Commit b8b9488d authored by Jane Chu's avatar Jane Chu Committed by Andrew Morton
Browse files

mm/memory-failure: improve memory failure action_result messages 

Added two explicit MF_MSG messages describing failure in
get_hwpoison_page.  Attemped to document the definition of various action
names, and made a few adjustment to the action_result() calls.

Link: https://lkml.kernel.org/r/20240524215306.2705454-4-jane.chu@oracle.com


Signed-off-by: default avatarJane Chu <jane.chu@oracle.com>
Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
Acked-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 66802526

include/linux/mm.h

+2 −0
Original line number Diff line number Diff line
@@ -4096,6 +4096,7 @@ enum mf_action_page_type { 
	MF_MSG_DIFFERENT_COMPOUND,

	MF_MSG_HUGE,

	MF_MSG_FREE_HUGE,

	MF_MSG_GET_HWPOISON,

	MF_MSG_UNMAP_FAILED,

	MF_MSG_DIRTY_SWAPCACHE,

	MF_MSG_CLEAN_SWAPCACHE,
@@ -4109,6 +4110,7 @@ enum mf_action_page_type { 
	MF_MSG_BUDDY,

	MF_MSG_DAX,

	MF_MSG_UNSPLIT_THP,

	MF_MSG_ALREADY_POISONED,

	MF_MSG_UNKNOWN,

};

include/ras/ras_event.h

+2 −0
Original line number Diff line number Diff line
@@ -360,6 +360,7 @@ TRACE_EVENT(aer_event, 
	EM ( MF_MSG_DIFFERENT_COMPOUND, "different compound page after locking" ) \

	EM ( MF_MSG_HUGE, "huge page" )					\

	EM ( MF_MSG_FREE_HUGE, "free huge page" )			\

	EM ( MF_MSG_GET_HWPOISON, "get hwpoison page" )			\

	EM ( MF_MSG_UNMAP_FAILED, "unmapping failed page" )		\

	EM ( MF_MSG_DIRTY_SWAPCACHE, "dirty swapcache page" )		\

	EM ( MF_MSG_CLEAN_SWAPCACHE, "clean swapcache page" )		\
@@ -373,6 +374,7 @@ TRACE_EVENT(aer_event, 
	EM ( MF_MSG_BUDDY, "free buddy page" )				\

	EM ( MF_MSG_DAX, "dax page" )					\

	EM ( MF_MSG_UNSPLIT_THP, "unsplit thp" )			\

	EM ( MF_MSG_ALREADY_POISONED, "already poisoned" )		\

	EMe ( MF_MSG_UNKNOWN, "unknown page" )



/*

mm/memory-failure.c

+32 −5
Original line number Diff line number Diff line
@@ -879,6 +879,28 @@ static int kill_accessing_process(struct task_struct *p, unsigned long pfn, 
	return ret > 0 ? -EHWPOISON : -EFAULT;

}



/*

 * MF_IGNORED - The m-f() handler marks the page as PG_hwpoisoned'ed.

 * But it could not do more to isolate the page from being accessed again,

 * nor does it kill the process. This is extremely rare and one of the

 * potential causes is that the page state has been changed due to

 * underlying race condition. This is the most severe outcomes.

 *

 * MF_FAILED - The m-f() handler marks the page as PG_hwpoisoned'ed.

 * It should have killed the process, but it can't isolate the page,

 * due to conditions such as extra pin, unmap failure, etc. Accessing

 * the page again may trigger another MCE and the process will be killed

 * by the m-f() handler immediately.

 *

 * MF_DELAYED - The m-f() handler marks the page as PG_hwpoisoned'ed.

 * The page is unmapped, and is removed from the LRU or file mapping.

 * An attempt to access the page again will trigger page fault and the

 * PF handler will kill the process.

 *

 * MF_RECOVERED - The m-f() handler marks the page as PG_hwpoisoned'ed.

 * The page has been completely isolated, that is, unmapped, taken out of

 * the buddy system, or hole-punnched out of the file mapping.

 */

static const char *action_name[] = {

	[MF_IGNORED] = "Ignored",

	[MF_FAILED] = "Failed",
@@ -893,6 +915,7 @@ static const char * const action_page_types[] = { 
	[MF_MSG_DIFFERENT_COMPOUND]	= "different compound page after locking",

	[MF_MSG_HUGE]			= "huge page",

	[MF_MSG_FREE_HUGE]		= "free huge page",

	[MF_MSG_GET_HWPOISON]		= "get hwpoison page",

	[MF_MSG_UNMAP_FAILED]		= "unmapping failed page",

	[MF_MSG_DIRTY_SWAPCACHE]	= "dirty swapcache page",

	[MF_MSG_CLEAN_SWAPCACHE]	= "clean swapcache page",
@@ -906,6 +929,7 @@ static const char * const action_page_types[] = { 
	[MF_MSG_BUDDY]			= "free buddy page",

	[MF_MSG_DAX]			= "dax page",

	[MF_MSG_UNSPLIT_THP]		= "unsplit thp",

	[MF_MSG_ALREADY_POISONED]	= "already poisoned",

	[MF_MSG_UNKNOWN]		= "unknown page",

};
@@ -1013,12 +1037,13 @@ static int me_kernel(struct page_state *ps, struct page *p) 


/*

 * Page in unknown state. Do nothing.

 * This is a catch-all in case we fail to make sense of the page state.

 */

static int me_unknown(struct page_state *ps, struct page *p)

{

	pr_err("%#lx: Unknown page state\n", page_to_pfn(p));

	unlock_page(p);

	return MF_FAILED;

	return MF_IGNORED;

}



/*
@@ -2055,6 +2080,7 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb 
		if (flags & MF_ACTION_REQUIRED) {

			folio = page_folio(p);

			res = kill_accessing_process(current, folio_pfn(folio), flags);

			action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);

		}

		return res;

	} else if (res == -EBUSY) {
@@ -2062,7 +2088,7 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb 
			flags |= MF_NO_RETRY;

			goto retry;

		}

		return action_result(pfn, MF_MSG_UNKNOWN, MF_IGNORED);

		return action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED);

	}



	folio = page_folio(p);
@@ -2097,7 +2123,7 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb 


	if (!hwpoison_user_mappings(folio, p, pfn, flags)) {

		folio_unlock(folio);

		return action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);

		return action_result(pfn, MF_MSG_UNMAP_FAILED, MF_FAILED);

	}



	return identify_page_state(pfn, p, page_flags);
@@ -2231,6 +2257,7 @@ int memory_failure(unsigned long pfn, int flags) 
			res = kill_accessing_process(current, pfn, flags);

		if (flags & MF_COUNT_INCREASED)

			put_page(p);

		action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);

		goto unlock_mutex;

	}
@@ -2267,7 +2294,7 @@ int memory_failure(unsigned long pfn, int flags) 
			}

			goto unlock_mutex;

		} else if (res < 0) {

			res = action_result(pfn, MF_MSG_UNKNOWN, MF_IGNORED);

			res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED);

			goto unlock_mutex;

		}

	}
@@ -2363,7 +2390,7 @@ int memory_failure(unsigned long pfn, int flags) 
	 * Abort on fail: __filemap_remove_folio() assumes unmapped page.

	 */

	if (!hwpoison_user_mappings(folio, p, pfn, flags)) {

		res = action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);

		res = action_result(pfn, MF_MSG_UNMAP_FAILED, MF_FAILED);

		goto unlock_page;

	}