Re: [PATCH v3] mm/hugetlb: avoid hardcoding while checking if cma is enable

[Mike Kravetz]

Looks like this produced a warning in linux-next.  I suspect it is due to the
combination CONFIG_HUGETLB_PAGE && !CONFIG_CMA.

Instead of adding the routine hugetlb_cma_enabled() to scan the hugetlb_cma
array, could we just use a boolean as follows?  It can simply be set in
hugetlb_cma_reserve when we reserve CMA.
-- 
Mike Kravetz

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index fab4485b9e52..92cb882cf287 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -46,6 +46,7 @@ unsigned int default_hstate_idx;
 struct hstate hstates[HUGE_MAX_HSTATE];
 
 static struct cma *hugetlb_cma[MAX_NUMNODES];
+static bool hugetlb_cma_enabled = false;
 
 /*
  * Minimum page order among possible hugepage sizes, set to a proper value
@@ -2571,7 +2572,7 @@ static void __init hugetlb_hstate_alloc_pages(struct 
hstate *h)
 
        for (i = 0; i < h->max_huge_pages; ++i) {
                if (hstate_is_gigantic(h)) {
-                       if (IS_ENABLED(CONFIG_CMA) && hugetlb_cma[0]) {
+                       if (hugetlb_cma_enabled) {
                                pr_warn_once("HugeTLB: hugetlb_cma is enabled, 
skip boot time allocation\n");
                                break;
                        }
@@ -5708,6 +5709,7 @@ void __init hugetlb_cma_reserve(int order)
                reserved += size;
                pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
                        size / SZ_1M, nid);
+               hugetlb_cma_enabled = true;
 
                if (reserved >= hugetlb_cma_size)
                        break;