linux-kernel - [PATCH 5/6] mm: honor PF_MEMALLOC

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Message-Id: <20201202052330.474592-6-pasha.tatashin@soleen.com>
Date:   Wed,  2 Dec 2020 00:23:29 -0500
From:   Pavel Tatashin <pasha.tatashin@...een.com>
To:     pasha.tatashin@...een.com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, akpm@...ux-foundation.org, vbabka@...e.cz,
        mhocko@...e.com, david@...hat.com, osalvador@...e.de,
        dan.j.williams@...el.com, sashal@...nel.org,
        tyhicks@...ux.microsoft.com, iamjoonsoo.kim@....com,
        mike.kravetz@...cle.com, rostedt@...dmis.org, mingo@...hat.com,
        jgg@...pe.ca, peterz@...radead.org, mgorman@...e.de,
        willy@...radead.org, rientjes@...gle.com, jhubbard@...dia.com
Subject: [PATCH 5/6] mm: honor PF_MEMALLOC_NOMOVABLE for all allocations

PF_MEMALLOC_NOMOVABLE is only honored for CMA allocations, extend
this flag to work for any allocations by removing __GFP_MOVABLE from
gfp_mask when this flag is passed in the current context, thus
prohibiting allocations from ZONE_MOVABLE.

Signed-off-by: Pavel Tatashin <pasha.tatashin@...een.com>
---
 mm/hugetlb.c    |  2 +-
 mm/page_alloc.c | 26 ++++++++++++++++----------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 02213c74ed6b..00e786201d8b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1036,7 +1036,7 @@ static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
 	bool nomovable = !!(current->flags & PF_MEMALLOC_NOMOVABLE);
 
 	list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
-		if (nomovable && is_migrate_cma_page(page))
+		if (nomovable && is_migrate_movable(get_pageblock_migratetype(page)))
 			continue;
 
 		if (PageHWPoison(page))
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 611799c72da5..7a6d86d0bc5f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3766,20 +3766,25 @@ alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
 	return alloc_flags;
 }
 
-static inline unsigned int current_alloc_flags(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
-	unsigned int pflags = current->flags;
-
-	if (!(pflags & PF_MEMALLOC_NOMOVABLE) &&
-	    gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)
+	if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)
 		alloc_flags |= ALLOC_CMA;
-
 #endif
 	return alloc_flags;
 }
 
+static inline gfp_t current_gfp_checkmovable(gfp_t gfp_mask)
+{
+	unsigned int pflags = current->flags;
+
+	if ((pflags & PF_MEMALLOC_NOMOVABLE))
+		return gfp_mask & ~__GFP_MOVABLE;
+	return gfp_mask;
+}
+
 /*
  * get_page_from_freelist goes through the zonelist trying to allocate
  * a page.
@@ -4423,7 +4428,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
 	} else if (unlikely(rt_task(current)) && !in_interrupt())
 		alloc_flags |= ALLOC_HARDER;
 
-	alloc_flags = current_alloc_flags(gfp_mask, alloc_flags);
+	alloc_flags = cma_alloc_flags(gfp_mask, alloc_flags);
 
 	return alloc_flags;
 }
@@ -4725,7 +4730,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 
 	reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
 	if (reserve_flags)
-		alloc_flags = current_alloc_flags(gfp_mask, reserve_flags);
+		alloc_flags = cma_alloc_flags(gfp_mask, reserve_flags);
 
 	/*
 	 * Reset the nodemask and zonelist iterators if memory policies can be
@@ -4894,7 +4899,7 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
 	if (should_fail_alloc_page(gfp_mask, order))
 		return false;
 
-	*alloc_flags = current_alloc_flags(gfp_mask, *alloc_flags);
+	*alloc_flags = cma_alloc_flags(gfp_mask, *alloc_flags);
 
 	/* Dirty zone balancing only done in the fast path */
 	ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
@@ -4932,6 +4937,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
 	}
 
 	gfp_mask &= gfp_allowed_mask;
+	gfp_mask = current_gfp_checkmovable(gfp_mask);
 	alloc_mask = gfp_mask;
 	if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
 		return NULL;
-- 
2.25.1