From patchwork Sat Jul 25 12:00:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Coly Li X-Patchwork-Id: 11684993 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5D85A138C for ; Sat, 25 Jul 2020 12:03:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F051206F6 for ; Sat, 25 Jul 2020 12:03:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727040AbgGYMDV (ORCPT ); Sat, 25 Jul 2020 08:03:21 -0400 Received: from mx2.suse.de ([195.135.220.15]:52496 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727023AbgGYMDV (ORCPT ); Sat, 25 Jul 2020 08:03:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 282B9AEAF; Sat, 25 Jul 2020 12:03:28 +0000 (UTC) From: Coly Li To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, Coly Li , Hannes Reinecke Subject: [PATCH 16/25] bcache: introduce meta_bucket_pages() related helper routines Date: Sat, 25 Jul 2020 20:00:30 +0800 Message-Id: <20200725120039.91071-17-colyli@suse.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200725120039.91071-1-colyli@suse.de> References: <20200725120039.91071-1-colyli@suse.de> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Currently the in-memory meta data like c->uuids or c->disk_buckets are allocated by alloc_bucket_pages(). The macro alloc_bucket_pages() calls __get_free_pages() to allocated continuous pages with order indicated by ilog2(bucket_pages(c)), #define alloc_bucket_pages(gfp, c) \ ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c)))) The maximum order is defined as MAX_ORDER, the default value is 11 (and can be overwritten by CONFIG_FORCE_MAX_ZONEORDER). In bcache code the maximum bucket size width is 16bits, this is restricted both by KEY_SIZE size and bucket_size size from struct cache_sb_disk. The maximum 16bits width and power-of-2 value is (1<<15) in unit of sector (512byte). It means the maximum value of bucket size in bytes is (1<<24) bytes a.k.a 4096 pages. When the bucket size is set to maximum permitted value, ilog2(4096) is 12, which exceeds the default maximum order __get_free_pages() can accepted, the failed pages allocation will fail cache set registration procedure and print a kernel oops message for the exceeded pages order. This patch introduces meta_bucket_pages(), meta_bucket_bytes(), and alloc_bucket_pages() helper routines. meta_bucket_pages() indicates the maximum pages can be allocated to meta data bucket, meta_bucket_bytes() indicates the according maximum bytes, and alloc_bucket_pages() does the pages allocation for meta bucket. Because meta_bucket_pages() chooses the smaller value among the bucket size and MAX_ORDER_NR_PAGES, it still works when MAX_ORDER overwritten by CONFIG_FORCE_MAX_ZONEORDER. Following patches will use these helper routines to decide maximum pages can be allocated for different meta data buckets. If the bucket size is larger than meta_bucket_bytes(), the bcache registration can continue to success, just the space more than meta_bucket_bytes() inside the bucket is wasted. Comparing bcache failed for large bucket size, wasting some space for meta data buckets is acceptable at this moment. Signed-off-by: Coly Li Reviewed-by: Hannes Reinecke --- drivers/md/bcache/bcache.h | 20 ++++++++++++++++++++ drivers/md/bcache/super.c | 3 +++ 2 files changed, 23 insertions(+) diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 80e3c4813fb0..972f1aff0f70 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -762,6 +762,26 @@ struct bbio { #define bucket_bytes(c) ((c)->sb.bucket_size << 9) #define block_bytes(c) ((c)->sb.block_size << 9) +static inline unsigned int meta_bucket_pages(struct cache_sb *sb) +{ + unsigned int n, max_pages; + + max_pages = min_t(unsigned int, + __rounddown_pow_of_two(USHRT_MAX) / PAGE_SECTORS, + MAX_ORDER_NR_PAGES); + + n = sb->bucket_size / PAGE_SECTORS; + if (n > max_pages) + n = max_pages; + + return n; +} + +static inline unsigned int meta_bucket_bytes(struct cache_sb *sb) +{ + return meta_bucket_pages(sb) << PAGE_SHIFT; +} + #define prios_per_bucket(c) \ ((bucket_bytes(c) - sizeof(struct prio_set)) / \ sizeof(struct bucket_disk)) diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 214d50903375..d0bdbbc3ff5c 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1821,6 +1821,9 @@ void bch_cache_set_unregister(struct cache_set *c) #define alloc_bucket_pages(gfp, c) \ ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(bucket_pages(c)))) +#define alloc_meta_bucket_pages(gfp, sb) \ + ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb)))) + struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) { int iter_size;