Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755405AbdCJSkx (ORCPT ); Fri, 10 Mar 2017 13:40:53 -0500 Received: from mail.kernel.org ([198.145.29.136]:49842 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755399AbdCJSkp (ORCPT ); Fri, 10 Mar 2017 13:40:45 -0500 Date: Fri, 10 Mar 2017 10:40:41 -0800 From: Jaegeuk Kim To: Kinglong Mee Cc: Chao Yu , chao@kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH] f2fs: skip scanning free nid bitmap of full NAT blocks Message-ID: <20170310184041.GB22979@jaegeuk.local> References: <20170301090907.82629-1-yuchao0@huawei.com> <4ac60332-bc04-f398-3746-4ff5dbe53887@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ac60332-bc04-f398-3746-4ff5dbe53887@gmail.com> User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6164 Lines: 174 On 03/10, Kinglong Mee wrote: > On 3/1/2017 17:09, Chao Yu wrote: > > This patch adds to account free nids for each NAT blocks, and while > > scanning all free nid bitmap, do check count and skip lookuping in > > full NAT block. > > > > Signed-off-by: Chao Yu > > --- > > fs/f2fs/debug.c | 1 + > > fs/f2fs/f2fs.h | 2 ++ > > fs/f2fs/node.c | 34 ++++++++++++++++++++++++++++------ > > 3 files changed, 31 insertions(+), 6 deletions(-) > > > > diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c > > index a77df377e2e8..ee2d0a485fc3 100644 > > --- a/fs/f2fs/debug.c > > +++ b/fs/f2fs/debug.c > > @@ -196,6 +196,7 @@ static void update_mem_info(struct f2fs_sb_info *sbi) > > si->base_mem += (NM_I(sbi)->nat_bits_blocks << F2FS_BLKSIZE_BITS); > > si->base_mem += NM_I(sbi)->nat_blocks * NAT_ENTRY_BITMAP_SIZE; > > si->base_mem += NM_I(sbi)->nat_blocks / 8; > > + si->base_mem += NM_I(sbi)->nat_blocks * sizeof(unsigned short); > > > > get_cache: > > si->cache_mem = 0; > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > > index 7e2924981eeb..c0b33719dfa9 100644 > > --- a/fs/f2fs/f2fs.h > > +++ b/fs/f2fs/f2fs.h > > @@ -557,6 +557,8 @@ struct f2fs_nm_info { > > struct mutex build_lock; /* lock for build free nids */ > > unsigned char (*free_nid_bitmap)[NAT_ENTRY_BITMAP_SIZE]; > > unsigned char *nat_block_bitmap; > > + unsigned short *free_nid_count; /* free nid count of NAT block */ > > + spinlock_t free_nid_lock; /* protect updating of nid count */ > > > > Sorry for my reply so late. > > Is the free_nid_lock needed here? > The free_nid_count should be protected as free_nid_bitmap, > but there isn't any lock for free_nid_bitmap. update_free_nid_bitmap() is covered by nid_list_lock except scan_nat_page. But, it seems build_free_nids() can cover the exception. So, at a glance, we don't need free_nid_lock. Chao, could you check the whole lock coverage again? > How about atomic? IMO, atomic array would not be a proper way. Thanks, > The free node ids management seems a little complex now. > > thanks, > Kinglong Mee > > > /* for checkpoint */ > > char *nat_bitmap; /* NAT bitmap pointer */ > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > > index 94967171dee8..1a759d45b7e4 100644 > > --- a/fs/f2fs/node.c > > +++ b/fs/f2fs/node.c > > @@ -1823,7 +1823,8 @@ static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid) > > kmem_cache_free(free_nid_slab, i); > > } > > > > -void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid, bool set) > > +void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid, > > + bool set, bool