From: Oscar Salvador <osalvador@suse.de>
To: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
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 12:01:47 +0200 [thread overview]
Message-ID: <20210414100147.GD20886@linux> (raw)
In-Reply-To: <YHansW/OnNT6/i9d@dhcp22.suse.cz>
On Wed, Apr 14, 2021 at 10:28:33AM +0200, Michal Hocko wrote:
> You are right it doesn't do it there. But all struct pages, even those
> that are allocated by the bootmem allocator should initialize its struct
> pages. They would be poisoned otherwise, right? I would have to look at
> the exact code path but IIRC this should be around the time bootmem
> allocator state transitions to the page allocator.
Ok, you are right.
struct pages are initialized a bit earlier through:
start_kernel
setup_arch
paging_init
zone_sizes_init
free_area_init
free_area_init_node
free_area_init_core
memmap_init_zone
memmap_init_range
__init_single_page
While the allocation of bootmem hugetlb happens
start_kernel
parse_args
...
hugepages_setup
...
hugetlb_hstate_alloc_pages
__alloc_bootmem_huge_page
which is after the setup_arch() call.
So by the time we get the page from __alloc_bootmem_huge_page(), fields are
zeroed.
I thought we might get in trouble because memblock_alloc_try_nid_raw() calls
page_init_poison() which poisons the chunk with 0xff,e.g:
[ 1.955471] boot: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
[ 1.955476] boot: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
but it seems that does not the memmap struct page.
I checked, and when we get there in __alloc_bootmem_huge_page, page->private is
still zeroed, so I guess it should be safe to assume that we do not really need
to clear the flag in __prep_new_huge_page() routine?
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-04-14 10:02 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
2021-04-14 7:41 ` Oscar Salvador
2021-04-14 8:28 ` Michal Hocko
2021-04-14 10:01 ` Oscar Salvador [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210414100147.GD20886@linux \
--to=osalvador@suse.de \
--cc=akpm@linux-foundation.org \
--cc=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=mike.kravetz@oracle.com \
--cc=songmuchun@bytedance.com \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).