linux-kernel - Re: [PATCH 1/4] mm, page_owner: make init_pages_in

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Date:   Thu, 24 Aug 2017 09:01:52 +0200
From:   Vlastimil Babka <vbabka@...e.cz>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Yang Shi <yang.shi@...aro.org>,
        Laura Abbott <labbott@...hat.com>,
        Vinayak Menon <vinmenon@...eaurora.org>,
        zhong jiang <zhongjiang@...wei.com>
Subject: Re: [PATCH 1/4] mm, page_owner: make init_pages_in_zone() faster

On 08/23/2017 08:47 AM, Vlastimil Babka wrote:
> On 07/24/2017 02:38 PM, Michal Hocko wrote:
>>
>> Do we need to duplicated a part of __set_page_owner? Can we pull out
>> both owner and handle out __set_page_owner?
> 
> I wanted to avoid overhead in __set_page_owner() by introducing extra
> shared function, but I'll check if that can be helped.

Ok, here's a -fix for that.

----8<----
>From b607d021d52c5f4b64874a7e738a62e3f0e5ddea Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@...e.cz>
Date: Thu, 24 Aug 2017 08:39:58 +0200
Subject: [PATCH] mm, page_owner: make init_pages_in_zone() faster-fix

Don't duplicate code of __set_page_owner(), per Michal Hocko.
---
 mm/page_owner.c | 31 +++++++++++++------------------
 1 file changed, 13 insertions(+), 18 deletions(-)

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 5aa21ca237d9..cd72a74d41a0 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -165,17 +165,13 @@ static noinline depot_stack_handle_t save_stack(gfp_t flags)
 	return handle;
 }
 
-noinline void __set_page_owner(struct page *page, unsigned int order,
-					gfp_t gfp_mask)
+static inline void __set_page_owner_handle(struct page_ext *page_ext,
+	depot_stack_handle_t handle, unsigned int order, gfp_t gfp_mask)
 {
-	struct page_ext *page_ext = lookup_page_ext(page);
 	struct page_owner *page_owner;
 
-	if (unlikely(!page_ext))
-		return;
-
 	page_owner = get_page_owner(page_ext);
-	page_owner->handle = save_stack(gfp_mask);
+	page_owner->handle = handle;
 	page_owner->order = order;
 	page_owner->gfp_mask = gfp_mask;
 	page_owner->last_migrate_reason = -1;
@@ -183,18 +179,17 @@ noinline void __set_page_owner(struct page *page, unsigned int order,
 	__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
 }
 
-static void __set_page_owner_init(struct page_ext *page_ext,
-					depot_stack_handle_t handle)
+noinline void __set_page_owner(struct page *page, unsigned int order,
+					gfp_t gfp_mask)
 {
-	struct page_owner *page_owner;
+	struct page_ext *page_ext = lookup_page_ext(page);
+	depot_stack_handle_t handle;
 
-	page_owner = get_page_owner(page_ext);
-	page_owner->handle = handle;
-	page_owner->order = 0;
-	page_owner->gfp_mask = 0;
-	page_owner->last_migrate_reason = -1;
+	if (unlikely(!page_ext))
+		return;
 
-	__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
+	handle = save_stack(gfp_mask);
+	__set_page_owner_handle(page_ext, handle, order, gfp_mask);
 }
 
 void __set_page_owner_migrate_reason(struct page *page, int reason)
@@ -582,12 +577,12 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 			if (unlikely(!page_ext))
 				continue;
 
-			/* Maybe overraping zone */
+			/* Maybe overlaping zone */
 			if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 				continue;
 
 			/* Found early allocated page */
-			__set_page_owner_init(page_ext, init_handle);
+			__set_page_owner_handle(page_ext, init_handle, 0, 0);
 			count++;
 		}
 	}
-- 
2.14.1