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Commit 4d2fa965 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

thp, mm: split_huge_page(): caller need to lock page 



We're going to use migration entries instead of compound_lock() to
stabilize page refcounts.  Setup and remove migration entries require
page to be locked.

Some of split_huge_page() callers already have the page locked.  Let's
require everybody to lock the page before calling split_huge_page().

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ba988280

mm/memory-failure.c

+7 −1
Original line number Diff line number Diff line
@@ -1149,7 +1149,9 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
	}



	if (!PageHuge(p) && PageTransHuge(hpage)) {

		lock_page(hpage);

		if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {

			unlock_page(hpage);

			if (!PageAnon(hpage))

				pr_err("MCE: %#lx: non anonymous thp\n", pfn);

			else
@@ -1159,6 +1161,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags) 
			put_hwpoison_page(p);

			return -EBUSY;

		}

		unlock_page(hpage);

		VM_BUG_ON_PAGE(!page_count(p), p);

		hpage = compound_head(p);

	}
@@ -1751,7 +1754,10 @@ int soft_offline_page(struct page *page, int flags) 
		return -EBUSY;

	}

	if (!PageHuge(page) && PageTransHuge(hpage)) {

		if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {

		lock_page(page);

		ret = split_huge_page(hpage);

		unlock_page(page);

		if (unlikely(ret)) {

			pr_info("soft offline: %#lx: failed to split THP\n",

				pfn);

			if (flags & MF_COUNT_INCREASED)

mm/migrate.c

+6 −2
Original line number Diff line number Diff line
@@ -943,9 +943,13 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page, 
		goto out;

	}



	if (unlikely(PageTransHuge(page)))

		if (unlikely(split_huge_page(page)))

	if (unlikely(PageTransHuge(page))) {

		lock_page(page);

		rc = split_huge_page(page);

		unlock_page(page);

		if (rc)

			goto out;

	}



	rc = __unmap_and_move(page, newpage, force, mode);

	if (rc == MIGRATEPAGE_SUCCESS)