linux-kernel - [PATCH mm-unstable v1 2/3] mm/cma: add cma_alloc

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Message-ID: <20240811212129.3074314-3-yuzhao@google.com>
Date: Sun, 11 Aug 2024 15:21:28 -0600
From: Yu Zhao <yuzhao@...gle.com>
To: Andrew Morton <akpm@...ux-foundation.org>, Muchun Song <muchun.song@...ux.dev>
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>, Zi Yan <ziy@...dia.com>, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org, Yu Zhao <yuzhao@...gle.com>
Subject: [PATCH mm-unstable v1 2/3] mm/cma: add cma_alloc_folio()

With alloc_contig_range() and free_contig_range() supporting large
folios, CMA can allocate and free large folios too, by
cma_alloc_folio() and cma_release().

Signed-off-by: Yu Zhao <yuzhao@...gle.com>
---
 include/linux/cma.h |  1 +
 mm/cma.c            | 47 ++++++++++++++++++++++++++++++---------------
 2 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 9db877506ea8..086553fbda73 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -46,6 +46,7 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 					struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, unsigned long count, unsigned int align,
 			      bool no_warn);
+extern struct folio *cma_alloc_folio(struct cma *cma, int order, gfp_t gfp);
 extern bool cma_pages_valid(struct cma *cma, const struct page *pages, unsigned long count);
 extern bool cma_release(struct cma *cma, const struct page *pages, unsigned long count);
 
diff --git a/mm/cma.c b/mm/cma.c
index 95d6950e177b..46feb06db8e7 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -403,18 +403,8 @@ static void cma_debug_show_areas(struct cma *cma)
 	spin_unlock_irq(&cma->lock);
 }
 
-/**
- * cma_alloc() - allocate pages from contiguous area
- * @cma:   Contiguous memory region for which the allocation is performed.
- * @count: Requested number of pages.
- * @align: Requested alignment of pages (in PAGE_SIZE order).
- * @no_warn: Avoid printing message about failed allocation
- *
- * This function allocates part of contiguous memory on specific
- * contiguous memory area.
- */
-struct page *cma_alloc(struct cma *cma, unsigned long count,
-		       unsigned int align, bool no_warn)
+static struct page *__cma_alloc(struct cma *cma, unsigned long count,
+				unsigned int align, gfp_t gfp)
 {
 	unsigned long mask, offset;
 	unsigned long pfn = -1;
@@ -463,8 +453,7 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
 
 		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 		mutex_lock(&cma_mutex);
-		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
-				     GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
+		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, gfp);
 		mutex_unlock(&cma_mutex);
 		if (ret == 0) {
 			page = pfn_to_page(pfn);
@@ -494,7 +483,7 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
 			page_kasan_tag_reset(nth_page(page, i));
 	}
 
-	if (ret && !no_warn) {
+	if (ret && !(gfp & __GFP_NOWARN)) {
 		pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n",
 				   __func__, cma->name, count, ret);
 		cma_debug_show_areas(cma);
@@ -513,6 +502,34 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
 	return page;
 }
 
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma:   Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ * @no_warn: Avoid printing message about failed allocation
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, unsigned long count,
+		       unsigned int align, bool no_warn)
+{
+	return __cma_alloc(cma, count, align, GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
+}
+
+struct folio *cma_alloc_folio(struct cma *cma, int order, gfp_t gfp)
+{
+	struct page *page;
+
+	if (WARN_ON(order && !(gfp | __GFP_COMP)))
+		return NULL;
+
+	page = __cma_alloc(cma, 1 << order, order, gfp);
+
+	return page ? page_folio(page) : NULL;
+}
+
 bool cma_pages_valid(struct cma *cma, const struct page *pages,
 		     unsigned long count)
 {
-- 
2.46.0.76.ge559c4bf1a-goog