[PATCH v2 02/13] mm/page_alloc: some renames to clarify alloc_flags scopes

[Brendan Jackman <jackmanb@google.com>]

It's pretty confusing that:

- The slowpath and fastpath have a totally distinct set of alloc_flags.

- gfp_to_alloc_flags() sounds generic but it only influences the
  slowpath.

- prepare_alloc_pages() is generic in that it sets up the
  alloc_context, but the alloc_flags it generates are only used for the
  fastpath.

Rename some variables to highlight which alloc_flags are
fastpath-specific. Rename gfp_to_alloc_flags() to highlight that it's
slowpath-specific.

gfp_to_alloc_flags_cma()'s current name is actually fine, but rename it
anyway, just for consistency.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
 mm/page_alloc.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6c4eb6908bd95..bc05d75a41627 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3771,8 +3771,8 @@ alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
 }
 
 /* Must be called after current_gfp_context() which can change gfp_mask */
-static inline unsigned int gfp_to_alloc_flags_cma(gfp_t gfp_mask,
-						  unsigned int alloc_flags)
+static inline unsigned int cma_alloc_flags(gfp_t gfp_mask,
+					   unsigned int alloc_flags)
 {
 #ifdef CONFIG_CMA
 	if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)
@@ -4471,7 +4471,7 @@ static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
 }
 
 static inline unsigned int
-gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order)
+slowpath_alloc_flags(gfp_t gfp_mask, unsigned int order)
 {
 	unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
 
@@ -4508,7 +4508,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order)
 	} else if (unlikely(rt_or_dl_task(current)) && in_task())
 		alloc_flags |= ALLOC_MIN_RESERVE;
 
-	alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags);
+	alloc_flags = cma_alloc_flags(gfp_mask, alloc_flags);
 
 	if (defrag_mode)
 		alloc_flags |= ALLOC_NOFRAGMENT;
@@ -4774,7 +4774,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 	 * kswapd needs to be woken up, and to avoid the cost of setting up
 	 * alloc_flags precisely. So we do that now.
 	 */
-	alloc_flags = gfp_to_alloc_flags(gfp_mask, order);
+	alloc_flags = slowpath_alloc_flags(gfp_mask, order);
 
 	/*
 	 * We need to recalculate the starting point for the zonelist iterator
@@ -4815,7 +4815,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 
 	reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
 	if (reserve_flags)
-		alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) |
+		alloc_flags = cma_alloc_flags(gfp_mask, reserve_flags) |
 					  (alloc_flags & ALLOC_KSWAPD);
 
 	/*
@@ -5017,7 +5017,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
 		int preferred_nid, nodemask_t *nodemask,
 		struct alloc_context *ac, gfp_t *alloc_gfp,
-		unsigned int *alloc_flags)
+		unsigned int *fastpath_alloc_flags)
 {
 	ac->highest_zoneidx = gfp_zone(gfp_mask);
 	ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
@@ -5033,7 +5033,7 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
 		if (in_task() && !ac->nodemask)
 			ac->nodemask = &cpuset_current_mems_allowed;
 		else
-			*alloc_flags |= ALLOC_CPUSET;
+			*fastpath_alloc_flags |= ALLOC_CPUSET;
 	}
 
 	might_alloc(gfp_mask);
@@ -5042,11 +5042,11 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
 	 * Don't invoke should_fail logic, since it may call
 	 * get_random_u32() and printk() which need to spin_lock.
 	 */
-	if (!(*alloc_flags & ALLOC_NOLOCK) &&
+	if (!(*fastpath_alloc_flags & ALLOC_NOLOCK) &&
 	    should_fail_alloc_page(gfp_mask, order))
 		return false;
 
-	*alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, *alloc_flags);
+	*fastpath_alloc_flags = cma_alloc_flags(gfp_mask, *fastpath_alloc_flags);
 
 	/* Dirty zone balancing only done in the fast path */
 	ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
@@ -5260,7 +5260,7 @@ struct page *__alloc_frozen_pages_noprof(gfp_t gfp, unsigned int order,
 		int preferred_nid, nodemask_t *nodemask)
 {
 	struct page *page;
-	unsigned int alloc_flags = ALLOC_WMARK_LOW;
+	unsigned int fastpath_alloc_flags = ALLOC_WMARK_LOW;
 	gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */
 	struct alloc_context ac = { };
 
@@ -5282,17 +5282,17 @@ struct page *__alloc_frozen_pages_noprof(gfp_t gfp, unsigned int order,
 	gfp = current_gfp_context(gfp);
 	alloc_gfp = gfp;
 	if (!prepare_alloc_pages(gfp, order, preferred_nid, nodemask, &ac,
-			&alloc_gfp, &alloc_flags))
+			&alloc_gfp, &fastpath_alloc_flags))
 		return NULL;
 
 	/*
 	 * Forbid the first pass from falling back to types that fragment
 	 * memory until all local zones are considered.
 	 */
-	alloc_flags |= alloc_flags_nofragment(zonelist_zone(ac.preferred_zoneref), gfp);
+	fastpath_alloc_flags |= alloc_flags_nofragment(zonelist_zone(ac.preferred_zoneref), gfp);
 
 	/* First allocation attempt */
-	page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac);
+	page = get_page_from_freelist(alloc_gfp, order, fastpath_alloc_flags, &ac);
 	if (likely(page))
 		goto out;
 

-- 
2.54.0