From: Jane Chu <jane.chu@oracle.com>
To: Matthew Wilcox <willy@infradead.org>,
Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, linmiaohe@huawei.com,
nao.horiguchi@gmail.com, osalvador@suse.de
Subject: Re: [PATCH] mm/memory-failure: remove shake_page()
Date: Fri, 26 Apr 2024 13:33:27 -0700 [thread overview]
Message-ID: <d19e1033-285f-474b-af1f-ae4c32e32e21@oracle.com> (raw)
In-Reply-To: <47614f5d-0942-4b2c-a51a-451f6bc9c802@oracle.com>
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
folio_put(folio);
folio = page_folio(page);
}
}
thanks!
-jane
next prev parent reply other threads:[~2024-04-26 20:33 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 [this message]
2024-04-28 2:24 ` Miaohe Lin
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=d19e1033-285f-474b-af1f-ae4c32e32e21@oracle.com \
--to=jane.chu@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=linmiaohe@huawei.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).