overview]
Message-ID: <20210219101427.GA19588@linux> (raw)
In-Reply-To: <YC+LWksScdiuPw7X@dhcp22.suse.cz>
On Fri, Feb 19, 2021 at 10:56:42AM +0100, Michal Hocko wrote:
> OK, this should work but I am really wondering whether it wouldn't be
> just simpler to replace the old page by a new one in the free list
> directly. Or is there any reason we have to go through the generic
> helpers path? I mean something like this
>
> new_page = alloc_fresh_huge_page();
> if (!new_page)
> goto fail;
> spin_lock(hugetlb_lock);
> if (!PageHuge(old_page)) {
> /* freed from under us, nothing to do */
> __update_and_free_page(new_page);
> goto unlock;
> }
> list_del(&old_page->lru);
> __update_and_free_page(old_page);
> __enqueue_huge_page(new_page);
> unlock:
> spin_unlock(hugetlb_lock);
>
> This will require to split update_and_free_page and enqueue_huge_page to
> counters independent parts but that shouldn't be a big deal. But it will
> also protect from any races. Not an act of beauty but seems less hackish
> to me.
Yes, I think this would to the trick, and it is race-free.
Let me play with it a bit and see what I can come up with.
Thanks for the valuable insight.
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-02-19 10:16 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-17 10:08 [PATCH 0/2] Make alloc_contig_range handle Hugetlb pages Oscar Salvador
2021-02-17 10:08 ` [PATCH 1/2] mm: Make alloc_contig_range handle free hugetlb pages Oscar Salvador
2021-02-17 13:30 ` Michal Hocko
2021-02-17 13:36 ` David Hildenbrand
2021-02-17 13:50 ` Michal Hocko
2021-02-17 13:53 ` David Hildenbrand
2021-02-17 13:59 ` Michal Hocko
2021-02-17 14:08 ` David Hildenbrand
2021-02-17 14:14 ` Michal Hocko
2021-02-17 14:23 ` Oscar Salvador
2021-02-17 13:42 ` Oscar Salvador
2021-02-17 15:00 ` Michal Hocko
2021-02-18 10:09 ` Oscar Salvador
2021-02-18 12:52 ` Michal Hocko
2021-02-18 13:32 ` Oscar Salvador
2021-02-18 13:59 ` Michal Hocko
2021-02-18 16:53 ` Oscar Salvador
2021-02-19 9:05 ` Oscar Salvador
2021-02-19 9:56 ` Michal Hocko
2021-02-19 10:14 ` Oscar Salvador [this message]
2021-02-19 20:00 ` Mike Kravetz
2021-02-19 10:40 ` Oscar Salvador
2021-02-19 10:55 ` Michal Hocko
2021-02-19 11:17 ` Oscar Salvador
2021-02-19 11:24 ` Michal Hocko
2021-02-17 10:08 ` [PATCH 2/2] mm: Make alloc_contig_range handle in-use " Oscar Salvador
2021-02-17 13:36 ` Michal Hocko
2021-02-17 13:46 ` Oscar Salvador
2021-02-17 13:54 ` Michal Hocko
2021-02-17 15:06 ` Michal Hocko
2021-02-17 15:27 ` Oscar Salvador
2021-02-17 15:33 ` Michal Hocko
2021-02-18 6:01 ` Oscar Salvador
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