From: Michal Hocko <mhocko@suse.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
David Hildenbrand <david@redhat.com>,
Muchun Song <songmuchun@bytedance.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 4/5] mm: Make alloc_contig_range handle in-use hugetlb pages
Date: Thu, 18 Mar 2021 11:12:28 +0100 [thread overview]
Message-ID: <YFMnjI+nihUKzAiw@dhcp22.suse.cz> (raw)
In-Reply-To: <YFMkbuUbsLti5P6a@localhost.localdomain>
On Thu 18-03-21 10:59:10, Oscar Salvador wrote:
> On Thu, Mar 18, 2021 at 10:29:57AM +0100, Michal Hocko wrote:
> > On Thu 18-03-21 09:54:01, Oscar Salvador wrote:
> > [...]
> > > @@ -2287,10 +2288,12 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page)
> > > goto unlock;
> > > } else if (page_count(old_page)) {
> > > /*
> > > - * Someone has grabbed the page, fail for now.
> > > + * Someone has grabbed the page, try to isolate it here.
> > > + * Fail with -EBUSY if not possible.
> > > */
> > > - ret = -EBUSY;
> > > update_and_free_page(h, new_page);
> > > + if (!isolate_huge_page(old_page, list)
> > > + ret = -EBUSY;
> > > goto unlock;
> > > } else if (!HPageFreed(old_page)) {
> >
> > I do not think you want to call isolate_huge_page with hugetlb_lock
> > held. You would need to drop the lock before calling isolate_huge_page.
>
> Yeah, that was an oversight. As I said I did not compile it(let alone
> test it), otherwise the system would have screamed I guess.
>
> I was more interested in knowing whether how did it look wrt. retry
> concerns:
Yes this looks much more to my taste. If we need to retry then it could
just goto retry there. The caller doesn't really have to care.
> @@ -2287,10 +2288,14 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page)
> goto unlock;
> } else if (page_count(old_page)) {
> /*
> - * Someone has grabbed the page, fail for now.
> + * Someone has grabbed the page, try to isolate it here.
> + * Fail with -EBUSY if not possible.
> */
> - ret = -EBUSY;
> update_and_free_page(h, new_page);
> + spin_unlock(&hugetlb_lock);
> + if (!isolate_huge_page(old_page, list)
> + ret = -EBUSY;
> + spin_lock(&hugetlb_lock);
> goto unlock;
simply return ret; here
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-03-18 10:13 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-17 11:12 [PATCH v5 0/5] Make alloc_contig_range handle Hugetlb pages Oscar Salvador
2021-03-17 11:12 ` [PATCH v5 1/5] mm,page_alloc: Bail out earlier on -ENOMEM in alloc_contig_migrate_range Oscar Salvador
2021-03-17 14:05 ` Michal Hocko
2021-03-17 14:42 ` David Hildenbrand
2021-03-17 14:49 ` Michal Hocko
2021-03-18 11:04 ` Oscar Salvador
2021-03-18 11:37 ` Michal Hocko
2021-03-17 11:12 ` [PATCH v5 2/5] mm,compaction: Let isolate_migratepages_{range,block} return error codes Oscar Salvador
2021-03-17 14:12 ` Michal Hocko
2021-03-17 14:38 ` Oscar Salvador
2021-03-17 14:59 ` Michal Hocko
2021-03-18 9:50 ` Vlastimil Babka
2021-03-18 10:22 ` Michal Hocko
2021-03-18 11:10 ` Vlastimil Babka
2021-03-18 11:36 ` Michal Hocko
2021-03-19 9:57 ` Oscar Salvador
2021-03-19 10:14 ` Vlastimil Babka
2021-03-19 10:26 ` Oscar Salvador
2021-03-17 11:12 ` [PATCH v5 3/5] mm: Make alloc_contig_range handle free hugetlb pages Oscar Salvador
2021-03-17 14:22 ` Michal Hocko
2021-03-17 11:12 ` [PATCH v5 4/5] mm: Make alloc_contig_range handle in-use " Oscar Salvador
2021-03-17 14:26 ` Michal Hocko
2021-03-18 8:54 ` Oscar Salvador
2021-03-18 9:29 ` Michal Hocko
2021-03-18 9:59 ` Oscar Salvador
2021-03-18 10:12 ` Michal Hocko [this message]
2021-03-17 11:12 ` [PATCH v5 5/5] mm,page_alloc: Drop unnecessary checks from pfn_range_valid_contig Oscar Salvador
2021-03-17 11:15 ` David Hildenbrand
2021-03-17 14:31 ` Michal Hocko
2021-03-17 14:36 ` David Hildenbrand
2021-03-17 15:03 ` Michal Hocko
2021-03-18 8:44 ` Oscar Salvador
2021-03-18 8:55 ` Michal Hocko
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