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From:   js1304@gmail.com
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        kernel-team@lge.com, Vlastimil Babka <vbabka@suse.cz>,
        Christoph Hellwig <hch@infradead.org>,
        Roman Gushchin <guro@fb.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Michal Hocko <mhocko@suse.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: [PATCH v4 03/11] mm/hugetlb: unify migration callbacks
Date:   Tue,  7 Jul 2020 16:44:41 +0900
Message-Id: <1594107889-32228-4-git-send-email-iamjoonsoo.kim@lge.com>
In-Reply-To: <1594107889-32228-1-git-send-email-iamjoonsoo.kim@lge.com>
References: <1594107889-32228-1-git-send-email-iamjoonsoo.kim@lge.com>
Sender: linux-kernel-owner@vger.kernel.org
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From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

There is no difference between two migration callback functions,
alloc_huge_page_node() and alloc_huge_page_nodemask(), except
__GFP_THISNODE handling. It's redundant to have two almost similar
functions in order to handle this flag. So, this patch tries to
remove one by introducing a new argument, gfp_mask, to
alloc_huge_page_nodemask().

After introducing gfp_mask argument, it's caller's job to provide correct
gfp_mask. So, every callsites for alloc_huge_page_nodemask() are changed
to provide gfp_mask.

Note that it's safe to remove a node id check in alloc_huge_page_node()
since there is no caller passing NUMA_NO_NODE as a node id.

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 include/linux/hugetlb.h | 26 ++++++++++++++++++--------
 mm/hugetlb.c            | 35 ++---------------------------------
 mm/mempolicy.c          | 10 ++++++----
 mm/migrate.c            | 11 +++++++----
 4 files changed, 33 insertions(+), 49 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 50650d0..bb93e95 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -10,6 +10,7 @@
 #include <linux/list.h>
 #include <linux/kref.h>
 #include <linux/pgtable.h>
+#include <linux/gfp.h>
 
 struct ctl_table;
 struct user_struct;
@@ -504,9 +505,8 @@ struct huge_bootmem_page {
 
 struct page *alloc_huge_page(struct vm_area_struct *vma,
 				unsigned long addr, int avoid_reserve);
-struct page *alloc_huge_page_node(struct hstate *h, int nid);
 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
-				nodemask_t *nmask);
+				nodemask_t *nmask, gfp_t gfp_mask);
 struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
 				unsigned long address);
 struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
@@ -692,6 +692,15 @@ static inline bool hugepage_movable_supported(struct hstate *h)
 	return true;
 }
 
+/* Movability of hugepages depends on migration support. */
+static inline gfp_t htlb_alloc_mask(struct hstate *h)
+{
+	if (hugepage_movable_supported(h))
+		return GFP_HIGHUSER_MOVABLE;
+	else
+		return GFP_HIGHUSER;
+}
+
 static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
 					   struct mm_struct *mm, pte_t *pte)
 {
@@ -759,13 +768,9 @@ static inline struct page *alloc_huge_page(struct vm_area_struct *vma,
 	return NULL;
 }
 
-static inline struct page *alloc_huge_page_node(struct hstate *h, int nid)
-{
-	return NULL;
-}
-
 static inline struct page *
-alloc_huge_page_nodemask(struct hstate *h, int preferred_nid, nodemask_t *nmask)
+alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
+			nodemask_t *nmask, gfp_t gfp_mask)
 {
 	return NULL;
 }
@@ -878,6 +883,11 @@ static inline bool hugepage_movable_supported(struct hstate *h)
 	return false;
 }
 
+static inline gfp_t htlb_alloc_mask(struct hstate *h)
+{
+	return 0;
+}
+
 static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
 					   struct mm_struct *mm, pte_t *pte)
 {
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 7e5ba5c0..3245aa0 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1089,15 +1089,6 @@ static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask,
 	return NULL;
 }
 
-/* Movability of hugepages depends on migration support. */
-static inline gfp_t htlb_alloc_mask(struct hstate *h)
-{
-	if (hugepage_movable_supported(h))
-		return GFP_HIGHUSER_MOVABLE;
-	else
-		return GFP_HIGHUSER;
-}
-
 static struct page *dequeue_huge_page_vma(struct hstate *h,
 				struct vm_area_struct *vma,
 				unsigned long address, int avoid_reserve,
@@ -1979,31 +1970,9 @@ struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
 }
 
 /* page migration callback function */
-struct page *alloc_huge_page_node(struct hstate *h, int nid)
-{
-	gfp_t gfp_mask = htlb_alloc_mask(h);
-	struct page *page = NULL;
-
-	if (nid != NUMA_NO_NODE)
-		gfp_mask |= __GFP_THISNODE;
-
-	spin_lock(&hugetlb_lock);
-	if (h->free_huge_pages - h->resv_huge_pages > 0)
-		page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL);
-	spin_unlock(&hugetlb_lock);
-
-	if (!page)
-		page = alloc_migrate_huge_page(h, gfp_mask, nid, NULL);
-
-	return page;
-}
-
-/* page migration callback function */
 struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
-		nodemask_t *nmask)
+		nodemask_t *nmask, gfp_t gfp_mask)
 {
-	gfp_t gfp_mask = htlb_alloc_mask(h);
-
 	spin_lock(&hugetlb_lock);
 	if (h->free_huge_pages - h->resv_huge_pages > 0) {
 		struct page *page;
@@ -2031,7 +2000,7 @@ struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
 
 	gfp_mask = htlb_alloc_mask(h);
 	node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
-	page = alloc_huge_page_nodemask(h, node, nodemask);
+	page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
 	mpol_cond_put(mpol);
 
 	return page;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index dabcee8..9034a53 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1068,10 +1068,12 @@ static int migrate_page_add(struct page *page, struct list_head *pagelist,
 /* page allocation callback for NUMA node migration */
 struct page *alloc_new_node_page(struct page *page, unsigned long node)
 {
-	if (PageHuge(page))
-		return alloc_huge_page_node(page_hstate(compound_head(page)),
-					node);
-	else if (PageTransHuge(page)) {
+	if (PageHuge(page)) {
+		struct hstate *h = page_hstate(compound_head(page));
+		gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
+
+		return alloc_huge_page_nodemask(h, node, NULL, gfp_mask);
+	} else if (PageTransHuge(page)) {
 		struct page *thp;
 
 		thp = alloc_pages_node(node,
diff --git a/mm/migrate.c b/mm/migrate.c
index 7370a66..3b3d918 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1538,10 +1538,13 @@ struct page *new_page_nodemask(struct page *page,
 	unsigned int order = 0;
 	struct page *new_page = NULL;
 
-	if (PageHuge(page))
-		return alloc_huge_page_nodemask(
-				page_hstate(compound_head(page)),
-				preferred_nid, nodemask);
+	if (PageHuge(page)) {
+		struct hstate *h = page_hstate(compound_head(page));
+
+		gfp_mask = htlb_alloc_mask(h);
+		return alloc_huge_page_nodemask(h, preferred_nid,
+						nodemask, gfp_mask);
+	}
 
 	if (PageTransHuge(page)) {
 		gfp_mask |= GFP_TRANSHUGE;
-- 
2.7.4