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=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 AACBCC433E2 for ; Thu, 16 Jul 2020 06:15:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 926E420720 for ; Thu, 16 Jul 2020 06:15:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727768AbgGPGPI (ORCPT ); Thu, 16 Jul 2020 02:15:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:45164 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726547AbgGPGPI (ORCPT ); Thu, 16 Jul 2020 02:15:08 -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 AA56DAD6A; Thu, 16 Jul 2020 06:15:08 +0000 (UTC) Subject: Re: [PATCH v3 13/16] bcache: add bucket_size_hi into struct cache_sb_disk for large bucket To: colyli@suse.de, linux-bcache@vger.kernel.org Cc: linux-block@vger.kernel.org References: <20200715143015.14957-1-colyli@suse.de> <20200715143015.14957-14-colyli@suse.de> From: Hannes Reinecke Message-ID: Date: Thu, 16 Jul 2020 08:15:02 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200715143015.14957-14-colyli@suse.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-bcache-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org On 7/15/20 4:30 PM, colyli@suse.de wrote: > From: Coly Li > > The large bucket feature is to extend bucket_size from 16bit to 32bit. > > When create cache device on zoned device (e.g. zoned NVMe SSD), making > a single bucket cover one or more zones of the zoned device is the > simplest way to support zoned device as cache by bcache. > > But current maximum bucket size is 16MB and a typical zone size of zoned > device is 256MB, this is the major motiviation to extend bucket size to > a larger bit width. > > This patch is the basic and first change to support large bucket size, > the major changes it makes are, > - Add BCH_FEATURE_INCOMPAT_LARGE_BUCKET for the large bucket feature, > INCOMPAT means it introduces incompatible on-disk format change. > - Add BCH_FEATURE_INCOMPAT_FUNCS(large_bucket, LARGE_BUCKET) routines. > - Adds __le32 bucket_size_hi into struct cache_sb_disk at offset 0x8d0 > for the on-disk super block format. > - For the in-memory super block struct cache_sb, member bucket_size is > extended from __u16 to __32. > - Add get_bucket_size() to combine the bucket_size and bucket_size_hi > from struct cache_sb_disk into an unsigned int value. > > Since we already have large bucket size helpers meta_bucket_pages(), > meta_bucket_bytes() and alloc_meta_bucket_pages(), they make sure when > bucket size > 8MB, the memory allocation for bcache meta data bucket > won't fail no matter how large the bucket size extended. So these meta > data buckets are handled properly when the bucket size width increase > from 16bit to 32bit, we don't need to worry about them. > > Signed-off-by: Coly Li > --- > drivers/md/bcache/alloc.c | 2 +- > drivers/md/bcache/features.c | 22 ++++++++++++++++++++++ > drivers/md/bcache/features.h | 9 ++++++--- > drivers/md/bcache/movinggc.c | 4 ++-- > drivers/md/bcache/super.c | 23 +++++++++++++++++++---- > include/uapi/linux/bcache.h | 3 ++- > 6 files changed, 52 insertions(+), 11 deletions(-) > create mode 100644 drivers/md/bcache/features.c > > diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c > index a1df0d95151c..52035a78d836 100644 > --- a/drivers/md/bcache/alloc.c > +++ b/drivers/md/bcache/alloc.c > @@ -87,7 +87,7 @@ void bch_rescale_priorities(struct cache_set *c, int sectors) > { > struct cache *ca; > struct bucket *b; > - unsigned int next = c->nbuckets * c->sb.bucket_size / 1024; > + unsigned long next = c->nbuckets * c->sb.bucket_size / 1024; > unsigned int i; > int r; > > diff --git a/drivers/md/bcache/features.c b/drivers/md/bcache/features.c > new file mode 100644 > index 000000000000..ba53944bb390 > --- /dev/null > +++ b/drivers/md/bcache/features.c > @@ -0,0 +1,22 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Feature set bits and string conversion. > + * Inspired by ext4's features compat/incompat/ro_compat related code. > + * > + * Copyright 2020 Coly Li > + * > + */ > +#include > +#include "bcache.h" > + > +struct feature { > + int compat; > + unsigned int mask; > + const char *string; > +}; > + > +static struct feature feature_list[] = { > + {BCH_FEATURE_INCOMPAT, BCH_FEATURE_INCOMPAT_LARGE_BUCKET, > + "large_bucket"}, > + {0, 0, 0 }, > +}; > diff --git a/drivers/md/bcache/features.h b/drivers/md/bcache/features.h > index ae7df37b9862..dca052cf5203 100644 > --- a/drivers/md/bcache/features.h > +++ b/drivers/md/bcache/features.h > @@ -11,9 +11,13 @@ > #define BCH_FEATURE_INCOMPAT 2 > #define BCH_FEATURE_TYPE_MASK 0x03 > > +/* Feature set definition */ > +/* Incompat feature set */ > +#define BCH_FEATURE_INCOMPAT_LARGE_BUCKET 0x0001 /* 32bit bucket size */ > + > #define BCH_FEATURE_COMPAT_SUUP 0 > #define BCH_FEATURE_RO_COMPAT_SUUP 0 > -#define BCH_FEATURE_INCOMPAT_SUUP 0 > +#define BCH_FEATURE_INCOMPAT_SUUP BCH_FEATURE_INCOMPAT_LARGE_BUCKET > > #define BCH_HAS_COMPAT_FEATURE(sb, mask) \ > ((sb)->feature_compat & (mask)) > @@ -22,8 +26,6 @@ > #define BCH_HAS_INCOMPAT_FEATURE(sb, mask) \ > ((sb)->feature_incompat & (mask)) > > -/* Feature set definition */ > - > #define BCH_FEATURE_COMPAT_FUNCS(name, flagname) \ > static inline int bch_has_feature_##name(struct cache_sb *sb) \ > { \ > @@ -75,4 +77,5 @@ static inline void bch_clear_feature_##name(struct cache_sb *sb) \ > ~BCH##_FEATURE_INCOMPAT_##flagname; \ > } > > +BCH_FEATURE_INCOMPAT_FUNCS(large_bucket, LARGE_BUCKET); > #endif > diff --git a/drivers/md/bcache/movinggc.c b/drivers/md/bcache/movinggc.c > index b7dd2d75f58c..5872d6470470 100644 > --- a/drivers/md/bcache/movinggc.c > +++ b/drivers/md/bcache/movinggc.c > @@ -206,8 +206,8 @@ void bch_moving_gc(struct cache_set *c) > mutex_lock(&c->bucket_lock); > > for_each_cache(ca, c, i) { > - unsigned int sectors_to_move = 0; > - unsigned int reserve_sectors = ca->sb.bucket_size * > + unsigned long sectors_to_move = 0; > + unsigned long reserve_sectors = ca->sb.bucket_size * > fifo_used(&ca->free[RESERVE_MOVINGGC]); > > ca->heap.used = 0; > diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c > index 02901d0ae8e2..e0da52f8e8c9 100644 > --- a/drivers/md/bcache/super.c > +++ b/drivers/md/bcache/super.c > @@ -60,6 +60,17 @@ struct workqueue_struct *bch_journal_wq; > > /* Superblock */ > > +static unsigned int get_bucket_size(struct cache_sb *sb, struct cache_sb_disk *s) > +{ > + unsigned int bucket_size = le16_to_cpu(s->bucket_size); > + > + if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES && > + bch_has_feature_large_bucket(sb)) > + bucket_size |= le32_to_cpu(s->bucket_size_hi) << 16; > + > + return bucket_size; > +} > + > static const char *read_super_common(struct cache_sb *sb, struct block_device *bdev, > struct cache_sb_disk *s) > { That is a bit unfortunate; bucket_size_hi is 32 bits, so we might end up with an overflow here if bucket_size_hi is larger that USHRT_MAX. So to avoid overflow either make bucket_size_hi 16 bit, too, or define this feature such that the original bucket_size field is ignored and just the new size field is used. Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer