From nobody Fri Dec 19 02:50:44 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 2EA00C54FB9 for ; Sun, 19 Nov 2023 19:49:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231773AbjKSTtu (ORCPT ); Sun, 19 Nov 2023 14:49:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34474 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231759AbjKSTtT (ORCPT ); Sun, 19 Nov 2023 14:49:19 -0500 Received: from mail-il1-x12b.google.com (mail-il1-x12b.google.com [IPv6:2607:f8b0:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4722AD56 for ; Sun, 19 Nov 2023 11:48:54 -0800 (PST) Received: by mail-il1-x12b.google.com with SMTP id e9e14a558f8ab-3574297c79eso14110605ab.1 for ; Sun, 19 Nov 2023 11:48:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1700423333; x=1701028133; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:reply-to:references :in-reply-to:message-id:date:subject:cc:to:from:from:to:cc:subject :date:message-id:reply-to; bh=9XjpTi/p1jP45iq6KrQ/NXIY9Wo9hQ4YnGSNNoLyAOA=; b=OV7vKBtM8QcyzCdAPX2k3P2b3HevaAp9wu9iHRuPa4/0gMJrOxaOgeg65Tr1JJe1az 6BwJEQF+1Af6fYV3TsevmGa7AH1ExN4MdYI31HH5+ab0NH+IkFs1c7pLpU9XZ9pX3oH3 rpkZ8mxpfjHMDLoBM6FMz2uBdiOjmJyWRkYw1aoCarjmAIVDTvh6z4+0ju77seNKv5YG vV5faKNmy6+it8DLlGQLOVFDPo366HXhDSM9+z1FqOcmluCS116AAO8YpiJ72+Co/pVX Yib44qDni3Y9lU6gKm0XMhBsjCQex8HvlnBJvejLCKAD3g5NdTgJVPGG6f8lSRm0fuXX oxjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700423333; x=1701028133; h=content-transfer-encoding:mime-version:reply-to:references :in-reply-to:message-id:date:subject:cc:to:from:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=9XjpTi/p1jP45iq6KrQ/NXIY9Wo9hQ4YnGSNNoLyAOA=; b=w4wKDOuyZVN8Aj4Yv6ZQNVsiuosFV+IQgxpljsh6psSPUU6TzRBYhKDU07+Z9u6+0t URQzsnwB0Mg4hGwbBICrZXAjgAwJDl7S5owrSqrkdKvWgCfEE5htUQn/0BLwKCmc7s/+ A/EmIYJQhkTiCNeX6U/lrckFcwo3vsPS3a23szzhe0gGoAH7rpxhbzpIwNdKeoNSIxQA l0pvzAzHanw2YxfN3DKWkP/v62mAuDu5AhklBD+Md1mJHBX5efnu5QPKi1+HFf5a7TiZ hJo2H4jFJJxIVcuRtvrmgsH6V6xtPEX9q3VsfYUWlfMGK9KkF2wt0+i4NOK7ldklE6fw IHIg== X-Gm-Message-State: AOJu0YyAZ23s7N/L4ATLeQE0e4DHZ1iN8Lt5mshtLWZIsCt7wRtSNefy +QCdFF2SO1bHJ17c5oPD/ng= X-Google-Smtp-Source: AGHT+IFar6VHQuFklPrfy7vOCI8aqHj+K8WskagViLl4BbbPZwTP7uc43B3VnuoR6l/B/N6mqJ6dzw== X-Received: by 2002:a92:7a06:0:b0:359:5389:c0dc with SMTP id v6-20020a927a06000000b003595389c0dcmr6674915ilc.7.1700423333536; Sun, 19 Nov 2023 11:48:53 -0800 (PST) Received: from KASONG-MB2.tencent.com ([115.171.40.79]) by smtp.gmail.com with ESMTPSA id a6-20020aa78646000000b006cb7feae74fsm1237140pfo.164.2023.11.19.11.48.50 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sun, 19 Nov 2023 11:48:52 -0800 (PST) From: Kairui Song To: linux-mm@kvack.org Cc: Andrew Morton , "Huang, Ying" , David Hildenbrand , Hugh Dickins , Johannes Weiner , Matthew Wilcox , Michal Hocko , linux-kernel@vger.kernel.org, Kairui Song Subject: [PATCH 16/24] mm/swap: reduce scope of get_swap_device in swapin path Date: Mon, 20 Nov 2023 03:47:32 +0800 Message-ID: <20231119194740.94101-17-ryncsn@gmail.