In [1], Joonsoo said that cma_alloc_counter is useless because pageblock is isolated. But if alloc_contig_range meet a busy range, it will undo_isolate_page_range before goto try next range. At this time, __rmqueue_cma can begin allocd CMA memory from the range. So I add cma_alloc_counter let __rmqueue doesn't call __rmqueue_cma when cma_alloc works. [1] https://lkml.org/lkml/2014/10/24/26 Signed-off-by: Hui Zhu <zhuhui@xxxxxxxxxx> --- include/linux/cma.h | 2 ++ mm/cma.c | 6 ++++++ mm/page_alloc.c | 8 +++++++- 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/cma.h b/include/linux/cma.h index 9384ba6..155158f 100644 --- a/include/linux/cma.h +++ b/include/linux/cma.h @@ -26,6 +26,8 @@ extern int __init cma_declare_contiguous(phys_addr_t base, extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, int order_per_bit, struct cma **res_cma); + +extern atomic_t cma_alloc_counter; extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align); extern bool cma_release(struct cma *cma, struct page *pages, int count); #endif diff --git a/mm/cma.c b/mm/cma.c index 6707b5d..b63f6be 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -348,6 +348,8 @@ err: return ret; } +atomic_t cma_alloc_counter = ATOMIC_INIT(0); + /** * cma_alloc() - allocate pages from contiguous area * @cma: Contiguous memory region for which the allocation is performed. @@ -378,6 +380,8 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align) bitmap_maxno = cma_bitmap_maxno(cma); bitmap_count = cma_bitmap_pages_to_bits(cma, count); + atomic_inc(&cma_alloc_counter); + for (;;) { mutex_lock(&cma->lock); bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, @@ -415,6 +419,8 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align) start = bitmap_no + mask + 1; } + atomic_dec(&cma_alloc_counter); + pr_debug("%s(): returned %p\n", __func__, page); return page; } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a5bbc38..0622c4c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -66,6 +66,10 @@ #include <asm/div64.h> #include "internal.h" +#ifdef CONFIG_CMA +#include <linux/cma.h> +#endif + /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */ static DEFINE_MUTEX(pcp_batch_high_lock); #define MIN_PERCPU_PAGELIST_FRACTION (8) @@ -1330,7 +1334,9 @@ static struct page *__rmqueue(struct zone *zone, unsigned int order, { struct page *page = NULL; - if (IS_ENABLED(CONFIG_CMA) && zone->managed_cma_pages) { + if (IS_ENABLED(CONFIG_CMA) + && zone->managed_cma_pages + && atomic_read(&cma_alloc_counter) == 0) { if (migratetype == MIGRATE_MOVABLE && zone->nr_try_movable <= 0) page = __rmqueue_cma(zone, order); -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>