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-rw-r--r--mm/cma.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/mm/cma.c b/mm/cma.c
index 2906ae5a83ff..a6033e344430 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -348,6 +348,32 @@ err:
return ret;
}
+#ifdef CONFIG_CMA_DEBUG
+static void cma_debug_show_areas(struct cma *cma)
+{
+ unsigned long next_zero_bit, next_set_bit;
+ unsigned long start = 0;
+ unsigned int nr_zero, nr_total = 0;
+
+ mutex_lock(&cma->lock);
+ pr_info("number of available pages: ");
+ for (;;) {
+ next_zero_bit = find_next_zero_bit(cma->bitmap, cma->count, start);
+ if (next_zero_bit >= cma->count)
+ break;
+ next_set_bit = find_next_bit(cma->bitmap, cma->count, next_zero_bit);
+ nr_zero = next_set_bit - next_zero_bit;
+ pr_cont("%s%u@%lu", nr_total ? "+" : "", nr_zero, next_zero_bit);
+ nr_total += nr_zero;
+ start = next_zero_bit + nr_zero;
+ }
+ pr_cont("=> %u free of %lu total pages\n", nr_total, cma->count);
+ mutex_unlock(&cma->lock);
+}
+#else
+static inline void cma_debug_show_areas(struct cma *cma) { }
+#endif
+
/**
* cma_alloc() - allocate pages from contiguous area
* @cma: Contiguous memory region for which the allocation is performed.
@@ -365,7 +391,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
unsigned long start = 0;
unsigned long bitmap_maxno, bitmap_no, bitmap_count;
struct page *page = NULL;
- int ret;
+ int ret = -ENOMEM;
if (!cma || !cma->count)
return NULL;
@@ -423,6 +449,12 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
trace_cma_alloc(pfn, page, count, align);
+ if (ret) {
+ pr_info("%s: alloc failed, req-size: %zu pages, ret: %d\n",
+ __func__, count, ret);
+ cma_debug_show_areas(cma);
+ }
+
pr_debug("%s(): returned %p\n", __func__, page);
return page;
}