From nobody Fri Dec 26 19:24:23 2025 Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91BA116400 for ; Tue, 2 Jan 2024 17:54:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="d1IUZ15P" Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-1d4a980fdedso18617695ad.1 for ; Tue, 02 Jan 2024 09:54:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1704218050; x=1704822850; 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=nlZ0fg6NatnLjyD4rpGx2P4cih5u8+SQurmVS5ry9aQ=; b=d1IUZ15PrvfH4sIZWM9dh5/ZjjJBNUeQsauTWJAQM5A+DYZJd5s5VqrNTVY22eHj69 OHXcyuCRhAyOyohsdngiCNsS669xt19+3lR/4yDdTaDZ0JZFnzKqEDXY7xROrA1+hg3l Httm3BHwRdTYwjDo2vOC0XJP7FMi+eofHeip5z0tV4iqZmYoU/ZlA/ocm/btUBGxzh6s mz03Ru6FdAF+KhcKMU/ODQJ62D/Zu8PJfYByMssaFtWVjGLa/DmKTpLO0O6fvFF40Bga /a9RSwC5cytBGxYrDeK5sCWygfcytMB4LbF2SUeA+1IESGhBTKQDpoEPqtlmuA5Ho6A6 GnyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704218050; x=1704822850; 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=nlZ0fg6NatnLjyD4rpGx2P4cih5u8+SQurmVS5ry9aQ=; b=HhOKJf+gcUFiEshMcN+bH4l0624PtueaDGgI2QOfUAhXAgpI1himqOVFRIeC5RysH2 jDq6mednBOsBbdSxSNzOYnK59iWYqYeGv+wP03lb0vaEKjEWN8oQ0xIbAi/nurntyl1j MCrfvwu6nOB068pc/nLVHIiH7zliO6g2mQaHzaFd6DESdy3pcoJVkU1VddcO2mCxv5Cp F9RFTpMqiMigw2E5AjkyFjRG1Zlm81uVztP+LvQf3UwPa0R9CfSC5vG33zlpkNNp8muK EpxUQdOxiEmsPyr8+/uoYGBQf6hojRwBwJU3QPQ5foz8NmE7s9j9ynsJTpdXFIGCbBgb FoUQ== X-Gm-Message-State: AOJu0Yx64XzP/IY4EvtWiouXHb0uqBji4dOmom4qUtDpuTjNfTP5Ec79 ekO6I8w5sZooJCHAGwAoI2kRvH7cy0jtdaUN X-Google-Smtp-Source: AGHT+IHg3EaXPsfJ3BsQyYM+9C4NVV8c46gR3f+IfIC1eTcpnGbk9EIEm5Ji/30WqG1cQYmyBx9asQ== X-Received: by 2002:a17:903:41d1:b0:1d4:3b72:b294 with SMTP id u17-20020a17090341d100b001d43b72b294mr20703980ple.88.1704218049886; Tue, 02 Jan 2024 09:54:09 -0800 (PST) Received: from KASONG-MB2.tencent.com ([115.171.41.9]) by smtp.gmail.com with ESMTPSA id be10-20020a170902aa0a00b001d3c3d486bfsm22151969plb.163.2024.01.02.09.54.06 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Tue, 02 Jan 2024 09:54:09 -0800 (PST) From: Kairui Song To: linux-mm@kvack.org Cc: Andrew Morton , Chris Li , "Huang, Ying" , Hugh Dickins , Johannes Weiner , Matthew Wilcox , Michal Hocko , Yosry Ahmed , David Hildenbrand , linux-kernel@vger.kernel.org, Kairui Song Subject: [PATCH v2 5/9] mm/swap: introduce swapin_entry for unified readahead policy Date: Wed, 3 Jan 2024 01:53:34 +0800 Message-ID: <20240102175338.62012-6-ryncsn@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240102175338.62012-1-ryncsn@gmail.com> References: <20240102175338.62012-1-ryncsn@gmail.com> Reply-To: Kairui Song Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Kairui Song Introduce swapin_entry which merges swapin_readahead and swapin_direct making it the main entry for swapin pages, and use a unified swapin policy. This commit makes swapoff make use of this new helper and now swapping off a 10G ZRAM (lzo-rle) is faster since readahead is skipped. Before: time swapoff /dev/zram0 real 0m12.337s user 0m0.001s sys 0m12.329s After: time swapoff /dev/zram0 real 0m9.728s user 0m0.001s sys 0m9.719s Signed-off-by: Kairui Song --- mm/memory.c | 21 +++++++-------------- mm/swap.h | 16 ++++------------ mm/swap_state.c | 49 +++++++++++++++++++++++++++++++++---------------- mm/swapfile.c | 7 ++----- 4 files changed, 46 insertions(+), 47 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 0165c8cad489..b56254a875f8 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3801,6 +3801,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) rmap_t rmap_flags =3D RMAP_NONE; bool exclusive =3D false; swp_entry_t entry; + bool swapcached; pte_t pte; vm_fault_t ret =3D 0; =20 @@ -3864,21 +3865,13 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) swapcache =3D folio; =20 if (!folio) { - if (data_race(si->flags & SWP_SYNCHRONOUS_IO) && - __swap_count(entry) =3D=3D 1) { - /* skip swapcache and readahead */ - folio =3D swapin_direct(entry, GFP_HIGHUSER_MOVABLE, vmf); - if (folio) - page =3D &folio->page; + folio =3D swapin_entry(entry, GFP_HIGHUSER_MOVABLE, + vmf, &swapcached); + if (folio) { + page =3D folio_file_page(folio, swp_offset(entry)); + if (swapcached) + swapcache =3D folio; } else { - page =3D swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, - vmf); - if (page) - folio =3D page_folio(page); - swapcache =3D folio; - } - - if (!folio) { /* * Back out if somebody else faulted in this pte * while we released the pte lock. diff --git a/mm/swap.h b/mm/swap.h index 83eab7b67e77..502a2801f817 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -54,10 +54,8 @@ struct folio *__read_swap_cache_async(swp_entry_t entry,= gfp_t