From patchwork Fri Feb 2 23:12:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Burkov X-Patchwork-Id: 13543571 Received: from wout4-smtp.messagingengine.com (wout4-smtp.messagingengine.com [64.147.123.20]) (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 ADE2B12F365 for ; Fri, 2 Feb 2024 23:11:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=64.147.123.20 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706915481; cv=none; b=QdeZ5FVjFLkPDv1GktOWT3AAHvw2Xmq5C+NElz4HBiIjMM4tZ46B33lZpgeJSX6uqR7I5DsdIHchOtkMJnNL6tCmDKAU9ACc+AvJ3Y/51Z/eZDmkMTOXcroGQcC5ZvclYJAFicMhO+WZD9cAnEPI4tN1F0oXdgCevyRnvMxVKqo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706915481; c=relaxed/simple; bh=l9YURtbeIUuyNk5PEmNwlwr7hiVMyrTp3TPGK5Mpbs8=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BWOS5crgkMwTGPJDFyBMsqAebonHB8QCi0YFRyZGLPyg8ijT+IjwGmaEUpaqCKVd6lj+aetC1/mxpql7ma9WLzG/lprnZeTTWV0IKe4MLmIYBq4/DB8tCRgMZr/TMSSrcYFH5OB2ZwNVR76Mpa9b5/aV+HpzrvemmX9Nh2IHEpM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=bur.io; spf=pass smtp.mailfrom=bur.io; dkim=pass (2048-bit key) header.d=bur.io header.i=@bur.io header.b=CkUoNkY6; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=mXsiiWlF; arc=none smtp.client-ip=64.147.123.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=bur.io Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bur.io Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bur.io header.i=@bur.io header.b="CkUoNkY6"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="mXsiiWlF" Received: from compute6.internal (compute6.nyi.internal [10.202.2.47]) by mailout.west.internal (Postfix) with ESMTP id A43193200A48; Fri, 2 Feb 2024 18:11:18 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute6.internal (MEProxy); Fri, 02 Feb 2024 18:11:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bur.io; h=cc :content-transfer-encoding:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:subject:subject:to:to; s=fm1; t=1706915478; x= 1707001878; bh=5bdReofwLGtO+8cUIAEc6icgAkBeYI2dmaEEhoxLCeM=; b=C kUoNkY6H3hiKaHxdlbrroU6Y8olhIYN6/9i1c6Cqx7nMIkLeOd3ZMzVWh/P8V2S4 IYKzdUotqTbTSo+9o/OCW2ViBilgdL0S0UZPqtVM4kzP0Rw+Mxl6QflppPlao6qh 0r21EppP9JDdMqzt8WqeAWfa5xH596bFQAOOgxH2AROqQ6ZhAR0DQI7vxQITOyIW xXrv1J7HQuumCNNbIXltNG+4ONY53u0zn6m7AOpPmQ2Gsr40xt8vwFm9ppa8VFe9 sTOp3Hs/CucxY2QcugfEDZ6MOJnP4HlUuYsDAZhx7iWbddnD1zNgUb/C1NUCL4bK yjHVHFwFANDaS2Wkixcag== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:date:feedback-id:feedback-id:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm3; t=1706915478; x=1707001878; bh=5bdReofwLGtO+ 8cUIAEc6icgAkBeYI2dmaEEhoxLCeM=; b=mXsiiWlFYXrFOnRmw9v7VUGSxWCns nW0RyRC2bGMTHvXnDXfU91xYuPVd0W1s87MCPJ751TrR6zyxnViAl548orOso2D1 YeIi5YtzLKNHcpIBMR54v2em7lArsL+b/7oe9KrSkf+l4iUQiV5Xep1N8TX960uY 9nM1xdIunlX1jM+uL/rittYcgzBChZk6DD0C9DwdslpOqXGQXHdincKcnlpDSqm7 oNaR5a2mTqRr9FxABXVXoQum4uANQWy3zElcJF3beI8LZmbq+x74K5VVRMnJt+VN ba37+/9OXMvB8vue2RyQBDIuSvbn+zLnEwmbHGLto6DVFxjGLCJZXCDgg== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvkedrfeduhedgtdejucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefhvffufffkofgjfhgggfestdekre dtredttdenucfhrhhomhepuehorhhishcuuehurhhkohhvuceosghorhhishessghurhdr