From: Michal Hocko <mhocko@suse.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
David Hildenbrand <david@redhat.com>,
Muchun Song <songmuchun@bytedance.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 3/7] mm,hugetlb: Clear HPageFreed outside of the lock
Date: Wed, 14 Apr 2021 08:04:21 +0200 [thread overview]
Message-ID: <YHaF5efHcJJ71UP9@dhcp22.suse.cz> (raw)
In-Reply-To: <b8f36340-df56-1180-2a14-7b20cc1a0cda@oracle.com>
On Tue 13-04-21 14:19:03, Mike Kravetz wrote:
> On 4/13/21 6:23 AM, Michal Hocko wrote:
> > On Tue 13-04-21 12:47:43, Oscar Salvador wrote:
[...]
> > Or do we need it for giga pages which are not allocated by the page
> > allocator? If yes then moving it to prep_compound_gigantic_page would be
> > better.
>
> I am pretty sure dynamically allocated giga pages have page->Private
> cleared as well. It is not obvious, but the alloc_contig_range code
> used to put together giga pages will end up calling isolate_freepages_range
> that will call split_map_pages and then post_alloc_hook for each MAX_ORDER
> block.
Thanks for saving me from crawling that code.
> As mentioned, this is not obvious and I would hate to rely on this
> behavior not changing.
Thinking about it some more, having some (page granularity) allocator
not clearing page private would be a serious problem for anybody relying
on its state. So I am not sure this can change.
> > So should we just drop it here?
>
> The only place where page->private may not be initialized is when we do
> allocations at boot time from memblock. In this case, we will add the
> pages to the free list via put_page/free_huge_page so the appropriate
> flags will be cleared before anyone notices.
Pages allocated by the bootmem should be pre initialized from the boot,
no?
> I'm wondering if we should just do a set_page_private(page, 0) here in
> prep_new_huge_page since we now use that field for flags. Or, is that
> overkill?
I would rather not duplicate the work done by underlying allocators. I
do not think other users of the allocator want to do the same so why
should hugetlb be any different.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-04-14 6:04 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 10:47 [PATCH v7 0/7] Make alloc_contig_range handle Hugetlb pages Oscar Salvador
2021-04-13 10:47 ` [PATCH v7 1/7] mm,page_alloc: Bail out earlier on -ENOMEM in alloc_contig_migrate_range Oscar Salvador
2021-04-13 17:00 ` Mike Kravetz
2021-04-13 10:47 ` [PATCH v7 2/7] mm,compaction: Let isolate_migratepages_{range,block} return error codes Oscar Salvador
2021-04-13 17:52 ` Mike Kravetz
2021-04-14 11:54 ` David Hildenbrand
2021-04-15 8:42 ` Oscar Salvador
2021-04-13 10:47 ` [PATCH v7 3/7] mm,hugetlb: Clear HPageFreed outside of the lock Oscar Salvador
2021-04-13 13:23 ` Michal Hocko
2021-04-13 21:19 ` Mike Kravetz
2021-04-14 6:04 ` Michal Hocko [this message]
2021-04-14 7:41 ` Oscar Salvador
2021-04-14 8:28 ` Michal Hocko
2021-04-14 10:01 ` Oscar Salvador
2021-04-14 10:03 ` Oscar Salvador
2021-04-14 10:32 ` Michal Hocko
2021-04-14 10:49 ` Oscar Salvador
2021-04-14 11:09 ` Michal Hocko
2021-04-14 12:02 ` David Hildenbrand
2021-04-14 16:45 ` Mike Kravetz
2021-04-13 10:47 ` [PATCH v7 4/7] mm,hugetlb: Split prep_new_huge_page functionality Oscar Salvador
2021-04-13 13:24 ` Michal Hocko
2021-04-13 13:26 ` Michal Hocko
2021-04-13 21:33 ` Mike Kravetz
2021-04-14 4:59 ` Oscar Salvador
2021-04-14 12:15 ` David Hildenbrand
2021-04-14 17:03 ` Mike Kravetz
2021-04-13 10:47 ` [PATCH v7 5/7] mm: Make alloc_contig_range handle free hugetlb pages Oscar Salvador
2021-04-13 13:40 ` Michal Hocko
2021-04-15 8:29 ` Oscar Salvador
2021-04-13 22:29 ` Mike Kravetz
2021-04-14 4:54 ` Oscar Salvador
2021-04-14 12:26 ` David Hildenbrand
2021-04-15 8:28 ` Oscar Salvador
2021-04-13 10:47 ` [PATCH v7 6/7] mm: Make alloc_contig_range handle in-use " Oscar Salvador
2021-04-13 22:48 ` Mike Kravetz
2021-04-14 4:52 ` Oscar Salvador
2021-04-14 17:07 ` Mike Kravetz
2021-04-13 10:47 ` [PATCH v7 7/7] mm,page_alloc: Drop unnecessary checks from pfn_range_valid_contig Oscar Salvador
2021-04-13 22:53 ` Mike Kravetz
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