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

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
......@@ -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)
......
......@@ -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)
......
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