From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration Date: Thu, 13 Sep 2012 15:19:22 -0700 Message-ID: <20120913151922.b8893088.akpm@linux-foundation.org> References: <1347324112-14134-1-git-send-email-minchan@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:50838 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752023Ab2IMWTX (ORCPT ); Thu, 13 Sep 2012 18:19:23 -0400 In-Reply-To: Sender: linux-next-owner@vger.kernel.org List-ID: To: Geert Uytterhoeven Cc: Minchan Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kyungmin Park , Marek Szyprowski , Michal Nazarewicz , Rik van Riel , Mel Gorman , Linux-Next On Thu, 13 Sep 2012 21:17:19 +0200 Geert Uytterhoeven wrote: > On Tue, Sep 11, 2012 at 2:41 AM, Minchan Kim wrote: > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -674,8 +674,10 @@ static enum page_references page_check_references(struct page *page, > > static unsigned long shrink_page_list(struct list_head *page_list, > > struct zone *zone, > > struct scan_control *sc, > > + enum ttu_flags ttu_flags, > > "enum ttu_flags" is defined on CONFIG_MMU=y only, causing on nommu: > > mm/vmscan.c:677:26: error: parameter 4 ('ttu_flags') has incomplete type > mm/vmscan.c:987:5: error: 'TTU_UNMAP' undeclared (first use in this function) > mm/vmscan.c:987:15: error: 'TTU_IGNORE_ACCESS' undeclared (first use > in this function) > mm/vmscan.c:1312:56: error: 'TTU_UNMAP' undeclared (first use in this function) > > E.g. > http://kisskb.ellerman.id.au/kisskb/buildresult/7191694/ (h8300-defconfig) > http://kisskb.ellerman.id.au/kisskb/buildresult/7191858/ (sh-allnoconfig) hm, OK, the means by which current mainline avoids build errors is either clever or lucky. switch (try_to_unmap(page, TTU_UNMAP)) { gets preprocessed into switch (2) { so the cmopiler never gets to see the TTU_ symbol at all. Because it happens to be inside the try_to_unmap() call. I guess we can just make ttu_flags visible to NOMMU: --- a/include/linux/rmap.h~mm-cma-discard-clean-pages-during-contiguous-allocation-instead-of-migration-fix-fix +++ a/include/linux/rmap.h @@ -71,6 +71,17 @@ struct anon_vma_chain { #endif }; +enum ttu_flags { + TTU_UNMAP = 0, /* unmap mode */ + TTU_MIGRATION = 1, /* migration mode */ + TTU_MUNLOCK = 2, /* munlock mode */ + TTU_ACTION_MASK = 0xff, + + TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */ + TTU_IGNORE_ACCESS = (1 << 9), /* don't age */ + TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */ +}; + #ifdef CONFIG_MMU static inline void get_anon_vma(struct anon_vma *anon_vma) { @@ -164,16 +175,6 @@ int page_referenced(struct page *, int i int page_referenced_one(struct page *, struct vm_area_struct *, unsigned long address, unsigned int *mapcount, unsigned long *vm_flags); -enum ttu_flags { - TTU_UNMAP = 0, /* unmap mode */ - TTU_MIGRATION = 1, /* migration mode */ - TTU_MUNLOCK = 2, /* munlock mode */ - TTU_ACTION_MASK = 0xff, - - TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */ - TTU_IGNORE_ACCESS = (1 << 9), /* don't age */ - TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */ -}; #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK) int try_to_unmap(struct page *, enum ttu_flags flags); _