build) > > { > > struct f2fs_nm_info *nm_i = NM_I(sbi); > > unsigned int nat_ofs = NAT_BLOCK_OFFSET(nid); > > @@ -1836,6 +1837,13 @@ void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid, bool set) > > set_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]); > > else > > clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]); > > + > > + spin_lock(&nm_i->free_nid_lock); > > + if (set) > > + nm_i->free_nid_count[nat_ofs]++; > > + else if (!build) > > + nm_i->free_nid_count[nat_ofs]--; > > + spin_unlock(&nm_i->free_nid_lock); > > } > > > > static void scan_nat_page(struct f2fs_sb_info *sbi, > > @@ -1847,6 +1855,9 @@ static void scan_nat_page(struct f2fs_sb_info *sbi, > > unsigned int nat_ofs = NAT_BLOCK_OFFSET(start_nid); > > int i; > > > > + if (test_bit_le(nat_ofs, nm_i->nat_block_bitmap)) > > + return; > > + > > set_bit_le(nat_ofs, nm_i->nat_block_bitmap); > > > > i = start_nid % NAT_ENTRY_PER_BLOCK; > > @@ -1861,7 +1872,7 @@ static void scan_nat_page(struct f2fs_sb_info *sbi, > > f2fs_bug_on(sbi, blk_addr == NEW_ADDR); > > if (blk_addr == NULL_ADDR) > > freed = add_free_nid(sbi, start_nid, true); > > - update_free_nid_bitmap(sbi, start_nid, freed); > > + update_free_nid_bitmap(sbi, start_nid, freed, true); > > } > > } > > > > @@ -1877,6 +1888,8 @@ static void scan_free_nid_bits(struct f2fs_sb_info *sbi) > > for (i = 0; i < nm_i->nat_blocks; i++) { > > if (!test_bit_le(i, nm_i->nat_block_bitmap)) > > continue; > > + if (!nm_i->free_nid_count[i]) > > + continue; > > for (idx = 0; idx < NAT_ENTRY_PER_BLOCK; idx++) { > > nid_t nid; > > > > @@ -2081,7 +2094,7 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid) > > __insert_nid_to_list(sbi, i, ALLOC_NID_LIST, false); > > nm_i->available_nids--; > > > > - update_free_nid_bitmap(sbi, *nid, false); > > + update_free_nid_bitmap(sbi, *nid, false, false); > > > > spin_unlock(&nm_i->nid_list_lock); > > return true; > > @@ -2137,7 +2150,7 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid) > > > > nm_i->available_nids++; > > > > - update_free_nid_bitmap(sbi, nid, true); > > + update_free_nid_bitmap(sbi, nid, true, false); > > > > spin_unlock(&nm_i->nid_list_lock); > > > > @@ -2467,11 +2480,11 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi, > > add_free_nid(sbi, nid, false); > > spin_lock(&NM_I(sbi)->nid_list_lock); > > NM_I(sbi)->available_nids++; > > - update_free_nid_bitmap(sbi, nid, true); > > + update_free_nid_bitmap(sbi, nid, true, false); > > spin_unlock(&NM_I(sbi)->nid_list_lock); > > } else { > > spin_lock(&NM_I(sbi)->nid_list_lock); > > - update_free_nid_bitmap(sbi, nid, false); > > + update_free_nid_bitmap(sbi, nid, false, false); > > spin_unlock(&NM_I(sbi)->nid_list_lock); > > } > > } > > @@ -2651,6 +2664,14 @@ int init_free_nid_cache(struct f2fs_sb_info *sbi) > > GFP_KERNEL); > > if (!nm_i->nat_block_bitmap) > > return -ENOMEM; > > + > > + nm_i->free_nid_count = f2fs_kvzalloc(nm_i->nat_blocks * > > + sizeof(unsigned short), GFP_KERNEL); > > + if (!nm_i->free_nid_count) > > + return -ENOMEM; > > + > > + spin_lock_init(&nm_i->free_nid_lock); > > + > > return 0; > > } > > > > @@ -2730,6 +2751,7 @@ void destroy_node_manager(struct f2fs_sb_info *sbi) > > > > kvfree(nm_i->nat_block_bitmap); > > kvfree(nm_i->free_nid_bitmap); > > + kvfree(nm_i->free_nid_count); > > > > kfree(nm_i->nat_bitmap); > > kfree(nm_i->nat_bits); > >