kexec: export free_huge_page to VMCOREINFO
PG_head_mask was added into VMCOREINFO to filter huge pages in b3acc56bfe1
("kexec: save PG_head_mask in VMCOREINFO"), but makedumpfile still need
another symbol to filter *hugetlbfs* pages.
If a user hope to filter user pages, makedumpfile tries to exclude them by
checking the condition whether the page is anonymous, but hugetlbfs pages
aren't anonymous while they also be user pages.
We know it's possible to detect them in the same way as PageHuge(),
so we need the start address of free_huge_page():
int PageHuge(struct page *page)
{
if (!PageCompound(page))
return 0;
page = compound_head(page);
return get_compound_page_dtor(page) == free_huge_page;
}
For that reason, this patch changes free_huge_page() into public
to export it to VMCOREINFO.
Signed-off-by: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 255cd5c..a23c096 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -80,6 +80,7 @@
bool isolate_huge_page(struct page *page, struct list_head *list);
void putback_active_hugepage(struct page *page);
bool is_hugepage_active(struct page *page);
+void free_huge_page(struct page *page);
#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud);
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 369f41a..23a088f 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -33,6 +33,7 @@
#include <linux/swap.h>
#include <linux/syscore_ops.h>
#include <linux/compiler.h>
+#include <linux/hugetlb.h>
#include <asm/page.h>
#include <asm/uaccess.h>
@@ -1619,6 +1620,7 @@
#endif
VMCOREINFO_NUMBER(PG_head_mask);
VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
+ VMCOREINFO_SYMBOL(free_huge_page);
arch_crash_save_vmcoreinfo();
update_vmcoreinfo_note();
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9221c02..7a0a73d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -856,7 +856,7 @@
return NULL;
}
-static void free_huge_page(struct page *page)
+void free_huge_page(struct page *page)
{
/*
* Can't pass hstate in here because it is called from the