Commit 8a78882d authored by Miaohe Lin's avatar Miaohe Lin Committed by Andrew Morton
Browse files

mm/memory-failure: remove obsolete MF_MSG_DIFFERENT_COMPOUND 

The page cannot become compound pages again just after a folio is split as
an extra refcnt is held.  So the MF_MSG_DIFFERENT_COMPOUND case is
obsolete and can be removed to get rid of this false assumption and code
burden.  But add one WARN_ON() here to keep the situation clear.

Link: https://lkml.kernel.org/r/20240708030544.196919-1-linmiaohe@huawei.com


Signed-off-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a5ea5212

include/ras/ras_event.h

+0 −1
Original line number Diff line number Diff line
@@ -356,7 +356,6 @@ TRACE_EVENT(aer_event, 
#define MF_PAGE_TYPE		\

	EM ( MF_MSG_KERNEL, "reserved kernel page" )			\

	EM ( MF_MSG_KERNEL_HIGH_ORDER, "high-order kernel page" )	\

	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" )			\

mm/memory-failure.c

+3 −16
Original line number Diff line number Diff line
@@ -919,7 +919,6 @@ static const char *action_name[] = { 
static const char * const action_page_types[] = {

	[MF_MSG_KERNEL]			= "reserved kernel page",

	[MF_MSG_KERNEL_HIGH_ORDER]	= "high-order kernel page",

	[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",
@@ -2349,22 +2348,10 @@ int memory_failure(unsigned long pfn, int flags) 


	/*

	 * We're only intended to deal with the non-Compound page here.

	 * However, the page could have changed compound pages due to

	 * race window. If this happens, we could try again to hopefully

	 * handle the page next round.

	 * The page cannot become compound pages again as folio has been

	 * splited and extra refcnt is held.

	 */

	if (folio_test_large(folio)) {

		if (retry) {

			ClearPageHWPoison(p);

			folio_unlock(folio);

			folio_put(folio);

			flags &= ~MF_COUNT_INCREASED;

			retry = false;

			goto try_again;

		}

		res = action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED);

		goto unlock_page;

	}

	WARN_ON(folio_test_large(folio));



	/*

	 * We use page flags to determine what action should be taken, but