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231119194740.94101-1-ryncsn@gmail.com> References: <20231119194740.94101-1-ryncsn@gmail.com> Reply-To: Kairui Song MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Kairui Song Move get_swap_device into swapin_readahead, simplify the code and prepare for follow up commits. For the later part in do_swap_page, using swp_swap_info directly is fine since in that context, the swap device is pinned by swapcache reference. Signed-off-by: Kairui Song --- mm/memory.c | 16 ++++------------ mm/swap_state.c | 8 ++++++-- mm/swapfile.c | 4 +++- 3 files changed, 13 insertions(+), 15 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 22af9f3e8c75..e399b37ef395 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3789,7 +3789,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) struct folio *swapcache =3D NULL, *folio =3D NULL; enum swap_cache_result cache_result; struct page *page; - struct swap_info_struct *si =3D NULL; rmap_t rmap_flags =3D RMAP_NONE; bool exclusive =3D false; swp_entry_t entry; @@ -3845,14 +3844,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) goto out; } =20 - /* Prevent swapoff from happening to us. */ - si =3D get_swap_device(entry); - if (unlikely(!si)) - goto out; - page =3D swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, vmf, &cache_result); - if (page) { + if (PTR_ERR(page) =3D=3D -EBUSY) { + goto out; + } else if (page) { folio =3D page_folio(page); if (cache_result !=3D SWAP_CACHE_HIT) { /* Had to read the page from swap area: Major fault */ @@ -3964,7 +3960,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) */ exclusive =3D true; } else if (exclusive && folio_test_writeback(folio) && - data_race(si->flags & SWP_STABLE_WRITES)) { + (swp_swap_info(entry)->flags & SWP_STABLE_WRITES)) { /* * This is tricky: not all swap backends support * concurrent page modifications while under writeback. @@ -4068,8 +4064,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) if (vmf->pte) pte_unmap_unlock(vmf->pte, vmf->ptl); out: - if (si) - put_swap_device(si); return ret; out_nomap: if (vmf->pte) @@ -4082,8 +4076,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) folio_unlock(swapcache); folio_put(swapcache); } - if (si) - put_swap_device(si); return ret; } =20 diff --git a/mm/swap_state.c b/mm/swap_state.c index 51de2a0412df..ff8a166603d0 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -922,6 +922,11 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t= gfp_mask, struct page *page; pgoff_t ilx; =20 + /* Prevent swapoff from happening to us */ + si =3D get_swap_device(entry); + if (unlikely(!si)) + return ERR_PTR(-EBUSY); + folio =3D swap_cache_get_folio(entry, vmf, &shadow); if (folio) { page =3D folio_file_page(folio, swp_offset(entry)); @@ -929,7 +934,6 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t = gfp_mask, goto done; } =20 - si =3D swp_swap_info(entry); mpol =3D get_vma_policy(vmf->vma, vmf->address, 0, &ilx); if (swap_use_no_readahead(si, swp_offset(entry))) { page =3D swapin_no_readahead(entry, gfp_mask, mpol, ilx, vmf->vma->vm_mm= ); @@ -944,8 +948,8 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t = gfp_mask, cache_result =3D SWAP_CACHE_MISS; } mpol_cond_put(mpol); - done: + put_swap_device(si); if (result) *result =3D cache_result; =20 diff --git a/mm/swapfile.c b/mm/swapfile.c index b6d57fff5e21..925ad92486a4 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1857,7 +1857,9 @@ static int unuse_pte_range(struct vm_area_struct *vma= , pmd_t *pmd, pte =3D NULL; page =3D swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, &vmf, NULL); - if (page) + if (IS_ERR(page)) + return PTR_ERR(page); + else if (page) folio =3D page_folio(page); if (!folio) { /* --=20 2.42.0