On Mon, 12 Dec 2011 15:29:07 +0100, Mel Gorman <mel@xxxxxxxxx> wrote:
On Fri, Nov 18, 2011 at 05:43:11PM +0100, Marek Szyprowski wrote:
From: Michal Nazarewicz <mina86@xxxxxxxxxx>
This commit exports some of the functions from compaction.c file
outside of it adding their declaration into internal.h header
file so that other mm related code can use them.
This forced compaction.c to always be compiled (as opposed to being
compiled only if CONFIG_COMPACTION is defined) but as to avoid
introducing code that user did not ask for, part of the compaction.c
is now wrapped in on #ifdef.
Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
mm/Makefile | 3 +-
mm/compaction.c | 112 +++++++++++++++++++++++--------------------------------
mm/internal.h | 35 +++++++++++++++++
3 files changed, 83 insertions(+), 67 deletions(-)
diff --git a/mm/Makefile b/mm/Makefile
index 50ec00e..24ed801 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -13,7 +13,7 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \
readahead.o swap.o truncate.o vmscan.o shmem.o \
prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
page_isolation.o mm_init.o mmu_context.o percpu.o \
- $(mmu-y)
+ $(mmu-y) compaction.o
That should be
compaction.o $(mmu-y)
for consistency.
Overall, this patch implies that CMA is always compiled in.
Not really. But yes, it produces some bloat when neither CMA nor
compaction are compiled. I assume that linker will be able to deal
with that (since the functions are not EXPORT_SYMBOL'ed).
Note also that the was majority of compaction.c is #ifdef'd though
so only a handful of functions are compiled.
Why not just make CMA depend on COMPACTION to keep things simplier?
I could imagine that someone would want to have CMA but not compaction,
hence I decided to give that choice.
For example, if you enable CMA and do not enable COMPACTION, you
lose things like the vmstat counters that can aid debugging. In
fact, as parts of compaction.c are using defines like COMPACTBLOCKS,
I'm not even sure compaction.c can compile without CONFIG_COMPACTION
because of the vmstat stuff.
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +----<email/xmpp: mpn@xxxxxxxxxx>--------------ooO--(_)--Ooo--
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