gfp_flags, bool skip_if_exists); struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, struct mempolicy *mpol, pgoff_t ilx); -struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, - struct vm_fault *vmf); -struct folio *swapin_direct(swp_entry_t entry, gfp_t flag, - struct vm_fault *vmf); +struct folio *swapin_entry(swp_entry_t entry, gfp_t flag, + struct vm_fault *vmf, bool *swapcached); =20 static inline unsigned int folio_swap_flags(struct folio *folio) { @@ -88,14 +86,8 @@ static inline struct folio *swap_cluster_readahead(swp_e= ntry_t entry, return NULL; } =20 -struct folio *swapin_direct(swp_entry_t entry, gfp_t flag, - struct vm_fault *vmf) -{ - return NULL; -} - -static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mas= k, - struct vm_fault *vmf) +static inline struct folio *swapin_entry(swp_entry_t swp, gfp_t gfp_mask, + struct vm_fault *vmf, bool *swapcached) { return NULL; } diff --git a/mm/swap_state.c b/mm/swap_state.c index d39c5369da21..66ff187aa5d3 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -316,6 +316,11 @@ void free_pages_and_swap_cache(struct encoded_page **p= ages, int nr) release_pages(pages, nr); } =20 +static inline bool swap_use_no_readahead(struct swap_info_struct *si, swp_= entry_t entry) +{ + return data_race(si->flags & SWP_SYNCHRONOUS_IO) && __swap_count(entry) = =3D=3D 1; +} + static inline bool swap_use_vma_readahead(void) { return READ_ONCE(enable_vma_readahead) && !atomic_read(&nr_rotate_swap); @@ -870,8 +875,8 @@ static struct folio *swap_vma_readahead(swp_entry_t tar= g_entry, gfp_t gfp_mask, * Returns the struct folio for entry and addr after the swap entry is read * in. */ -struct folio *swapin_direct(swp_entry_t entry, gfp_t gfp_mask, - struct vm_fault *vmf) +static struct folio *swapin_direct(swp_entry_t entry, gfp_t gfp_mask, + struct vm_fault *vmf) { struct vm_area_struct *vma =3D vmf->vma; struct folio *folio; @@ -908,33 +913,45 @@ struct folio *swapin_direct(swp_entry_t entry, gfp_t = gfp_mask, } =20 /** - * swapin_readahead - swap in pages in hope we need them soon + * swapin_entry - swap in a page from swap entry * @entry: swap entry of this memory * @gfp_mask: memory allocation flags * @vmf: fault information + * @swapcached: pointer to a bool used as indicator if the + * page is swapped in through swapcache. * * Returns the struct page for entry and addr, after queueing swapin. * - * It's a main entry function for swap readahead. By the configuration, + * It's a main entry function for swap in. By the configuration, * it will read ahead blocks by cluster-based(ie, physical disk based) - * or vma-based(ie, virtual address based on faulty address) readahead. + * or vma-based(ie, virtual address based on faulty address) readahead, + * or skip the readahead (ie, ramdisk based swap device). */ -struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, - struct vm_fault *vmf) +struct folio *swapin_entry(swp_entry_t entry, gfp_t gfp_mask, + struct vm_fault *vmf, bool *swapcached) { struct mempolicy *mpol; - pgoff_t ilx; struct folio *folio; + pgoff_t ilx; + bool cached; =20 - mpol =3D get_vma_policy(vmf->vma, vmf->address, 0, &ilx); - folio =3D swap_use_vma_readahead() ? - swap_vma_readahead(entry, gfp_mask, mpol, ilx, vmf) : - swap_cluster_readahead(entry, gfp_mask, mpol, ilx); - mpol_cond_put(mpol); + if (swap_use_no_readahead(swp_swap_info(entry), entry)) { + folio =3D swapin_direct(entry, gfp_mask, vmf); + cached =3D false; + } else { + mpol =3D get_vma_policy(vmf->vma, vmf->address, 0, &ilx); + if (swap_use_vma_readahead()) + folio =3D swap_vma_readahead(entry, gfp_mask, mpol, ilx, vmf); + else + folio =3D swap_cluster_readahead(entry, gfp_mask, mpol, ilx); + mpol_cond_put(mpol); + cached =3D true; + } =20 - if (!folio) - return NULL; - return folio_file_page(folio, swp_offset(entry)); + if (swapcached) + *swapcached =3D cached; + + return folio; } =20 #ifdef CONFIG_SYSFS diff --git a/mm/swapfile.c b/mm/swapfile.c index f7271504aa0a..ce4e6c10dce7 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1866,7 +1866,6 @@ static int unuse_pte_range(struct vm_area_struct *vma= , pmd_t *pmd, =20 folio =3D swap_cache_get_folio(entry, vma, addr); if (!folio) { - struct page *page; struct vm_fault vmf =3D { .vma =3D vma, .address =3D addr, @@ -1874,10 +1873,8 @@ static int unuse_pte_range(struct vm_area_struct *vm= a, pmd_t *pmd, .pmd =3D pmd, }; =20 - page =3D swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, - &vmf); - if (page) - folio =3D page_folio(page); + folio =3D swapin_entry(entry, GFP_HIGHUSER_MOVABLE, + &vmf, NULL); } if (!folio) { /* --=20 2.43.0