From: nao.horiguchi@gmail.com
To: linux-mm@kvack.org
Cc: mhocko@kernel.org, akpm@linux-foundation.org,
mike.kravetz@oracle.com, osalvador@suse.de, tony.luck@intel.com,
david@redhat.com, aneesh.kumar@linux.vnet.ibm.com,
zeil@yandex-team.ru, cai@lca.pw, naoya.horiguchi@nec.com,
linux-kernel@vger.kernel.org
Subject: [PATCH v5 03/16] mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED
Date: Fri, 31 Jul 2020 12:20:59 +0000 [thread overview]
Message-ID: <20200731122112.11263-4-nao.horiguchi@gmail.com> (raw)
In-Reply-To: <20200731122112.11263-1-nao.horiguchi@gmail.com>
From: Naoya Horiguchi <naoya.horiguchi@nec.com>
The call to get_user_pages_fast is only to get the pointer to a struct
page of a given address, pinning it is memory-poisoning handler's job,
so drop the refcount grabbed by get_user_pages_fast().
Note that the target page is still pinned after this put_page() because
the current process should have refcount from mapping.
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
---
mm/madvise.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git v5.8-rc7-mmotm-2020-07-27-18-18/mm/madvise.c v5.8-rc7-mmotm-2020-07-27-18-18_patched/mm/madvise.c
index a16dba21cdf6..1fe89a5b8d33 100644
--- v5.8-rc7-mmotm-2020-07-27-18-18/mm/madvise.c
+++ v5.8-rc7-mmotm-2020-07-27-18-18_patched/mm/madvise.c
@@ -910,16 +910,24 @@ static int madvise_inject_error(int behavior,
*/
size = page_size(compound_head(page));
- if (PageHWPoison(page)) {
- put_page(page);
+ /*
+ * 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);
+
+ if (PageHWPoison(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(pfn, MF_COUNT_INCREASED);
+ ret = soft_offline_page(pfn, 0);
if (ret)
return ret;
continue;
@@ -927,14 +935,6 @@ static int madvise_inject_error(int behavior,
pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
pfn, start);
-
- /*
- * Drop the page reference taken by get_user_pages_fast(). In
- * the absence of MF_COUNT_INCREASED the memory_failure()
- * routine is responsible for pinning the page to prevent it
- * from being released back to the page allocator.
- */
- put_page(page);
ret = memory_failure(pfn, 0);
if (ret)
return ret;
--
2.17.1
next prev parent reply other threads:[~2020-07-31 12:21 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 12:20 [PATCH v5 00/16] HWPOISON: soft offline rework nao.horiguchi
2020-07-31 12:20 ` [PATCH v5 01/16] mm,hwpoison: cleanup unused PageHuge() check nao.horiguchi
2020-07-31 12:20 ` [PATCH v5 02/16] mm, hwpoison: remove recalculating hpage nao.horiguchi
2020-07-31 12:20 ` nao.horiguchi [this message]
2020-07-31 12:21 ` [PATCH v5 04/16] mm,madvise: Refactor madvise_inject_error nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 05/16] mm,hwpoison-inject: don't pin for hwpoison_filter nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 06/16] mm,hwpoison: Un-export get_hwpoison_page and make it static nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 07/16] mm,hwpoison: Kill put_hwpoison_page nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 08/16] mm,hwpoison: remove MF_COUNT_INCREASED nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 09/16] mm,hwpoison: remove flag argument from soft offline functions nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 10/16] mm,hwpoison: Unify THP handling for hard and soft offline nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 11/16] mm,hwpoison: Rework soft offline for free pages nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 12/16] mm,hwpoison: Rework soft offline for in-use pages nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 13/16] mm,hwpoison: Refactor soft_offline_huge_page and __soft_offline_page nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 14/16] mm,hwpoison: Return 0 if the page is already poisoned in soft-offline nao.horiguchi
2020-07-31 12:21 ` [PATCH v5 15/16] mm,hwpoison: introduce MF_MSG_UNSPLIT_THP nao.horiguchi
[not found] ` <20200803123954.GA4631@lca.pw>
2020-08-03 13:36 ` [PATCH v5 00/16] HWPOISON: soft offline rework HORIGUCHI NAOYA(堀口 直也)
[not found] ` <20200803151907.GA8894@lca.pw>
2020-08-05 20:43 ` HORIGUCHI NAOYA(堀口 直也)
[not found] ` <20200803190709.GB8894@lca.pw>
2020-08-04 1:16 ` HORIGUCHI NAOYA(堀口 直也)
2020-08-04 1:49 ` Qian Cai
2020-08-04 8:13 ` osalvador
2020-08-05 20:44 ` HORIGUCHI NAOYA(堀口 直也)
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=20200731122112.11263-4-nao.horiguchi@gmail.com \
--to=nao.horiguchi@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=aneesh.kumar@linux.vnet.ibm.com \
--cc=cai@lca.pw \
--cc=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=mike.kravetz@oracle.com \
--cc=naoya.horiguchi@nec.com \
--cc=osalvador@suse.de \
--cc=tony.luck@intel.com \
--cc=zeil@yandex-team.ru \
/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).