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Groups > linux.kernel > #1237943 > unrolled thread
| Started by | "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> |
|---|---|
| First post | 2015-10-02 07:50 +0200 |
| Last post | 2015-10-02 07:50 +0200 |
| Articles | 3 — 1 participant |
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[PATCH 0/3] page-flags updates "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-10-02 07:50 +0200
[PATCH 2/3] page-flags: add documentation for policies "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-10-02 07:50 +0200
[PATCH 3/3] page-flags: hide PF_* validation check under separate config option "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2015-10-02 07:50 +0200
| From | "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> |
|---|---|
| Date | 2015-10-02 07:50 +0200 |
| Subject | [PATCH 0/3] page-flags updates |
| Message-ID | <qf1od-2Go-3@gated-at.bofh.it> |
Few updates based on Andrew's feedback. Kirill A. Shutemov (3): page-flags: do not corrupt caller 'page' in PF_NO_TAIL page-flags: add documentation for policies page-flags: hide PF_* validation check under separate config option include/linux/mmdebug.h | 6 ++++++ include/linux/page-flags.h | 30 +++++++++++++++++++++--------- lib/Kconfig.debug | 8 ++++++++ 3 files changed, 35 insertions(+), 9 deletions(-) -- 2.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> |
|---|---|
| Date | 2015-10-02 07:50 +0200 |
| Subject | [PATCH 2/3] page-flags: add documentation for policies |
| Message-ID | <qf1oe-2Go-7@gated-at.bofh.it> |
| In reply to | #1237943 |
The patch adds description for page flags policies.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/linux/page-flags.h | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 465ca42af633..19e4129f00e5 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -133,7 +133,23 @@ enum pageflags {
#ifndef __GENERATING_BOUNDS_H
-/* Page flags policies wrt compound pages */
+/*
+ * Page flags policies wrt compound pages
+ *
+ * PF_ANY:
+ * the page flag is relevant for small, head and tail pages.
+ *
+ * PF_HEAD:
+ * for compound page all operations related to the page flag applied to
+ * head page.
+ *
+ * PF_NO_TAIL:
+ * modifications of the page flag must be done on small or head pages,
+ * checks can be done on tail pages too.
+ *
+ * PF_NO_COMPOUND:
+ * the page flag is not relevant for compound pages.
+ */
#define PF_ANY(page, enforce) page
#define PF_HEAD(page, enforce) compound_head(page)
#define PF_NO_TAIL(page, enforce) ({ \
--
2.5.1
--
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| From | "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> |
|---|---|
| Date | 2015-10-02 07:50 +0200 |
| Subject | [PATCH 3/3] page-flags: hide PF_* validation check under separate config option |
| Message-ID | <qf1oe-2Go-9@gated-at.bofh.it> |
| In reply to | #1237943 |
VM_BUG_ONs in PF_NO_TAIL() and PF_NO_COMPOUND() add 4+ KiB to
mm/build-in.o for DEBUG_VM kernel.
Let's hide them under new config option -- CONFIG_DEBUG_VM_PGFLAGS.
With the option enabled VM_BUG_ON_PGFLAGS() is equal to VM_BUG_ON_PAGE.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/linux/mmdebug.h | 6 ++++++
include/linux/page-flags.h | 8 +++-----
lib/Kconfig.debug | 8 ++++++++
3 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 877ef226f90f..c447d8055e50 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -55,4 +55,10 @@ void dump_mm(const struct mm_struct *mm);
#define VIRTUAL_BUG_ON(cond) do { } while (0)
#endif
+#ifdef CONFIG_DEBUG_VM_PGFLAGS
+#define VM_BUG_ON_PGFLAGS(cond, page) VM_BUG_ON_PAGE(cond, page)
+#else
+#define VM_BUG_ON_PGFLAGS(cond, page) BUILD_BUG_ON_INVALID(cond)
+#endif
+
#endif
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 19e4129f00e5..8d6e4e9a98af 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -153,12 +153,10 @@ enum pageflags {
#define PF_ANY(page, enforce) page
#define PF_HEAD(page, enforce) compound_head(page)
#define PF_NO_TAIL(page, enforce) ({ \
- if (enforce) \
- VM_BUG_ON_PAGE(PageTail(page), page); \
+ VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
compound_head(page);})
-#define PF_NO_COMPOUND(page, enforce) ({ \
- if (enforce) \
- VM_BUG_ON_PAGE(PageCompound(page), page); \
+#define PF_NO_COMPOUND(page, enforce) ({ \
+ VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
page;})
/*
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e2894b23efb6..0d12bfa429de 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -570,6 +570,14 @@ config DEBUG_VM_RB
If unsure, say N.
+config DEBUG_VM_PGFLAGS
+ bool "Debug page-flags operations"
+ depends on DEBUG_VM
+ help
+ Enables extra validation on page flags operations.
+
+ If unsure, say N.
+
config DEBUG_VIRTUAL
bool "Debug VM translations"
depends on DEBUG_KERNEL && X86
--
2.5.1
--
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