[PATCH 1/2] mm: get rid of __alloc_pages_high_priority

From: mhocko
Date: Mon Nov 16 2015 - 08:22:41 EST


From: Michal Hocko <mhocko@xxxxxxxx>

__alloc_pages_high_priority doesn't do anything special other than it
calls get_page_from_freelist and loops around GFP_NOFAIL allocation
until it succeeds. It would be better if the first part was done in
__alloc_pages_slowpath where we modify the zonelist because this would
be easier to read and understand. Opencoding the function into its only
caller allows to simplify it a bit as well.

This patch doesn't introduce any functional changes.

Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
mm/page_alloc.c | 36 +++++++++---------------------------
1 file changed, 9 insertions(+), 27 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8034909faad2..b153fa3d0b9b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2902,28 +2902,6 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
return page;
}

-/*
- * This is called in the allocator slow-path if the allocation request is of
- * sufficient urgency to ignore watermarks and take other desperate measures
- */
-static inline struct page *
-__alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
- const struct alloc_context *ac)
-{
- struct page *page;
-
- do {
- page = get_page_from_freelist(gfp_mask, order,
- ALLOC_NO_WATERMARKS, ac);
-
- if (!page && gfp_mask & __GFP_NOFAIL)
- wait_iff_congested(ac->preferred_zone, BLK_RW_ASYNC,
- HZ/50);
- } while (!page && (gfp_mask & __GFP_NOFAIL));
-
- return page;
-}
-
static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac)
{
struct zoneref *z;
@@ -3068,12 +3046,16 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
* allocations are system rather than user orientated
*/
ac->zonelist = node_zonelist(numa_node_id(), gfp_mask);
+ do {
+ page = get_page_from_freelist(gfp_mask, order,
+ ALLOC_NO_WATERMARKS, ac);
+ if (page)
+ goto got_pg;

- page = __alloc_pages_high_priority(gfp_mask, order, ac);
-
- if (page) {
- goto got_pg;
- }
+ if (gfp_mask & __GFP_NOFAIL)
+ wait_iff_congested(ac->preferred_zone,
+ BLK_RW_ASYNC, HZ/50);
+ } while (gfp_mask & __GFP_NOFAIL);
}

/* Caller is not willing to reclaim, we can't balance anything */
--
2.6.2

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