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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-01-15 16:51:21 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-15 17:56:32 -0800 |
| commit | 95ad97554ac81b31139d4fe5ed8757a07087cd90 (patch) | |
| tree | 1943f0cac035d6aab5217ba42df1a8d243c2d270 /lib | |
| parent | 0e6d31a7336f41ef0375f5398c79e54de8e219b6 (diff) | |
| download | lwn-95ad97554ac81b31139d4fe5ed8757a07087cd90.tar.gz lwn-95ad97554ac81b31139d4fe5ed8757a07087cd90.zip | |
page-flags: introduce page flags policies wrt compound pages
This patch adds a third argument to macros which create function
definitions for page flags. This argument defines how page-flags
helpers behave on compound functions.
For now we define four policies:
- PF_ANY: the helper function operates on the page it gets, regardless
if it's non-compound, head or tail.
- PF_HEAD: the helper function operates on the head page of the
compound page if it gets tail page.
- PF_NO_TAIL: only head and non-compond pages are acceptable for this
helper function.
- PF_NO_COMPOUND: only non-compound pages are acceptable for this
helper function.
For now we use policy PF_ANY for all helpers, which matches current
behaviour.
We do not enforce the policy for TESTPAGEFLAG, because we have flags
checked for random pages all over the kernel. Noticeable exception to
this is PageTransHuge() which triggers VM_BUG_ON() for tail page.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.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: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index ee1ac1cc082c..8fbdef1980a5 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -580,6 +580,14 @@ 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 |