lkml.org 
[lkml]   [2024]   [May]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 5/5] mm/memory-failure: send SIGBUS in the event of thp split fail
Date
When handle hwpoison in a RDMA longterm pinned thp page,
try_to_split_thp_page() will fail. And at this point, there is
little else the kernel could do except sending a SIGBUS to
the user process, thus give it a chance to recover.

Signed-off-by: Jane Chu <jane.chu@oracle.com>
---
mm/memory-failure.c | 31 ++++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 2fa884d8b5a3..15bb1c0c42e8 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1697,7 +1697,7 @@ static int identify_page_state(unsigned long pfn, struct page *p,
return page_action(ps, p, pfn);
}

-static int try_to_split_thp_page(struct page *page)
+static int try_to_split_thp_page(struct page *page, bool release)
{
int ret;

@@ -1705,7 +1705,7 @@ static int try_to_split_thp_page(struct page *page)
ret = split_huge_page(page);
unlock_page(page);

- if (unlikely(ret))
+ if (ret && release)
put_page(page);

return ret;
@@ -2177,6 +2177,24 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
return rc;
}

+/*
+ * The calling condition is as such: thp split failed, page might have
+ * been RDMA pinned, not much can be done for recovery.
+ * But a SIGBUS should be delivered with vaddr provided so that the user
+ * application has a chance to recover. Also, application processes'
+ * election for MCE early killed will be honored.
+ */
+static int kill_procs_now(struct page *p, unsigned long pfn, int flags,
+ struct folio *folio)
+{
+ LIST_HEAD(tokill);
+
+ collect_procs(folio, p, &tokill, flags & MF_ACTION_REQUIRED);
+ kill_procs(&tokill, true, pfn, flags);
+
+ return -EHWPOISON;
+}
+
/**
* memory_failure - Handle memory failure of a page.
* @pfn: Page Number of the corrupted page
@@ -2313,8 +2331,11 @@ int memory_failure(unsigned long pfn, int flags)
* page is a valid handlable page.
*/
folio_set_has_hwpoisoned(folio);
- if (try_to_split_thp_page(p) < 0) {
- res = action_result(pfn, MF_MSG_UNSPLIT_THP, MF_IGNORED);
+ if (try_to_split_thp_page(p, false) < 0) {
+ pr_err("%#lx: thp split failed\n", pfn);
+ res = kill_procs_now(p, pfn, flags, folio);
+ put_page(p);
+ res = action_result(pfn, MF_MSG_UNSPLIT_THP, MF_FAILED);
goto unlock_mutex;
}
VM_BUG_ON_PAGE(!page_count(p), p);
@@ -2688,7 +2709,7 @@ static int soft_offline_in_use_page(struct page *page)
};

if (!huge && folio_test_large(folio)) {
- if (try_to_split_thp_page(page)) {
+ if (try_to_split_thp_page(page, true)) {
pr_info("soft offline: %#lx: thp split failed\n", pfn);
return -EBUSY;
}
--
2.39.3

\
 
 \ /
  Last update: 2024-05-27 18:23    [W:0.538 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site