Commit 783657a7 authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds

mm: soft offline: split thp at the beginning of soft_offline_page()

When we try to soft-offline a thp tail page, put_page() is called on the
tail page unthinkingly and VM_BUG_ON is triggered in put_compound_page().

This patch splits thp before going into the main body of soft-offlining.
Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 782fd304
......@@ -1476,9 +1476,17 @@ int soft_offline_page(struct page *page, int flags)
{
int ret;
unsigned long pfn = page_to_pfn(page);
struct page *hpage = compound_trans_head(page);
if (PageHuge(page))
return soft_offline_huge_page(page, flags);
if (PageTransHuge(hpage)) {
if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
pr_info("soft offline: %#lx: failed to split THP\n",
pfn);
return -EBUSY;
}
}
ret = get_any_page(page, pfn, flags);
if (ret < 0)
......
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