[PATCH v1 09/12] powerpc/pseries: CMM: Switch to balloon_page_alloc()

David Hildenbrand
2019-10-31T14:30:39Z

balloon_page_alloc() will use GFP_HIGHUSER_MOVABLE in case we have
CONFIG_BALLOON_COMPACTION. This is now possible, as balloon pages are
movable with CONFIG_BALLOON_COMPACTION. Without
CONFIG_BALLOON_COMPACTION, GFP_HIGHUSER is used.

Note that apart from that, balloon_page_alloc() uses the following
flags:
__GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN
And current code used:
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC

GFP_HIGHUSER/GFP_HIGHUSER_MOVABLE include
__GFP_RECLAIM | __GFP_IO | __GFP_FS | __GFP_HARDWALL | __GFP_HIGHMEM

GFP_NOIO is __GFP_RECLAIM.

With CONFIG_BALLOON_COMPACTION, we essentially add:
__GFP_IO | __GFP_FS | __GFP_HARDWALL | __GFP_HIGHMEM | __GFP_MOVABLE

Without CONFIG_BALLOON_COMPACTION, we essentially add:
__GFP_IO | __GFP_FS | __GFP_HARDWALL | __GFP_HIGHMEM

I assume this is fine, as this is what all other balloon compaction
users use. If it turns out to be a problem, we could add
__GFP_MOVABLE manually if we have CONFIG_BALLOON_COMPACTION.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arun KS <arunks@codeaurora.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/powerpc/platforms/pseries/cmm.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index 235fd7fe9df1..a6ec2bbb1f91 100644
--- a/arch/powerpc/platforms/pseries/cmm.c
+++ b/arch/powerpc/platforms/pseries/cmm.c
@@ -147,8 +147,7 @@ static long cmm_alloc_pages(long nr)
break;
}

- page = alloc_page(GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY |
- __GFP_NOMEMALLOC);
+ page = balloon_page_alloc();
if (!page)
break;
rc = plpar_page_set_loaned(page);
--
2.21.0