From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f53.google.com (mail-pa0-f53.google.com [209.85.220.53]) by kanga.kvack.org (Postfix) with ESMTP id BEC7182F64 for ; Thu, 5 Nov 2015 03:09:58 -0500 (EST) Received: by pasz6 with SMTP id z6so83436930pas.2 for ; Thu, 05 Nov 2015 00:09:58 -0800 (PST) Received: from lgeamrelo13.lge.com (LGEAMRELO13.lge.com. [156.147.23.53]) by mx.google.com with ESMTPS id xg5si8421177pab.13.2015.11.05.00.09.56 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 05 Nov 2015 00:09:57 -0800 (PST) Date: Thu, 5 Nov 2015 17:10:05 +0900 From: Joonsoo Kim Subject: Re: [PATCH 3/5] mm, page_owner: copy page owner info during migration Message-ID: <20151105081005.GB25938@js1304-P5Q-DELUXE> References: <1446649261-27122-1-git-send-email-vbabka@suse.cz> <1446649261-27122-4-git-send-email-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1446649261-27122-4-git-send-email-vbabka@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Minchan Kim , Sasha Levin , "Kirill A. Shutemov" , Mel Gorman On Wed, Nov 04, 2015 at 04:00:59PM +0100, Vlastimil Babka wrote: > The page_owner mechanism stores gfp_flags of an allocation and stack trace > that lead to it. During page migration, the original information is > essentially replaced by the allocation of free page as the migration target. > Arguably this is less useful and might lead to all the page_owner info for > migratable pages gradually converge towards compaction or numa balancing > migrations. It has also lead to inaccuracies such as one fixed by commit > e2cfc91120fa ("mm/page_owner: set correct gfp_mask on page_owner"). > > This patch thus introduces copying the page_owner info during migration. > However, since the fact that the page has been migrated from its original > place might be useful for debugging, the next patch will introduce a way to > track that information as well. > > Signed-off-by: Vlastimil Babka > --- > include/linux/page_owner.h | 10 +++++++++- > mm/migrate.c | 2 ++ > mm/page_owner.c | 16 ++++++++++++++++ > 3 files changed, 27 insertions(+), 1 deletion(-) > > diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h > index 8e2eb15..6440daa 100644 > --- a/include/linux/page_owner.h > +++ b/include/linux/page_owner.h > @@ -11,6 +11,7 @@ extern void __reset_page_owner(struct page *page, unsigned int order); > extern void __set_page_owner(struct page *page, > unsigned int order, gfp_t gfp_mask); > extern gfp_t __get_page_owner_gfp(struct page *page); > +extern void __copy_page_owner(struct page *oldpage, struct page *newpage); > > static inline void reset_page_owner(struct page *page, unsigned int order) > { > @@ -32,6 +33,11 @@ static inline gfp_t get_page_owner_gfp(struct page *page) > else > return 0; > } > +static inline void copy_page_owner(struct page *oldpage, struct page *newpage) > +{ > + if (static_branch_unlikely(&page_owner_inited)) > + __copy_page_owner(oldpage, newpage); > +} > #else > static inline void reset_page_owner(struct page *page, unsigned int order) > { > @@ -44,6 +50,8 @@ static inline gfp_t get_page_owner_gfp(struct page *page) > { > return 0; > } > - > +static inline void copy_page_owner(struct page *oldpage, struct page *newpage) > +{ > +} > #endif /* CONFIG_PAGE_OWNER */ > #endif /* __LINUX_PAGE_OWNER_H */ > diff --git a/mm/migrate.c b/mm/migrate.c > index 1ae0113..9f82e03 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -38,6 +38,7 @@ > #include > #include > #include > +#include > > #include > > @@ -775,6 +776,7 @@ static int move_to_new_page(struct page *newpage, struct page *page, > set_page_memcg(page, NULL); > if (!PageAnon(page)) > page->mapping = NULL; > + copy_page_owner(page, newpage); > } > return rc; > } > diff --git a/mm/page_owner.c b/mm/page_owner.c > index 7664b85..7ebd3d0 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -84,6 +84,22 @@ gfp_t __get_page_owner_gfp(struct page *page) > return page_ext->gfp_mask; > } > > +void __copy_page_owner(struct page *oldpage, struct page *newpage) > +{ > + struct page_ext *old_ext = lookup_page_ext(oldpage); > + struct page_ext *new_ext = lookup_page_ext(newpage); > + int i; > + > + new_ext->order = old_ext->order; > + new_ext->gfp_mask = old_ext->gfp_mask; > + new_ext->nr_entries = old_ext->nr_entries; > + > + for (i = 0; i < ARRAY_SIZE(new_ext->trace_entries); i++) > + new_ext->trace_entries[i] = old_ext->trace_entries[i]; > + > + __set_bit(PAGE_EXT_OWNER, &new_ext->flags); > +} > + Need to clear PAGE_EXT_OWNER bit in oldppage. Thanks. > static ssize_t > print_page_owner(char __user *buf, size_t count, unsigned long pfn, > struct page *page, struct page_ext *page_ext) > -- > 2.6.2 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org