From: Miaohe Lin <linmiaohe@huawei.com>
To: Jane Chu <jane.chu@oracle.com>
Cc: <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
<akpm@linux-foundation.org>, <nao.horiguchi@gmail.com>,
<osalvador@suse.de>, Matthew Wilcox <willy@infradead.org>,
Sidhartha Kumar <sidhartha.kumar@oracle.com>
Subject: Re: [PATCH] mm/memory-failure: remove shake_page()
Date: Sun, 28 Apr 2024 10:24:46 +0800 [thread overview]
Message-ID: <6048a36d-6bb2-2e74-1d20-228f0486d965@huawei.com> (raw)
In-Reply-To: <d19e1033-285f-474b-af1f-ae4c32e32e21@oracle.com>
On 2024/4/27 4:33, Jane Chu wrote:
> My apology for the gobbled message earlier.
>
> On 4/26/2024 12:52 PM, Jane Chu wrote:
>> On 4/26/2024 12:05 PM, Matthew Wilcox wrote:
>> [..]
>>> That would be unsafe, the safe way would be if we moved page_folio() after
>>>> the call to __get_hw_poison() in get_any_page() and there would still be one
>>>> remaining user of shake_page() that we can't convert. A safe version of this
>>>> patch would result in a removal of one use of PageHuge() and two uses of
>>>> put_page(), would that be worth submitting?
>>>>
>>>> get_any_page()
>>>> if(__get_hwpoison_page())
>>>> folio = page_folio() /* folio_try_get() returned 1, safe */
>>> I think we should convert __get_hwpoison_page() to return either the folio
>>> or an ERR_PTR or NULL. Also, I think we should delete the "cannot catch
>>> tail" part and just loop in __get_hwpoison_page() until we do catch it.
>>> See try_get_folio() in mm/gup.c for inspiration (although you can't use
>>> it exactly because that code knows that the page is mapped into a page
>>> table, so has a refcount).
>>>
>>> But that's just an immediate assessment; you might find a reason that
>>> doesn't work.
>>
> Besides, in a possible hugetlb demote scenario, it seems to me that we should retry
> get_hwpoison_hugetlb_folio() instead of falling thru to folio_try_get().
>
> static int __get_hwpoison_page(struct page *page, unsigned long flags)
> {
> struct folio *folio = page_folio(page);
> int ret = 0;
> bool hugetlb = false;
>
> ret = get_hwpoison_hugetlb_folio(folio, &hugetlb, false);
> if (hugetlb) {
> /* Make sure hugetlb demotion did not happen from under us. */
> if (folio == page_folio(page))
> return ret;
> if (ret > 0) { <===== still hugetlb, don't fall thru, retry
I tend to agree we should retry get_hwpoison_hugetlb_folio() because folio is still hugetlb in this case.
Below folio_try_get() won't do the right things. This is on my TODO list but as you mentioned this, please
feel free to submit the corresponding patch.
Thanks.
.
prev parent reply other threads:[~2024-04-28 2:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-26 17:15 [PATCH] mm/memory-failure: remove shake_page() Sidhartha Kumar
2024-04-26 17:34 ` Matthew Wilcox
2024-04-26 17:57 ` Sidhartha Kumar
2024-04-26 18:27 ` Matthew Wilcox
2024-04-26 18:53 ` Sidhartha Kumar
2024-04-26 19:05 ` Matthew Wilcox
2024-04-26 19:52 ` Jane Chu
2024-04-26 20:33 ` Jane Chu
2024-04-28 2:24 ` Miaohe Lin [this message]
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=6048a36d-6bb2-2e74-1d20-228f0486d965@huawei.com \
--to=linmiaohe@huawei.com \
--cc=akpm@linux-foundation.org \
--cc=jane.chu@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=nao.horiguchi@gmail.com \
--cc=osalvador@suse.de \
--cc=sidhartha.kumar@oracle.com \
--cc=willy@infradead.org \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).