From nobody Tue Sep 16 09:01:24 2025 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 517F0C3DA7D for ; Thu, 5 Jan 2023 10:22:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232562AbjAEKWI (ORCPT ); Thu, 5 Jan 2023 05:22:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231841AbjAEKUA (ORCPT ); Thu, 5 Jan 2023 05:20:00 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6956D559FA for ; Thu, 5 Jan 2023 02:19:31 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id t13-20020a056902018d00b0074747131938so36503973ybh.12 for ; Thu, 05 Jan 2023 02:19:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=9Yt8Zfl8fNE6CjUoa2m2ZbJ28GLtsXtxPk8weKgz6Sk=; b=mmJynU/TU9vgbAWdVBnooR6qbWy6e6Xt4HjkahKPBivEshc97MtogxTwIBRYXaYqJ0 fSpmPH7oyypf8QtZl1TBck6C8Qnc5vP3vXChtZzIua5/HPzB+uT2N0El75+vpSdXgb3I fXUucvYApqmIOdNMwmWBYNiybAbob8pq547IG5xhW67a2+7RxSBPQsKdkno0G9NfjnHR vThJc94sL2B5jTo0R162NfJZTasyE6NQSOqGcbgqMDv7BN8cJUhlAVO1ikA07733qw6v J0FL1bdTenfsSmm7z4ZB7CRnQWtuNtJNF7SWWWGOq6wzEvgYIHYppRVKiHaPtU8vk09q t6pA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=9Yt8Zfl8fNE6CjUoa2m2ZbJ28GLtsXtxPk8weKgz6Sk=; b=cXo5JUEh4o8GWtFh0oryi0iMbw+nEYMwepqaRK37DFNyHS3xixrNsxy4GnAhhfESbO 9Cc+Cq3cT/mYzX2t9pxUg03ukXJ8lpJgCRRqcW2Yt0P4lj5u2wFhx+DvB46SKjN4/JVh wI5wlL7udYE7HTWNkeMVcA/r9zlqCdwAGo5W7XqMlM/7LJRDbRyMjzjVjM4Nv8flAxYe Tl8FDnvyy0Dw/NzR8+6iK+n9F9xdJq3gaIlBS9FxAayJ3WDmnmFrYcyJEg0BWHETQT5P npn259uRI1jWaOJ1o6NGg1SnMWgcMbWkFOiUPiF1hMA83mfX0URmJCGaQteSQUy7q9zz D0Jw== X-Gm-Message-State: AFqh2ko+AcwQSKmLOxIONL3y7Ua3XET/wdCAa6h/3QWWjeX7nRkD+wsj zK3FLGeOLD6lWvNihQTecY0ehcRN0CF9cWL0 X-Google-Smtp-Source: AMrXdXuVcGaIehPK3ggZHRYdepJOSa1ZuL0a2MndWjzlHZKir2rPDwMHed4R9zmgcZPJJPozNStrKME793+njzVf X-Received: from jthoughton.c.googlers.com ([fda3:e722:ac3:cc00:14:4d90:c0a8:2a4f]) (user=jthoughton job=sendgmr) by 2002:a25:5056:0:b0:7b6:2b8f:f2c0 with SMTP id e83-20020a255056000000b007b62b8ff2c0mr25432ybb.46.1672913971225; Thu, 05 Jan 2023 02:19:31 -0800 (PST) Date: Thu, 5 Jan 2023 10:18:23 +0000 In-Reply-To: <20230105101844.1893104-1-jthoughton@google.com> Mime-Version: 1.0 References: <20230105101844.1893104-1-jthoughton@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20230105101844.1893104-26-jthoughton@google.com> Subject: [PATCH 25/46] hugetlb: update page_vma_mapped to do high-granularity walks From: James Houghton To: Mike Kravetz , Muchun Song , Peter Xu Cc: David Hildenbrand , David Rientjes , Axel Rasmussen , Mina Almasry , "Zach O'Keefe" , Manish Mishra , Naoya Horiguchi , "Dr . David Alan Gilbert" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Baolin Wang , Miaohe Lin , Yang Shi , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, James Houghton Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Update the HugeTLB logic to look a lot more like the PTE-mapped THP logic. When a user calls us in a loop, we will update pvmw->address to walk to each page table entry that could possibly map the hugepage containing pvmw->pfn. Make use of the new pte_order so callers know what size PTE they're getting. The !pte failure case is changed to call not_found() instead of just returning false. This should be a no-op, but if somehow the hstate-level PTE were deallocated between iterations, not_found() should be called to drop locks. Signed-off-by: James Houghton --- mm/page_vma_mapped.c | 59 +++++++++++++++++++++++++++++++------------- 1 file changed, 42 insertions(+), 17 deletions(-) diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 08295b122ad6..03e8a4987272 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -133,7 +133,8 @@ static void step_forward(struct page_vma_mapped_walk *p= vmw, unsigned long size) * * Returns true if the page is mapped in the vma. @pvmw->pmd and @pvmw->pt= e point * to relevant page table entries. @pvmw->ptl is locked. @pvmw->address is - * adjusted if needed (for PTE-mapped THPs). + * adjusted if needed (for PTE-mapped THPs and high-granularity-mapped Hug= eTLB + * pages). * * If @pvmw->pmd is set but @pvmw->pte is not, you have found PMD-mapped p= age * (usually THP). For PTE-mapped THP, you should run page_vma_mapped_walk(= ) in @@ -165,23 +166,47 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk= *pvmw) =20 if (unlikely(is_vm_hugetlb_page(vma))) { struct hstate *hstate =3D hstate_vma(vma); - unsigned long size =3D huge_page_size(hstate); - /* The only possible mapping was handled on last iteration */ - if (pvmw->pte) - return not_found(pvmw); - /* - * All callers that get here will already hold the - * i_mmap_rwsem. Therefore, no additional locks need to be - * taken before calling hugetlb_walk(). - */ - pvmw->pte =3D hugetlb_walk(vma, pvmw->address, size); - if (!pvmw->pte) - return false; + struct hugetlb_pte hpte; + pte_t pteval; + + end =3D (pvmw->address & huge_page_mask(hstate)) + + huge_page_size(hstate); + + do { + if (pvmw->pte) { + if (pvmw->ptl) + spin_unlock(pvmw->ptl); + pvmw->ptl =3D NULL; + pvmw->address +=3D PAGE_SIZE << pvmw->pte_order; + if (pvmw->address >=3D end) + return not_found(pvmw); + } =20 - pvmw->pte_order =3D huge_page_order(hstate); - pvmw->ptl =3D huge_pte_lock(hstate, mm, pvmw->pte); - if (!check_pte(pvmw)) - return not_found(pvmw); + /* + * All callers that get here will already hold the + * i_mmap_rwsem. Therefore, no additional locks need to + * be taken before calling hugetlb_walk(). + */ + if (hugetlb_full_walk(&hpte, vma, pvmw->address)) + return not_found(pvmw); + +retry: + pvmw->pte =3D hpte.ptep; + pvmw->pte_order =3D hpte.shift - PAGE_SHIFT; + pvmw->ptl =3D hugetlb_pte_lock(&hpte); + pteval =3D huge_ptep_get(hpte.ptep); + if (pte_present(pteval) && !hugetlb_pte_present_leaf( + &hpte, pteval)) { + /* + * Someone split from under us, so keep + * walking. + */ + spin_unlock(pvmw->ptl); + hugetlb_full_walk_continue(&hpte, vma, + pvmw->address); + goto retry; + } + } while (!check_pte(pvmw)); return true; } =20 --=20 2.39.0.314.g84b9a713c41-goog