From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f171.google.com (mail-pf0-f171.google.com [209.85.192.171]) by kanga.kvack.org (Postfix) with ESMTP id BD27D6B0253 for ; Thu, 11 Feb 2016 04:29:09 -0500 (EST) Received: by mail-pf0-f171.google.com with SMTP id q63so26723817pfb.0 for ; Thu, 11 Feb 2016 01:29:09 -0800 (PST) Received: from smtprelay.synopsys.com (us01smtprelay-2.synopsys.com. [198.182.47.9]) by mx.google.com with ESMTPS id c8si11490560pat.62.2016.02.11.01.29.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Feb 2016 01:29:08 -0800 (PST) From: Vineet Gupta Subject: [PATCH 1/2] mm,thp: refactor generic deposit/withdraw routines for wider usage Date: Thu, 11 Feb 2016 14:58:26 +0530 Message-ID: <1455182907-15445-2-git-send-email-vgupta@synopsys.com> In-Reply-To: <1455182907-15445-1-git-send-email-vgupta@synopsys.com> References: <1455182907-15445-1-git-send-email-vgupta@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , "Kirill A. Shutemov" Cc: "Aneesh Kumar K.V" , "David S. Miller" , Alex Thorlton , Gerald Schaefer , Martin Schwidefsky , linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Vineet Gupta , Andrea Arcangeli Generic pgtable_trans_huge_deposit()/pgtable_trans_huge_withdraw() assume pgtable_t to be struct page * which is not true for all arches. Thus arc, s390, sparch end up with their own copies despite no special hardware requirements (unlike powerpc). It seems massaging the code a bit can make it reusbale. - Use explicit casts to (struct page *). For existing users, this should be semantically no-op for existing users - The only addition is zero'ing out of page->lru which for arc leaves a stray entry in pgtable_t cause mm spew when such pgtable is freed. | huge_memory: BUG: failure at | ../mm/huge_memory.c:1858/__split_huge_page_map()! | CPU: 0 PID: 901 Comm: bw_mem Not tainted 4.4.0-00015-g0569c1459cfa-dirty | | Stack Trace: | arc_unwind_core.constprop.1+0x94/0x104 | split_huge_page_to_list+0x5c0/0x920 | __split_huge_page_pmd+0xc8/0x1b4 | vma_adjust_trans_huge+0x104/0x1c8 | vma_adjust+0xf8/0x6d8 | __split_vma.isra.40+0xf8/0x174 | do_munmap+0x360/0x428 | SyS_munmap+0x28/0x44 Cc: Kirill A. Shutemov Cc: Aneesh Kumar K.V Cc: Andrea Arcangeli Cc: Andrew Morton Cc: David S. Miller Cc: Alex Thorlton Cc: Gerald Schaefer Cc: Martin Schwidefsky Cc: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-arch@vger.kernel.org Signed-off-by: Vineet Gupta --- mm/pgtable-generic.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c index 75664ed7e3ab..c9f2f6f8c7bb 100644 --- a/mm/pgtable-generic.c +++ b/mm/pgtable-generic.c @@ -155,13 +155,17 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, pgtable_t pgtable) { + struct page *new = (struct page *)pgtable; + struct page *head; + assert_spin_locked(pmd_lockptr(mm, pmdp)); /* FIFO */ - if (!pmd_huge_pte(mm, pmdp)) - INIT_LIST_HEAD(&pgtable->lru); + head = (struct page *)pmd_huge_pte(mm, pmdp); + if (!head) + INIT_LIST_HEAD(&new->lru); else - list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru); + list_add(&new->lru, &head->lru); pmd_huge_pte(mm, pmdp) = pgtable; } #endif @@ -170,20 +174,23 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, /* no "address" argument so destroys page coloring of some arch */ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp) { - pgtable_t pgtable; + struct page *page; assert_spin_locked(pmd_lockptr(mm, pmdp)); + page = (struct page *)pmd_huge_pte(mm, pmdp); + /* FIFO */ - pgtable = pmd_huge_pte(mm, pmdp); - if (list_empty(&pgtable->lru)) + if (list_empty(&page->lru)) pmd_huge_pte(mm, pmdp) = NULL; else { - pmd_huge_pte(mm, pmdp) = list_entry(pgtable->lru.next, - struct page, lru); - list_del(&pgtable->lru); + pmd_huge_pte(mm, pmdp) = (pgtable_t) list_entry(page->lru.next, + struct page, lru); + list_del(&page->lru); } - return pgtable; + + memset(&page->lru, 0, sizeof(page->lru)); + return (pgtable_t)page; } #endif -- 2.5.0 -- 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