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authorPetr Tesarik <ptesarik@suse.cz>2014-06-23 13:22:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-23 16:47:43 -0700
commitb3acc56bfe1287c6b666e80edc70b89eea2a1a80 (patch)
tree2ee8421399cda3bb043396d7f70aa9a2d86c9855 /include
parent8d056c48e486249e6487910b83e0f3be7c14acf7 (diff)
kexec: save PG_head_mask in VMCOREINFO
To allow filtering of huge pages, makedumpfile must be able to identify them in the dump. This can be done by checking the appropriate page flag, so communicate its value to makedumpfile through the VMCOREINFO interface. There's only one small catch. Depending on how many page flags are available on a given architecture, this bit can be called PG_head or PG_compound. I sent a similar patch back in 2012, but Eric Biederman did not like using an #ifdef. So, this time I'm adding a common symbol (PG_head_mask) instead. See https://lkml.org/lkml/2012/11/28/91 for the previous version. Signed-off-by: Petr Tesarik <ptesarik@suse.cz> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Shaohua Li <shli@kernel.org> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/page-flags.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 3c545b48aeab..8304959ad336 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -360,6 +360,9 @@ static inline void ClearPageCompound(struct page *page)
ClearPageHead(page);
}
#endif
+
+#define PG_head_mask ((1L << PG_head))
+
#else
/*
* Reduce page flag use as much as possible by overlapping

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