From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6133C432C0 for ; Mon, 25 Nov 2019 19:47:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C0B1F2075C for ; Mon, 25 Nov 2019 19:47:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574711253; bh=sIzf3UTUducXI/7JkZWC/786gPgYfXSjvFIi1XC6SE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=I5jikQDjJ4vSucc5l/H9hJoFaOllBSxMPB2V7lUYFFzeeibz5gY5yv9WApjd/KKq6 TDZIUsefd/3vAvv91mTa2kQ9b4L0306grtufs1TF0Z0HWdsn88YyjN3iF2xpztG+nm AJEtHMGaF+qkiN9pmNgc5blGwsG+Q9DsWX2saq2E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727198AbfKYTrc (ORCPT ); Mon, 25 Nov 2019 14:47:32 -0500 Received: from mail-qv1-f65.google.com ([209.85.219.65]:46109 "EHLO mail-qv1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727187AbfKYTrb (ORCPT ); Mon, 25 Nov 2019 14:47:31 -0500 Received: by mail-qv1-f65.google.com with SMTP id w11so6253229qvu.13 for ; Mon, 25 Nov 2019 11:47:31 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:in-reply-to:references; bh=/55shlXn5U81maiE2JbP9Y20nOk8gQoXsZiv9oaLK/M=; b=SVwFlHB8vKFBu3FetWD3yOgU1IwQKnAKr5+t439B7hV5X4PVvwfWSAonNb/D5BkqK6 G2GgDiMcRNp4Il78PItU4dwc+NJQBqNAb26cSIKGVu0FwB3JGSIfI5DvJ5pY146VescF u9Nd8mGAmcmXwoJUJkXEJKP3V7STie+MYJizdyH1G1Zwx9MPRJaKC00S2bsgyEDvtUse 8zwKqMTmuOo95pAfBEkeT0l6iyR3iXE67Vaw7oSz4iA8wmRgz21dMDGMRl/AmmeW2SuC YEWdAlkwOrsAPk1lkHP7YhkUsfiaiwyZ/Yojnk6oF2X1EtAXXRvwo/mnRsF2to6//xjh Soow== X-Gm-Message-State: APjAAAWoDQSJewAuWa85YoYR9yvCa0Ws1xkaI3O6Xz6KRH6jQMoPX92k 2SkD/dh2B+wVwsv6xrJZ2mw= X-Google-Smtp-Source: APXvYqyMfWFn6uhxCuDQYS07cgLAKOYyCc74u2UDZak2XYN4dMPzI9ghW02vy+mfk/MPz6BF73pLgg== X-Received: by 2002:ad4:462d:: with SMTP id x13mr29356075qvv.105.1574711250651; Mon, 25 Nov 2019 11:47:30 -0800 (PST) Received: from dennisz-mbp.thefacebook.com ([163.114.130.128]) by smtp.gmail.com with ESMTPSA id o13sm4481033qto.96.2019.11.25.11.47.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 25 Nov 2019 11:47:29 -0800 (PST) From: Dennis Zhou To: David Sterba , Chris Mason , Josef Bacik , Omar Sandoval Cc: kernel-team@fb.com, linux-btrfs@vger.kernel.org, Dennis Zhou Subject: [PATCH 21/22] btrfs: increase the metadata allowance for the free_space_cache Date: Mon, 25 Nov 2019 14:47:01 -0500 Message-Id: <894355ca977324aec8587d16625ed5ce10b23e55.1574709825.git.dennis@kernel.org> X-Mailer: git-send-email 2.13.5 In-Reply-To: References: In-Reply-To: References: Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Currently, there is no way for the free space cache to recover from being serviced by purely bitmaps because the extent threshold is set to 0 in recalculate_thresholds() when we surpass the metadata allowance. This adds a recovery mechanism by keeping large extents out of the bitmaps and increases the metadata upper bound to 64KB. The recovery mechanism bypasses this upper bound, thus making it a soft upper bound. But, with the bypass being 1MB or greater, it shouldn't add unbounded overhead. Signed-off-by: Dennis Zhou Reviewed-by: Josef Bacik --- fs/btrfs/free-space-cache.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-) diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 1b887c0d7508..15667095c50d 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -24,7 +24,8 @@ #include "discard.h" #define BITS_PER_BITMAP (PAGE_SIZE * 8UL) -#define MAX_CACHE_BYTES_PER_GIG SZ_32K +#define MAX_CACHE_BYTES_PER_GIG SZ_64K +#define FORCE_EXTENT_THRESHOLD SZ_1M struct btrfs_trim_range { u64 start; @@ -1695,26 +1696,17 @@ static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) ASSERT(ctl->total_bitmaps <= max_bitmaps); /* - * The goal is to keep the total amount of memory used per 1gb of space - * at or below 32k, so we need to adjust how much memory we allow to be - * used by extent based free space tracking + * We are trying to keep the total amount of memory used per 1gb of + * space to be MAX_CACHE_BYTES_PER_GIG. However, with a reclamation + * mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of + * bitmaps, we may end up using more memory than this. */ if (size < SZ_1G) max_bytes = MAX_CACHE_BYTES_PER_GIG; else max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G); - /* - * we want to account for 1 more bitmap than what we have so we can make - * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as - * we add more bitmaps. - */ - bitmap_bytes = (ctl->total_bitmaps + 1) * ctl->unit; - - if (bitmap_bytes >= max_bytes) { - ctl->extents_thresh = 0; - return; - } + bitmap_bytes = ctl->total_bitmaps * ctl->unit; /* * we want the extent entry threshold to always be at most 1/2 the max @@ -2100,6 +2092,10 @@ static bool use_bitmap(struct btrfs_free_space_ctl *ctl, forced = true; #endif + /* This is a way to reclaim large regions from the bitmaps. */ + if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD) + return false; + /* * If we are below the extents threshold then we can add this as an * extent, and don't have to deal with the bitmap -- 2.17.1