Merge "mm: cma: sleep between retries in cma_alloc" (271a1276) · Commits · e / devices / android_kernel_xiaomi_markw

mm/cma.c

+20 −2

Original line number	Diff line number	Diff line
		@@ -33,6 +33,7 @@
		#include <linux/log2.h>
		#include <linux/cma.h>
		#include <linux/highmem.h>
		#include <linux/delay.h>

		struct cma {
		unsigned long base_pfn;
		@@ -344,6 +345,7 @@ struct page cma_alloc(struct cma cma, size_t count, unsigned int align)
		unsigned long bitmap_maxno, bitmap_no, bitmap_count;
		struct page *page = NULL;
		int ret;
		int retry_after_sleep = 0;

		if (!cma \|\| !cma->count)
		return NULL;
		@@ -363,9 +365,25 @@ struct page cma_alloc(struct cma cma, size_t count, unsigned int align)
		bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
		bitmap_maxno, start, bitmap_count, mask);
		if (bitmap_no >= bitmap_maxno) {
		if (retry_after_sleep < 2) {
		start = 0;
		/*
		* Page may be momentarily pinned by some other
		* process which has been scheduled out, eg.
		* in exit path, during unmap call, or process
		* fork and so cannot be freed there. Sleep
		* for 100ms and retry twice to see if it has
		* been freed later.
		*/
		mutex_unlock(&cma->lock);
		msleep(100);
		retry_after_sleep++;
		continue;
		} else {
		mutex_unlock(&cma->lock);
		break;
		}
		}
		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
		/*
		* It's safe to drop the lock here. We've marked this region for