From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f48.google.com (mail-wm0-f48.google.com [74.125.82.48]) by kanga.kvack.org (Postfix) with ESMTP id 45FE56B0038 for ; Thu, 12 Nov 2015 06:26:24 -0500 (EST) Received: by wmdw130 with SMTP id w130so149864314wmd.0 for ; Thu, 12 Nov 2015 03:26:23 -0800 (PST) Received: from mail-wm0-x229.google.com (mail-wm0-x229.google.com. [2a00:1450:400c:c09::229]) by mx.google.com with ESMTPS id c9si17925865wje.210.2015.11.12.03.26.22 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 12 Nov 2015 03:26:23 -0800 (PST) Received: by wmec201 with SMTP id c201so86742356wme.1 for ; Thu, 12 Nov 2015 03:26:22 -0800 (PST) Date: Thu, 12 Nov 2015 13:26:20 +0200 From: "Kirill A. Shutemov" Subject: Re: [PATCH v3 01/17] mm: support madvise(MADV_FREE) Message-ID: <20151112112620.GB22481@node.shutemov.name> References: <1447302793-5376-1-git-send-email-minchan@kernel.org> <1447302793-5376-2-git-send-email-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1447302793-5376-2-git-send-email-minchan@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michael Kerrisk , linux-api@vger.kernel.org, Hugh Dickins , Johannes Weiner , Rik van Riel , Mel Gorman , KOSAKI Motohiro , Jason Evans , Daniel Micay , Shaohua Li , Michal Hocko , yalin.wang2010@gmail.com On Thu, Nov 12, 2015 at 01:32:57PM +0900, Minchan Kim wrote: > @@ -256,6 +260,125 @@ static long madvise_willneed(struct vm_area_struct *vma, > return 0; > } > > +static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, > + unsigned long end, struct mm_walk *walk) > + > +{ > + struct mmu_gather *tlb = walk->private; > + struct mm_struct *mm = tlb->mm; > + struct vm_area_struct *vma = walk->vma; > + spinlock_t *ptl; > + pte_t *pte, ptent; > + struct page *page; > + > + split_huge_page_pmd(vma, addr, pmd); > + if (pmd_trans_unstable(pmd)) > + return 0; > + > + pte = pte_offset_map_lock(mm, pmd, addr, &ptl); > + arch_enter_lazy_mmu_mode(); > + for (; addr != end; pte++, addr += PAGE_SIZE) { > + ptent = *pte; > + > + if (!pte_present(ptent)) > + continue; > + > + page = vm_normal_page(vma, addr, ptent); > + if (!page) > + continue; > + > + if (PageSwapCache(page)) { Could you put VM_BUG_ON_PAGE(PageTransCompound(page), page) here? Just in case. > + if (!trylock_page(page)) > + continue; > + > + if (!try_to_free_swap(page)) { > + unlock_page(page); > + continue; > + } > + > + ClearPageDirty(page); > + unlock_page(page); Hm. Do we handle pages shared over fork() here? Souldn't we ignore pages with mapcount > 0? > + } > + > + if (pte_young(ptent) || pte_dirty(ptent)) { > + /* > + * Some of architecture(ex, PPC) don't update TLB > + * with set_pte_at and tlb_remove_tlb_entry so for > + * the portability, remap the pte with old|clean > + * after pte clearing. > + */ > + ptent = ptep_get_and_clear_full(mm, addr, pte, > + tlb->fullmm); > + > + ptent = pte_mkold(ptent); > + ptent = pte_mkclean(ptent); > + set_pte_at(mm, addr, pte, ptent); > + tlb_remove_tlb_entry(tlb, pte, addr); > + } > + } > + > + arch_leave_lazy_mmu_mode(); > + pte_unmap_unlock(pte - 1, ptl); > + cond_resched(); > + return 0; > +} > -- Kirill A. Shutemov -- 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