ihhoqeenucggtffrrghtthgvrhhnpeeiueffuedvieeujefhheeigfekvedujeejjeffve dvhedtudefiefhkeegueehleenucevlhhushhtvghrufhiiigvpedunecurfgrrhgrmhep mhgrihhlfhhrohhmpegsohhrihhssegsuhhrrdhioh X-ME-Proxy: Feedback-ID: i083147f8:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 2 Feb 2024 18:11:17 -0500 (EST) From: Boris Burkov To: linux-btrfs@vger.kernel.org, kernel-team@fb.com Subject: [PATCH 5/6] btrfs: urgent periodic reclaim pass Date: Fri, 2 Feb 2024 15:12:47 -0800 Message-ID: X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Periodic reclaim attempts to avoid block_groups seeing active use with a sweep mark that gets cleared on allocation and set on a sweep. In urgent conditions where we have very little unallocated space, we want to be able to override this mechanism. Introduce a second pass that only happens if we fail to find a reclaim candidate and reclaim is urgent. In that case, do a second pass where all block groups are eligible. Signed-off-by: Boris Burkov --- fs/btrfs/space-info.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index fc4e307669ef..7ec775979637 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -1945,17 +1945,35 @@ int btrfs_calc_reclaim_threshold(struct btrfs_space_info *space_info) return READ_ONCE(space_info->bg_reclaim_threshold); } +/* + * Under "urgent" reclaim, we will reclaim even fresh block groups that have + * recently seen successful allocations, as we are desperate to reclaim + * whatever we can to avoid ENOSPC in a transaction leading to a readonly fs. + */ +static bool is_reclaim_urgent(struct btrfs_space_info *space_info) +{ + struct btrfs_fs_info *fs_info = space_info->fs_info; + u64 unalloc = atomic64_read(&fs_info->free_chunk_space); + u64 chunk_size = min(READ_ONCE(space_info->chunk_size), SZ_1G); + + return unalloc < chunk_size; +} + static int do_reclaim_sweep(struct btrfs_fs_info *fs_info, struct btrfs_space_info *space_info, int raid) { struct btrfs_block_group *bg; int thresh_pct; + bool try_again = true; + bool urgent; spin_lock(&space_info->lock); + urgent = is_reclaim_urgent(space_info); thresh_pct = btrfs_calc_reclaim_threshold(space_info); spin_unlock(&space_info->lock); down_read(&space_info->groups_sem); +again: list_for_each_entry(bg, &space_info->block_groups[raid], list) { u64 thresh; bool reclaim = false; @@ -1963,14 +1981,29 @@ static int do_reclaim_sweep(struct btrfs_fs_info *fs_info, btrfs_get_block_group(bg); spin_lock(&bg->lock); thresh = mult_perc(bg->length, thresh_pct); - if (bg->used < thresh && bg->reclaim_mark) + if (bg->used < thresh && bg->reclaim_mark) { + try_again = false; reclaim = true; + } bg->reclaim_mark++; spin_unlock(&bg->lock); if (reclaim) btrfs_mark_bg_to_reclaim(bg); btrfs_put_block_group(bg); } + + /* + * In situations where we are very motivated to reclaim (low unalloc) + * use two passes to make the reclaim mark check best effort. + * + * If we have any staler groups, we don't touch the fresher ones, but if we + * really need a block group, do take a fresh one. + */ + if (try_again && urgent) { + try_again = false; + goto again; + } + up_read(&space_info->groups_sem); return 0; }