From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 46F84158524 for ; Thu, 16 Jan 2025 05:44:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737006255; cv=none; b=YPrVkYCXSUucv2dOXzuZ5mGxZIUHieDUlGMwHyYW7jQYkIkstYQs4n0dY60hBWbCqsfEGXMXzXpj2kXq5Xuh/9Fsy1H+1NOJ7wmThYywzjx7vX+6TTohAhP8lUXMjTNHYlwIDHnHUCglqoLfrEpI4M+D4c4xwPdn0D29IqKRYiM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737006255; c=relaxed/simple; bh=OHsXUCJlPYuFdPtc7gwZC+y804qz97TIM8DGMp81dPU=; h=Date:To:From:Subject:Message-Id; b=brY/0njXpV4foWczp1sFPXfP9NCNBScDbFYAySMXN8TGE4a+FWZp0EypFObHYzJQxiUFsdmtRydoY66gX9tmG0iPIBIFRB4pZ7m4KavsH8oDEMSYQ/1b5bJE4B0rWH0PHTYkOFDpRGIXOlCPY+0iK2EM91TudBa3gOO7gl3lRrU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=TTVNGVQU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="TTVNGVQU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC78FC4CED6; Thu, 16 Jan 2025 05:44:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1737006254; bh=OHsXUCJlPYuFdPtc7gwZC+y804qz97TIM8DGMp81dPU=; h=Date:To:From:Subject:From; b=TTVNGVQU+wUDsyWY9Mo157ah6b1QXDO1bYkFy72AgHCmMiWgMYX0cAoQyh/kZ3VSh mrQvHhPrDyVaUGPv2+pzheaJSAX0vPw33Te4dA47tMf22WKCytukYt15AgvmaBkCDX 2xCdRCL0IpglO8zLES+Pf+1pt77+6+BR8hogZJDM= Date: Wed, 15 Jan 2025 21:44:14 -0800 To: mm-commits@vger.kernel.org,yosryahmed@google.com,ying.huang@linux.alibaba.com,v-songbaohua@oppo.com,ryan.roberts@arm.com,nphamcs@gmail.com,kaleshsingh@google.com,hughd@google.com,hannes@cmpxchg.org,chrisl@kernel.org,bhe@redhat.com,kasong@tencent.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-swap-use-an-enum-to-define-all-cluster-flags-and-wrap-flags-changes.patch removed from -mm tree Message-Id: <20250116054414.BC78FC4CED6@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm, swap: use an enum to define all cluster flags and wrap flags changes has been removed from the -mm tree. Its filename was mm-swap-use-an-enum-to-define-all-cluster-flags-and-wrap-flags-changes.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Kairui Song Subject: mm, swap: use an enum to define all cluster flags and wrap flags changes Date: Tue, 14 Jan 2025 01:57:27 +0800 Currently, we are only using flags to indicate which list the cluster is on. Using one bit for each list type might be a waste, as the list type grows, we will consume too many bits. Additionally, the current mixed usage of '&' and '==' is a bit confusing. Make it clean by using an enum to define all possible cluster statuses. Only an off-list cluster will have the NONE (0) flag. And use a wrapper to annotate and sanitize all flag settings and list movements. Link: https://lkml.kernel.org/r/20250113175732.48099-9-ryncsn@gmail.com Signed-off-by: Kairui Song Suggested-by: Chris Li Cc: Baoquan He Cc: Barry Song Cc: "Huang, Ying" Cc: Hugh Dickens Cc: Johannes Weiner Cc: Kalesh Singh Cc: Nhat Pham Cc: Ryan Roberts Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- include/linux/swap.h | 17 +++++++-- mm/swapfile.c | 76 +++++++++++++++++++++-------------------- 2 files changed, 53 insertions(+), 40 deletions(-) --- a/include/linux/swap.h~mm-swap-use-an-enum-to-define-all-cluster-flags-and-wrap-flags-changes +++ a/include/linux/swap.h @@ -256,10 +256,19 @@ struct swap_cluster_info { u8 order; struct list_head list; }; -#define CLUSTER_FLAG_FREE 1 /* This cluster is free */ -#define CLUSTER_FLAG_NONFULL 2 /* This cluster is on nonfull list */ -#define CLUSTER_FLAG_FRAG 4 /* This cluster is on nonfull list */ -#define CLUSTER_FLAG_FULL 8 /* This cluster is on full list */ + +/* All on-list cluster must have a non-zero flag. */ +enum swap_cluster_flags { + CLUSTER_FLAG_NONE = 0, /* For temporary off-list cluster */ + CLUSTER_FLAG_FREE, + CLUSTER_FLAG_NONFULL, + CLUSTER_FLAG_FRAG, + /* Clusters with flags above are allocatable */ + CLUSTER_FLAG_USABLE = CLUSTER_FLAG_FRAG, + CLUSTER_FLAG_FULL, + CLUSTER_FLAG_DISCARD, + CLUSTER_FLAG_MAX, +}; /* * The first page in the swap file is the swap header, which is always marked --- a/mm/swapfile.c~mm-swap-use-an-enum-to-define-all-cluster-flags-and-wrap-flags-changes +++ a/mm/swapfile.c @@ -403,7 +403,7 @@ static void discard_swap_cluster(struct static inline bool cluster_is_free(struct swap_cluster_info *info) { - return info->flags & CLUSTER_FLAG_FREE; + return info->flags == CLUSTER_FLAG_FREE; } static inline unsigned int cluster_index(struct swap_info_struct *si, @@ -434,6 +434,28 @@ static inline void unlock_cluster(struct spin_unlock(&ci->lock); } +static void move_cluster(struct swap_info_struct *si, + struct swap_cluster_info *ci, struct list_head *list, + enum swap_cluster_flags new_flags) +{ + VM_WARN_ON(ci->flags == new_flags); + + BUILD_BUG_ON(1 << sizeof(ci->flags) * BITS_PER_BYTE < CLUSTER_FLAG_MAX); + + if (ci->flags == CLUSTER_FLAG_NONE) { + list_add_tail(&ci->list, list); + } else { + if (ci->flags == CLUSTER_FLAG_FRAG) { + VM_WARN_ON(!si->frag_cluster_nr[ci->order]); + si->frag_cluster_nr[ci->order]--; + } + list_move_tail(&ci->list, list); + } + ci->flags = new_flags; + if (new_flags == CLUSTER_FLAG_FRAG) + si->frag_cluster_nr[ci->order]++; +} + /* Add a cluster to discard list and schedule it to do discard */ static void swap_cluster_schedule_discard(struct swap_info_struct *si, struct swap_cluster_info *ci) @@ -447,10 +469,8 @@ static void swap_cluster_schedule_discar */ memset(si->swap_map + idx * SWAPFILE_CLUSTER, SWAP_MAP_BAD, SWAPFILE_CLUSTER); - - VM_BUG_ON(ci->flags & CLUSTER_FLAG_FREE); - list_move_tail(&ci->list, &si->discard_clusters); - ci->flags = 0; + VM_BUG_ON(ci->flags == CLUSTER_FLAG_FREE); + move_cluster(si, ci, &si->discard_clusters, CLUSTER_FLAG_DISCARD); schedule_work(&si->discard_work); } @@ -458,12 +478,7 @@ static void __free_cluster(struct swap_i { lockdep_assert_held(&si->lock); lockdep_assert_held(&ci->lock); - - if (ci->flags) - list_move_tail(&ci->list, &si->free_clusters); - else - list_add_tail(&ci->list, &si->free_clusters); - ci->flags = CLUSTER_FLAG_FREE; + move_cluster(si, ci, &si->free_clusters, CLUSTER_FLAG_FREE); ci->order = 0; } @@ -479,6 +494,8 @@ static void swap_do_scheduled_discard(st while (!list_empty(&si->discard_clusters)) { ci = list_first_entry(&si->discard_clusters, struct swap_cluster_info, list); list_del(&ci->list); + /* Must clear flag when taking a cluster off-list */ + ci->flags = CLUSTER_FLAG_NONE; idx = cluster_index(si, ci); spin_unlock(&si->lock); @@ -519,9 +536,6 @@ static void free_cluster(struct swap_inf lockdep_assert_held(&si->lock); lockdep_assert_held(&ci->lock); - if (ci->flags & CLUSTER_FLAG_FRAG) - si->frag_cluster_nr[ci->order]--; - /* * If the swap is discardable, prepare discard the cluster * instead of free it immediately. The cluster will be freed @@ -573,13 +587,9 @@ static void dec_cluster_info_page(struct return; } - if (!(ci->flags & CLUSTER_FLAG_NONFULL)) { - VM_BUG_ON(ci->flags & CLUSTER_FLAG_FREE); - if (ci->flags & CLUSTER_FLAG_FRAG) - si->frag_cluster_nr[ci->order]--; - list_move_tail(&ci->list, &si->nonfull_clusters[ci->order]); - ci->flags = CLUSTER_FLAG_NONFULL; - } + if (ci->flags != CLUSTER_FLAG_NONFULL) + move_cluster(si, ci, &si->nonfull_clusters[ci->order], + CLUSTER_FLAG_NONFULL); } static bool cluster_reclaim_range(struct swap_info_struct *si, @@ -663,11 +673,13 @@ static bool cluster_alloc_range(struct s if (!(si->flags & SWP_WRITEOK)) return false; + VM_BUG_ON(ci->flags == CLUSTER_FLAG_NONE); + VM_BUG_ON(ci->flags > CLUSTER_FLAG_USABLE); + if (cluster_is_free(ci)) { - if (nr_pages < SWAPFILE_CLUSTER) { - list_move_tail(&ci->list, &si->nonfull_clusters[order]); - ci->flags = CLUSTER_FLAG_NONFULL; - } + if (nr_pages < SWAPFILE_CLUSTER) + move_cluster(si, ci, &si->nonfull_clusters[order], + CLUSTER_FLAG_NONFULL); ci->order = order; } @@ -675,14 +687,8 @@ static bool cluster_alloc_range(struct s swap_range_alloc(si, nr_pages); ci->count += nr_pages; - if (ci->count == SWAPFILE_CLUSTER) { - VM_BUG_ON(!(ci->flags & - (CLUSTER_FLAG_FREE | CLUSTER_FLAG_NONFULL | CLUSTER_FLAG_FRAG))); - if (ci->flags & CLUSTER_FLAG_FRAG) - si->frag_cluster_nr[ci->order]--; - list_move_tail(&ci->list, &si->full_clusters); - ci->flags = CLUSTER_FLAG_FULL; - } + if (ci->count == SWAPFILE_CLUSTER) + move_cluster(si, ci, &si->full_clusters, CLUSTER_FLAG_FULL); return true; } @@ -821,9 +827,7 @@ new_cluster: while (!list_empty(&si->nonfull_clusters[order])) { ci = list_first_entry(&si->nonfull_clusters[order], struct swap_cluster_info, list); - list_move_tail(&ci->list, &si->frag_clusters[order]); - ci->flags = CLUSTER_FLAG_FRAG; - si->frag_cluster_nr[order]++; + move_cluster(si, ci, &si->frag_clusters[order], CLUSTER_FLAG_FRAG); offset = alloc_swap_scan_cluster(si, cluster_offset(si, ci), &found, order, usage); frags++; _ Patches currently in -mm which might be from kasong@tencent.com are