mm/hugetlb: make hugetlb migration callback CMA aware

new_non_cma_page() in gup.c requires to allocate the new page that is not
on the CMA area.  new_non_cma_page() implements it by using allocation
scope APIs.

However, there is a work-around for hugetlb.  Normal hugetlb page
allocation API for migration is alloc_huge_page_nodemask().  It consists
of two steps.  First is dequeing from the pool.  Second is, if there is no
available page on the queue, allocating by using the page allocator.

new_non_cma_page() can't use this API since first step (deque) isn't aware
of scope API to exclude CMA area.  So, new_non_cma_page() exports hugetlb
internal function for the second step, alloc_migrate_huge_page(), to
global scope and uses it directly.  This is suboptimal since hugetlb pages
on the queue cannot be utilized.

This patch tries to fix this situation by making the deque function on
hugetlb CMA aware.  In the deque function, CMA memory is skipped if
PF_MEMALLOC_NOCMA flag is found.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1596180906-8442-2-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index d86c82749836b43b738dd67f167f82e7f9e2d124..d5cc5f802dd4b6ce5bc755ab14e3f6aae316ecfc 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -511,8 +511,6 @@ struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
                                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,
-                                    int nid, nodemask_t *nmask);
 int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
                        pgoff_t idx);
 

diff --git a/mm/gup.c b/mm/gup.c
index 6c20c6e376354b09ed0a7aeca2c977c6f316f186..c55427beeb26ca6527fae1a5bc1f6bf68fcb21da 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1635,11 +1635,7 @@ static struct page *new_non_cma_page(struct page *page, unsigned long private)
                struct hstate *h = page_hstate(page);
 
                gfp_mask = htlb_modify_alloc_mask(h, gfp_mask);
-               /*
-                * We don't want to dequeue from the pool because pool pages will
-                * mostly be from the CMA region.
-                */
-               return alloc_migrate_huge_page(h, gfp_mask, nid, NULL);
+               return alloc_huge_page_nodemask(h, nid, NULL, gfp_mask);
        }
 #endif
        if (PageTransHuge(page)) {

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index eaab9ef88e9db994b82f91d82a5669448a3964f2..a301c2d672bf5246f1ec4bf709374b3b78489189 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -19,6 +19,7 @@
 #include <linux/memblock.h>
 #include <linux/sysfs.h>
 #include <linux/slab.h>
+#include <linux/sched/mm.h>
 #include <linux/mmdebug.h>
 #include <linux/sched/signal.h>
 #include <linux/rmap.h>
@@ -1040,10 +1041,16 @@ static void enqueue_huge_page(struct hstate *h, struct page *page)
 static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
 {
        struct page *page;
+       bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);
+
+       list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
+               if (nocma && is_migrate_cma_page(page))
+                       continue;
 
-       list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
                if (!PageHWPoison(page))
                        break;
+       }
+
        /*
         * if 'non-isolated free hugepage' not found on the list,
         * the allocation fails.
@@ -1935,7 +1942,7 @@ out_unlock:
        return page;
 }
 
-struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
+static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
                                     int nid, nodemask_t *nmask)
 {
        struct page *page;