[1/2] drm/ttm: swap consecutive allocated cached pages v2

Commit Message

He, Hongbo Dec. 4, 2017, 12:22 p.m. UTC

-----Original Message-----
From: Christian König [mailto:[e-mail]] 
Sent: Monday, December 04, 2017 8:13 PM
To: [e-mail]; [e-mail]; He, Roger <[e-mail]>; [e-mail]
Subject: [PATCH 1/2] drm/ttm: swap consecutive allocated cached pages v2

When we detect consecutive allocation of pages swap them to avoid accidentally freeing them as huge page.

v2: use swap

Signed-off-by: Christian König <[e-mail]>
---
 drivers/gpu/drm/ttm/ttm_page_alloc.c | 4 ++++
 1 file changed, 4 insertions(+)

				return -ENOMEM;
			}
			
			/* Swap the pages if we detect consecutive order */
			if (i > first && pages[i - 1] == p - 1)                                          //change to (i > first), because I worry if npages is 513, the first regular page is exactly consecutive with last page of huge page. Then swap them is not what I want here.
				swap(p, pages[i - 1]);

			pages[i++] = p;
			--npages;
		}

 			pages[i++] = p;
 			--npages;
 		}
--
2.11.0

Patch

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
index c82d94cbbabc..b6c5148607e9 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -921,6 +921,10 @@  static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
 				return -ENOMEM;
 			}
 
How about add first index as below?

		first = i;  //init  first here
		while (npages) {
			p = alloc_page(gfp_flags);
			if (!p) {
				pr_debug("Unable to allocate page\n");