From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
xishi.qiuxishi@alibaba-inc.com,
Laurent Dufour <ldufour@linux.vnet.ibm.com>
Subject: Re: [RFC][PATCH v1 04/11] mm: madvise: call soft_offline_page() without MF_COUNT_INCREASED
Date: Fri, 9 Nov 2018 16:16:55 +0530 [thread overview]
Message-ID: <21e5b9ca-ad72-b0d5-3397-4b65831b236b@arm.com> (raw)
In-Reply-To: <1541746035-13408-5-git-send-email-n-horiguchi@ah.jp.nec.com>
On 11/09/2018 12:17 PM, Naoya Horiguchi wrote:
> Currently madvise_inject_error() pins the target page when calling
> memory error handler, but it's not good because the refcount is just
> an artifact of error injector and mock nothing about hw error itself.
> IOW, pinning the error page is part of error handler's task, so
> let's stop doing it.
Did not get that. Could you please kindly explain how an incremented
ref count through get_user_pages_fast() was a mocking the HW error
previously ? Though I might be missing the some context here.
>
> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> ---
> mm/madvise.c | 25 +++++++++++--------------
> 1 file changed, 11 insertions(+), 14 deletions(-)
>
> diff --git v4.19-mmotm-2018-10-30-16-08/mm/madvise.c v4.19-mmotm-2018-10-30-16-08_patched/mm/madvise.c
> index 6cb1ca9..9fa0225 100644
> --- v4.19-mmotm-2018-10-30-16-08/mm/madvise.c
> +++ v4.19-mmotm-2018-10-30-16-08_patched/mm/madvise.c
> @@ -637,6 +637,16 @@ static int madvise_inject_error(int behavior,
> ret = get_user_pages_fast(start, 1, 0, &page);
> if (ret != 1)
> return ret;
> + /*
> + * The get_user_pages_fast() is just to get the pfn of the
> + * given address, and the refcount has nothing to do with
> + * what we try to test, so it should be released immediately.
> + * This is racy but it's intended because the real hardware
> + * errors could happen at any moment and memory error handlers
> + * must properly handle the race.
> + */
> + put_page(page);
> +
> pfn = page_to_pfn(page);
>
> /*
> @@ -646,16 +656,11 @@ static int madvise_inject_error(int behavior,
> */
> order = compound_order(compound_head(page));
>
> - if (PageHWPoison(page)) {
> - put_page(page);
> - continue;
> - }
> -
> if (behavior == MADV_SOFT_OFFLINE) {
> pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
> pfn, start);
>
> - ret = soft_offline_page(page, MF_COUNT_INCREASED);
> + ret = soft_offline_page(page, 0);
Probably something defined as a new "ignored" in the memory faults flag
enumeration instead of passing '0' directly.
next prev parent reply other threads:[~2018-11-09 10:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-09 6:47 [PATCH RFC v1 00/11] hwpoison improvement part 1 Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 01/11] mm: hwpoison: cleanup unused PageHuge() check Naoya Horiguchi
2018-11-09 9:52 ` Anshuman Khandual
2018-11-09 6:47 ` [RFC][PATCH v1 02/11] mm: soft-offline: add missing error check of set_hwpoison_free_buddy_page() Naoya Horiguchi
2018-11-09 10:20 ` Anshuman Khandual
2018-11-13 0:16 ` Naoya Horiguchi
2018-11-14 8:53 ` Anshuman Khandual
2018-11-09 6:47 ` [RFC][PATCH v1 03/11] mm: move definition of num_poisoned_pages_inc/dec to include/linux/mm.h Naoya Horiguchi
2018-11-09 10:28 ` Anshuman Khandual
2018-11-13 0:17 ` Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 04/11] mm: madvise: call soft_offline_page() without MF_COUNT_INCREASED Naoya Horiguchi
2018-11-09 10:46 ` Anshuman Khandual [this message]
2018-11-13 0:18 ` Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 05/11] mm: hwpoison-inject: don't pin for hwpoison_filter() Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 06/11] mm: hwpoison: remove MF_COUNT_INCREASED Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 07/11] mm: remove flag argument from soft offline functions Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 08/11] mm: soft-offline: isolate error pages from buddy freelist Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 09/11] mm: hwpoison: apply buddy page handling code to hard-offline Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 10/11] mm: clear PageHWPoison in memory hotremove Naoya Horiguchi
2018-11-13 1:32 ` Naoya Horiguchi
2018-11-09 6:47 ` [RFC][PATCH v1 11/11] mm: hwpoison: introduce clear_hwpoison_free_buddy_page() Naoya Horiguchi
2018-11-09 11:33 ` Anshuman Khandual
2018-11-13 0:19 ` Naoya Horiguchi
2018-11-14 8:23 ` Anshuman Khandual
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=21e5b9ca-ad72-b0d5-3397-4b65831b236b@arm.com \
--to=anshuman.khandual@arm.com \
--cc=akpm@linux-foundation.org \
--cc=ldufour@linux.vnet.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=mike.kravetz@oracle.com \
--cc=n-horiguchi@ah.jp.nec.com \
--cc=xishi.qiuxishi@alibaba-inc.com \
/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).