RE: [f2fs-dev] [PATCH 1/2] f2fs: avoid free slab cache under spinlock

From: Chao Yu
Date: Tue Apr 01 2014 - 20:54:03 EST


Hi Kim,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk.kim@xxxxxxxxxxx]
> Sent: Tuesday, April 01, 2014 8:04 PM
> To: Chao Yu
> Cc: linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid free slab cache under spinlock
>
> Hi Chao,
>
> One minor thing as below.
>
> 2014-03-29 (í), 11:29 +0800, Chao Yu:
> > Move kmem_cache_free out of spinlock protection region for better performance.
> >
> > Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
> > ---
> > fs/f2fs/checkpoint.c | 27 +++++++++++++++++----------
> > fs/f2fs/node.c | 15 ++++++++++++++-
> > 2 files changed, 31 insertions(+), 11 deletions(-)
> >
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index a80be51..d877f46 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -347,10 +347,11 @@ void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
> > list_for_each_entry(orphan, head, list) {
> > if (orphan->ino == ino) {
> > list_del(&orphan->list);
> > - kmem_cache_free(orphan_entry_slab, orphan);
> > f2fs_bug_on(sbi->n_orphans == 0);
> > sbi->n_orphans--;
> > - break;
> > + spin_unlock(&sbi->orphan_inode_lock);
> > + kmem_cache_free(orphan_entry_slab, orphan);
> > + return;
> > }
> > }
> > spin_unlock(&sbi->orphan_inode_lock);
> > @@ -577,6 +578,7 @@ void set_dirty_dir_page(struct inode *inode, struct page *page)
> > {
> > struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
> > struct dir_inode_entry *new;
> > + int ret = 0;
> >
> > if (!S_ISDIR(inode->i_mode))
> > return;
> > @@ -586,12 +588,13 @@ void set_dirty_dir_page(struct inode *inode, struct page *page)
> > INIT_LIST_HEAD(&new->list);
> >
> > spin_lock(&sbi->dir_inode_lock);
> > - if (__add_dirty_inode(inode, new))
> > - kmem_cache_free(inode_entry_slab, new);
> > -
> > + ret = __add_dirty_inode(inode, new);
> > inode_inc_dirty_dents(inode);
> > SetPagePrivate(page);
> > spin_unlock(&sbi->dir_inode_lock);
> > +
> > + if (ret)
> > + kmem_cache_free(inode_entry_slab, new);
> > }
> >
> > void add_dirty_dir_inode(struct inode *inode)
> > @@ -599,20 +602,22 @@ void add_dirty_dir_inode(struct inode *inode)
> > struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
> > struct dir_inode_entry *new =
> > f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
> > + int ret = 0;
> >
> > new->inode = inode;
> > INIT_LIST_HEAD(&new->list);
> >
> > spin_lock(&sbi->dir_inode_lock);
> > - if (__add_dirty_inode(inode, new))
> > - kmem_cache_free(inode_entry_slab, new);
> > + ret = __add_dirty_inode(inode, new);
> > spin_unlock(&sbi->dir_inode_lock);
> > +
> > + if (ret)
> > + kmem_cache_free(inode_entry_slab, new);
> > }
> >
> > void remove_dirty_dir_inode(struct inode *inode)
> > {
> > struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
> > -
> > struct list_head *this, *head;
> >
> > if (!S_ISDIR(inode->i_mode))
> > @@ -630,13 +635,15 @@ void remove_dirty_dir_inode(struct inode *inode)
> > entry = list_entry(this, struct dir_inode_entry, list);
> > if (entry->inode == inode) {
> > list_del(&entry->list);
> > - kmem_cache_free(inode_entry_slab, entry);
> > stat_dec_dirty_dir(sbi);
> > - break;
> > + spin_unlock(&sbi->dir_inode_lock);
> > + kmem_cache_free(inode_entry_slab, entry);
> > + goto done;
> > }
> > }
> > spin_unlock(&sbi->dir_inode_lock);
> >
> > +done:
> > /* Only from the recovery routine */
> > if (is_inode_flag_set(F2FS_I(inode), FI_DELAY_IPUT)) {
> > clear_inode_flag(F2FS_I(inode), FI_DELAY_IPUT);
> > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> > index eced8d7..0021056 100644
> > --- a/fs/f2fs/node.c
> > +++ b/fs/f2fs/node.c
> > @@ -1314,7 +1314,6 @@ static void __del_from_free_nid_list(struct f2fs_nm_info *nm_i,
> > {
> > list_del(&i->list);
> > radix_tree_delete(&nm_i->free_nid_root, i->nid);
> > - kmem_cache_free(free_nid_slab, i);
> > }
> >
> > static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build)
> > @@ -1361,13 +1360,19 @@ static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool
> build)
> > static void remove_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
> > {
> > struct free_nid *i;
> > + bool need_free = false;
> > +
> > spin_lock(&nm_i->free_nid_list_lock);
> > i = __lookup_free_nid_list(nm_i, nid);
> > if (i && i->state == NID_NEW) {
> > __del_from_free_nid_list(nm_i, i);
> > nm_i->fcnt--;
> > + need_free = true;
> > }
> > spin_unlock(&nm_i->free_nid_list_lock);
> > +
> > + if (need_free)
> > + kmem_cache_free(free_nid_slab, i);
> > }
> >
> > static void scan_nat_page(struct f2fs_nm_info *nm_i,
> > @@ -1492,6 +1497,8 @@ void alloc_nid_done(struct f2fs_sb_info *sbi, nid_t nid)
> > f2fs_bug_on(!i || i->state != NID_ALLOC);
> > __del_from_free_nid_list(nm_i, i);
> > spin_unlock(&nm_i->free_nid_list_lock);
> > +
> > + kmem_cache_free(free_nid_slab, i);
> > }
> >
> > /*
> > @@ -1501,6 +1508,7 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
> > {
> > struct f2fs_nm_info *nm_i = NM_I(sbi);
> > struct free_nid *i;
> > + bool need_free = false;
> >
> > if (!nid)
> > return;
> > @@ -1510,11 +1518,15 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
> > f2fs_bug_on(!i || i->state != NID_ALLOC);
> > if (!available_free_memory(nm_i, FREE_NIDS)) {
> > __del_from_free_nid_list(nm_i, i);
> > + need_free = true;
> > } else {
> > i->state = NID_NEW;
> > nm_i->fcnt++;
> > }
> > spin_unlock(&nm_i->free_nid_list_lock);
> > +
> > + if (need_free)
> > + kmem_cache_free(free_nid_slab, i);
> > }
> >
> > void recover_node_page(struct f2fs_sb_info *sbi, struct page *page,
> > @@ -1926,6 +1938,7 @@ void destroy_node_manager(struct f2fs_sb_info *sbi)
> > f2fs_bug_on(i->state == NID_ALLOC);
> > __del_from_free_nid_list(nm_i, i);
> > nm_i->fcnt--;
> > + kmem_cache_free(free_nid_slab, i);
>
> It seems that we need to do this too.
>
> spin_unlock(&nm_i->free_nid_list_lock);
> kmem_cache_free(free_nid_slab, i);
> spin_lock(&nm_i->free_nid_list_lock);
>
> Right?

You're right, I will send patch v2.
Thanks for your review.

>
> > }
> > f2fs_bug_on(nm_i->fcnt);
> > spin_unlock(&nm_i->free_nid_list_lock);
>
> --
> Jaegeuk Kim
> Samsung

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