From: Chao Yu Subject: RE: [PATCH 1/2] f2fs: flush dirty nat entries when exceeding threshold Date: Mon, 18 Jan 2016 11:13:08 +0800 Message-ID: <019c01d1519e$3fe1a490$bfa4edb0$@samsung.com> References: <017d01d15041$7fad3890$7f07a9b0$@samsung.com> <20160116202958.GA67230@jaegeuk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20160116202958.GA67230@jaegeuk> Content-language: zh-cn Sender: linux-kernel-owner@vger.kernel.org To: 'Jaegeuk Kim' Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org List-Id: linux-f2fs-devel.lists.sourceforge.net Hi Jaegeuk, > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org] > Sent: Sunday, January 17, 2016 4:30 AM > To: Chao Yu > Cc: linux-f2fs-devel@lists.sourceforge.net; linux-kernel@vger.kernel.org > Subject: Re: [PATCH 1/2] f2fs: flush dirty nat entries when exceeding threshold > > Hi Chao, > > On Sat, Jan 16, 2016 at 05:36:40PM +0800, Chao Yu wrote: > > When testing f2fs with xfstest, generic/251 is stuck for long time, > > the case uses below serials to obtain fresh released space in device, > > in order to preparing for following fstrim test. > > > > 1. rm -rf /mnt/dir > > 2. mkdir /mnt/dir/ > > 3. cp -axT `pwd`/ /mnt/dir/ > > 4. goto 1 > > > > During preparing step, all nat entries will be cached in nat cache, > > most of them are dirty entries with invalid blkaddr, which means > > nodes related to these entries have been truncated, and they could > > be reused after the dirty entries been checkpointed. > > > > However, there was no checkpoint been triggered, so nid allocators > > (e.g. mkdir, creat) will run into long journey of iterating all NAT > > pages, looking for free nids in alloc_nid->build_free_nids. > > > > Here, we give another chance to f2fs_balance_fs_bg to do checkpoint > > to flush nat entries for reusing in free nid cache when dirty entry > > count exceeds 10% of max count. > > > > Signed-off-by: Chao Yu > > --- > > fs/f2fs/node.h | 8 ++++++++ > > fs/f2fs/segment.c | 3 ++- > > 2 files changed, 10 insertions(+), 1 deletion(-) > > > > diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h > > index d4d1f63..630c62d 100644 > > --- a/fs/f2fs/node.h > > +++ b/fs/f2fs/node.h > > @@ -25,6 +25,8 @@ > > /* control the memory footprint threshold (10MB per 1GB ram) */ > > #define DEF_RAM_THRESHOLD 10 > > > > +#define DEF_DIRTY_NAT_THRESHOLD 10 /* 10% over max nid */ > > + > > /* vector size for gang look-up from nat cache that consists of radix tree */ > > #define NATVEC_SIZE 64 > > #define SETVEC_SIZE 32 > > @@ -117,6 +119,12 @@ static inline void raw_nat_from_node_info(struct f2fs_nat_entry *raw_ne, > > raw_ne->version = ni->version; > > } > > > > +static inline bool excess_dirty_nats(struct f2fs_sb_info *sbi) > > +{ > > + return NM_I(sbi)->dirty_nat_cnt >= > > + NM_I(sbi)->max_nid * DEF_DIRTY_NAT_THRESHOLD / 100; > > Need to add a sysfs entry? Agreed, let me export the sysfs entry in another patch, distinguishing with current bug fixing patch. Thanks, > > Thanks, > > > +} > > + > > enum mem_type { > > FREE_NIDS, /* indicates the free nid list */ > > NAT_ENTRIES, /* indicates the cached nat entry */ > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > > index 5904a41..68800e6 100644 > > --- a/fs/f2fs/segment.c > > +++ b/fs/f2fs/segment.c > > @@ -291,8 +291,9 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi) > > > > /* checkpoint is the only way to shrink partial cached entries */ > > if (!available_free_memory(sbi, NAT_ENTRIES) || > > - excess_prefree_segs(sbi) || > > !available_free_memory(sbi, INO_ENTRIES) || > > + excess_prefree_segs(sbi) || > > + excess_dirty_nats(sbi) || > > (is_idle(sbi) && f2fs_time_over(sbi, CP_TIME))) { > > if (test_opt(sbi, DATA_FLUSH)) > > sync_dirty_inodes(sbi, FILE_INODE); > > -- > > 2.6.3 > >