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 80DBD5B211 for ; Tue, 25 Feb 2025 03:26:44 +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=1740454004; cv=none; b=EilTNQQt+vKxFr8w/bcjnPKMGECNVbb3rLCSksxOoorurvk9i6RhSjMageKwtDpHqZEVUoqecoL/f4FmuqF9Htk0rHBjQrMbCngcjJemObO74jJ27zy7LErtLqYeGytZrUvlDzyOutXNdCr3Xko+8BgSAWjUxuaaae5Kju7vKcI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740454004; c=relaxed/simple; bh=SRhpFn1onKZU4ToACbcIeh0LKRUX3pAEkxq2tR0sreY=; h=Date:To:From:Subject:Message-Id; b=Cq43pKt5pF+UbZhGN1Dzp1sbQqbsxDDCG/tZkzsg3ClLmIn399ToGe5VmZIcLgQ7TcYjSuQLZ+42E6jO2Gr6BQAu2yQidFb8N4k21TdOZrKokI34t5JQPK8YxemklZI0pVt0IxalmivpUX+iTY+CZNqvs/+gvC0VwQ3ENSXrepE= 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=oxI/2fsp; 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="oxI/2fsp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E6BE8C4CED6; Tue, 25 Feb 2025 03:26:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1740454004; bh=SRhpFn1onKZU4ToACbcIeh0LKRUX3pAEkxq2tR0sreY=; h=Date:To:From:Subject:From; b=oxI/2fsp8ooKsfBwfp2U7LVpmtXwiWc6YKmMtXLVdXlPTTOKn9rO8uZfsalcR4GI3 aEiv/dHzChI3NxwtUl7yPlCYgS86m5xW+snhV9MH+zAafy+hqZHQVBGsD7r6uFSqTd nu2rYY/KqEnB8NFacf4kq8XSTF4EF3GeDYEhx5l8= Date: Mon, 24 Feb 2025 19:26:43 -0800 To: mm-commits@vger.kernel.org,yosryahmed@google.com,ying.huang@linux.alibaba.com,willy@infradead.org,v-songbaohua@oppo.com,nphamcs@gmail.com,kaleshsingh@google.com,hughd@google.com,hannes@cmpxchg.org,chrisl@kernel.org,bhe@redhat.com,baolin.wang@linux.alibaba.com,kasong@tencent.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-swap-dont-update-the-counter-up-front.patch added to mm-unstable branch Message-Id: <20250225032643.E6BE8C4CED6@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm, swap: don't update the counter up-front has been added to the -mm mm-unstable branch. Its filename is mm-swap-dont-update-the-counter-up-front.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swap-dont-update-the-counter-up-front.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Kairui Song Subject: mm, swap: don't update the counter up-front Date: Tue, 25 Feb 2025 02:02:09 +0800 The counter update before allocation design was useful to avoid unnecessary scan when device is full, so it will abort early if the counter indicates the device is full. But that is an uncommon case, and now scanning of a full device is very fast, so the up-front update is not helpful any more. Remove it and simplify the slot allocation logic. Link: https://lkml.kernel.org/r/20250224180212.22802-5-ryncsn@gmail.com Signed-off-by: Kairui Song Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Chris Li Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Johannes Weiner Cc: Kalesh Singh Cc: Matthew Wilcow (Oracle) Cc: Nhat Pham Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- mm/swapfile.c | 18 ++---------------- 1 file changed, 2 insertions(+), 16 deletions(-) --- a/mm/swapfile.c~mm-swap-dont-update-the-counter-up-front +++ a/mm/swapfile.c @@ -1201,22 +1201,10 @@ int get_swap_pages(int n_goal, swp_entry int order = swap_entry_order(entry_order); unsigned long size = 1 << order; struct swap_info_struct *si, *next; - long avail_pgs; int n_ret = 0; int node; spin_lock(&swap_avail_lock); - - avail_pgs = atomic_long_read(&nr_swap_pages) / size; - if (avail_pgs <= 0) { - spin_unlock(&swap_avail_lock); - goto noswap; - } - - n_goal = min3((long)n_goal, (long)SWAP_BATCH, avail_pgs); - - atomic_long_sub(n_goal * size, &nr_swap_pages); - start_over: node = numa_node_id(); plist_for_each_entry_safe(si, next, &swap_avail_heads[node], avail_lists[node]) { @@ -1250,10 +1238,8 @@ start_over: spin_unlock(&swap_avail_lock); check_out: - if (n_ret < n_goal) - atomic_long_add((long)(n_goal - n_ret) * size, - &nr_swap_pages); -noswap: + atomic_long_sub(n_ret * size, &nr_swap_pages); + return n_ret; } _ Patches currently in -mm which might be from kasong@tencent.com are mm-swap-avoid-reclaiming-irrelevant-swap-cache.patch mm-swap-drop-the-flag-ttrs_direct.patch mm-swap-avoid-redundant-swap-device-pinning.patch mm-swap-dont-update-the-counter-up-front.patch mm-swap-use-percpu-cluster-as-allocation-fast-path.patch mm-swap-remove-swap-slot-cache.patch mm-swap-simplify-folio-swap-allocation.patch