From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 849C9C001DF for ; Fri, 28 Jul 2023 18:34:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230311AbjG1SeS (ORCPT ); Fri, 28 Jul 2023 14:34:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229782AbjG1SeQ (ORCPT ); Fri, 28 Jul 2023 14:34:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21946423B for ; Fri, 28 Jul 2023 11:34:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B2E15621AD for ; Fri, 28 Jul 2023 18:34:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1DC1C433C8; Fri, 28 Jul 2023 18:34:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1690569253; bh=/ETXr35GlXt0lU8/LQjsLacBjCHt5zwDBcQ0Op7/lFs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=YTsH65jzd0Sqntit8sAw82+9M0LlNChQHLbo/BlV9Dry+yXgUbPL84x5DOBlIIWUe 0yybr65hMII/yjAywfknW/QPYesC8SOU6+XqDz7PCeRev3jPEmqpnJx66bSKtNe3Qz FwNrSadjqZD4xnnjrQxT4bRQYjaxVwEJZ3PxUgSs= Date: Fri, 28 Jul 2023 11:34:12 -0700 From: Andrew Morton To: Yin Fengwei Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, yuzhao@google.com, willy@infradead.org, david@redhat.com, ryan.roberts@arm.com, shy828301@gmail.com, hughd@google.com Subject: Re: [PATCH 1/3] mm: add functions folio_in_range() and folio_within_vma() Message-Id: <20230728113412.65741d2dd23228d0e2c0cb8d@linux-foundation.org> In-Reply-To: <20230728070929.2487065-2-fengwei.yin@intel.com> References: <20230728070929.2487065-1-fengwei.yin@intel.com> <20230728070929.2487065-2-fengwei.yin@intel.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 28 Jul 2023 15:09:27 +0800 Yin Fengwei wrote: > It will be used to check whether the folio is mapped to specific > VMA and whether the mapping address of folio is in the range. > > Also a helper function folio_within_vma() to check whether folio > is in the range of vma based on folio_in_range(). > > ... > > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -585,6 +585,75 @@ extern long faultin_vma_page_range(struct vm_area_struct *vma, > bool write, int *locked); > extern bool mlock_future_ok(struct mm_struct *mm, unsigned long flags, > unsigned long bytes); > + > +/* > + * Check whether the folio is in specific range > + * > + * First, check whether the folio is in the range of vma. > + * Then, check whether the folio is mapped to the range of [start, end]. > + * In the end, check whether the folio is fully mapped to the range. > + * > + * @pte page table pointer will be checked whether the large folio > + * is fully mapped to. Currently, if mremap in the middle of > + * large folio, the large folio could be mapped to to different > + * VMA and address check can't identify this situation. > + */ > +static inline bool > +folio_in_range(struct folio *folio, struct vm_area_struct *vma, > + unsigned long start, unsigned long end, pte_t *pte) > +{ This looks crazily way too large to be inlined? > + pte_t ptent; > + unsigned long i, nr = folio_nr_pages(folio); > + pgoff_t pgoff, addr; > + unsigned long vma_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; > + > + VM_WARN_ON_FOLIO(folio_test_ksm(folio), folio); > + > + if (start < vma->vm_start) > + start = vma->vm_start; > + if (end > vma->vm_end) > + end = vma->vm_end; > + > + pgoff = folio_pgoff(folio); > + /* if folio start address is not in vma range */ > + if (pgoff < vma->vm_pgoff || pgoff > vma->vm_pgoff + vma_pglen) > + return false; > + > + addr = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); > + if (addr < start || end - addr < folio_size(folio)) > + return false; > + > + /* not necessary to check pte for none large folio */ > + if (!folio_test_large(folio)) > + return true; > + > + if (!pte) > + return false; > + > + /* check whether parameter pte is associated with folio */ > + ptent = ptep_get(pte); > + if (pte_none(ptent) || !pte_present(ptent) || > + pte_pfn(ptent) - folio_pfn(folio) >= nr) > + return false; > + > + pte -= pte_pfn(ptent) - folio_pfn(folio); > + for (i = 0; i < nr; i++, pte++) { > + ptent = ptep_get(pte); > + > + if (pte_none(ptent) || !pte_present(ptent) || > + pte_pfn(ptent) - folio_pfn(folio) >= nr) > + return false; > + } > + > + return true; > +} > + > +static inline bool > +folio_within_vma(struct folio *folio, struct vm_area_struct *vma, pte_t *pte) > +{ > + return folio_in_range(folio, vma, vma->vm_start, vma->vm_end, pte); > +} And this doesn't.