| Message ID | 20200422212102.3757660-11-ira.weiny@intel.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | XFS - Enable per-file/per-directory DAX operations V10 | expand |
On Wed 22-04-20 14:21:01, ira.weiny@intel.com wrote: > From: Ira Weiny <ira.weiny@intel.com> > > DCACHE_DONTCACHE indicates a dentry should not be cached on final > dput(). > > Also add a helper function to mark DCACHE_DONTCACHE on all dentries > pointing to a specific inode when that inode is being set I_DONTCACHE. > > This facilitates dropping dentry references to inodes sooner which > require eviction to swap S_DAX mode. > > Cc: Al Viro <viro@zeniv.linux.org.uk> > Signed-off-by: Ira Weiny <ira.weiny@intel.com> The patch looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > > --- > Changes from V9: > modify i_state under i_lock > Update comment > "Purge from memory on final dput()" > > Changes from V8: > Update commit message > Use mark_inode_dontcache in XFS > Fix locking... can't use rcu here. > Change name to mark_inode_dontcache > --- > fs/dcache.c | 4 ++++ > fs/inode.c | 15 +++++++++++++++ > fs/xfs/xfs_icache.c | 2 +- > include/linux/dcache.h | 2 ++ > include/linux/fs.h | 1 + > 5 files changed, 23 insertions(+), 1 deletion(-) > > diff --git a/fs/dcache.c b/fs/dcache.c > index b280e07e162b..0030fabab2c4 100644 > --- a/fs/dcache.c > +++ b/fs/dcache.c > @@ -647,6 +647,10 @@ static inline bool retain_dentry(struct dentry *dentry) > if (dentry->d_op->d_delete(dentry)) > return false; > } > + > + if (unlikely(dentry->d_flags & DCACHE_DONTCACHE)) > + return false; > + > /* retain; LRU fodder */ > dentry->d_lockref.count--; > if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST))) > diff --git a/fs/inode.c b/fs/inode.c > index 93d9252a00ab..316355433797 100644 > --- a/fs/inode.c > +++ b/fs/inode.c > @@ -1526,6 +1526,21 @@ int generic_delete_inode(struct inode *inode) > } > EXPORT_SYMBOL(generic_delete_inode); > > +void mark_inode_dontcache(struct inode *inode) > +{ > + struct dentry *de; > + > + spin_lock(&inode->i_lock); > + hlist_for_each_entry(de, &inode->i_dentry, d_u.d_alias) { > + spin_lock(&de->d_lock); > + de->d_flags |= DCACHE_DONTCACHE; > + spin_unlock(&de->d_lock); > + } > + inode->i_state |= I_DONTCACHE; > + spin_unlock(&inode->i_lock); > +} > +EXPORT_SYMBOL(mark_inode_dontcache); > + > /* > * Called when we're dropping the last reference > * to an inode. > diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c > index de76f7f60695..3c8f44477804 100644 > --- a/fs/xfs/xfs_icache.c > +++ b/fs/xfs/xfs_icache.c > @@ -559,7 +559,7 @@ xfs_iget_cache_miss( > */ > iflags = XFS_INEW; > if (flags & XFS_IGET_DONTCACHE) > - VFS_I(ip)->i_state |= I_DONTCACHE; > + mark_inode_dontcache(VFS_I(ip)); > ip->i_udquot = NULL; > ip->i_gdquot = NULL; > ip->i_pdquot = NULL; > diff --git a/include/linux/dcache.h b/include/linux/dcache.h > index c1488cc84fd9..a81f0c3cf352 100644 > --- a/include/linux/dcache.h > +++ b/include/linux/dcache.h > @@ -177,6 +177,8 @@ struct dentry_operations { > > #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ > > +#define DCACHE_DONTCACHE 0x00000080 /* Purge from memory on final dput() */ > + > #define DCACHE_CANT_MOUNT 0x00000100 > #define DCACHE_GENOCIDE 0x00000200 > #define DCACHE_SHRINK_LIST 0x00000400 > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 44bd45af760f..064168ec2e0b 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -3055,6 +3055,7 @@ static inline int generic_drop_inode(struct inode *inode) > return !inode->i_nlink || inode_unhashed(inode) || > (inode->i_state & I_DONTCACHE); > } > +extern void mark_inode_dontcache(struct inode *inode); > > extern struct inode *ilookup5_nowait(struct super_block *sb, > unsigned long hashval, int (*test)(struct inode *, void *), > -- > 2.25.1 >
On Wed, Apr 22, 2020 at 02:21:01PM -0700, ira.weiny@intel.com wrote: > From: Ira Weiny <ira.weiny@intel.com> > > DCACHE_DONTCACHE indicates a dentry should not be cached on final > dput(). > > Also add a helper function to mark DCACHE_DONTCACHE on all dentries > pointing to a specific inode when that inode is being set I_DONTCACHE. > > This facilitates dropping dentry references to inodes sooner which > require eviction to swap S_DAX mode. > > Cc: Al Viro <viro@zeniv.linux.org.uk> > Signed-off-by: Ira Weiny <ira.weiny@intel.com> Code looks fine.... > --- a/fs/inode.c > +++ b/fs/inode.c > @@ -1526,6 +1526,21 @@ int generic_delete_inode(struct inode *inode) > } > EXPORT_SYMBOL(generic_delete_inode); > > +void mark_inode_dontcache(struct inode *inode) > +{ > + struct dentry *de; > + > + spin_lock(&inode->i_lock); > + hlist_for_each_entry(de, &inode->i_dentry, d_u.d_alias) { > + spin_lock(&de->d_lock); > + de->d_flags |= DCACHE_DONTCACHE; > + spin_unlock(&de->d_lock); > + } > + inode->i_state |= I_DONTCACHE; > + spin_unlock(&inode->i_lock); > +} > +EXPORT_SYMBOL(mark_inode_dontcache); Though I suspect that this should be in fs/dcache.c and not fs/inode.c. i.e. nothing in fs/inode.c does dentry list walks, but there are several cases in the dcache code where inode dentry walks are done under the inode lock (e.g. d_find_alias(inode)). So perhaps this should be d_mark_dontcache(inode), which also marks the inode as I_DONTCACHE so that everything is evicted on last reference... Cheers, Dave.
On Fri, Apr 24, 2020 at 08:57:34AM +1000, Dave Chinner wrote: > On Wed, Apr 22, 2020 at 02:21:01PM -0700, ira.weiny@intel.com wrote: > > From: Ira Weiny <ira.weiny@intel.com> > > > > DCACHE_DONTCACHE indicates a dentry should not be cached on final > > dput(). > > > > Also add a helper function to mark DCACHE_DONTCACHE on all dentries > > pointing to a specific inode when that inode is being set I_DONTCACHE. > > > > This facilitates dropping dentry references to inodes sooner which > > require eviction to swap S_DAX mode. > > > > Cc: Al Viro <viro@zeniv.linux.org.uk> > > Signed-off-by: Ira Weiny <ira.weiny@intel.com> > > Code looks fine.... > > > --- a/fs/inode.c > > +++ b/fs/inode.c > > @@ -1526,6 +1526,21 @@ int generic_delete_inode(struct inode *inode) > > } > > EXPORT_SYMBOL(generic_delete_inode); > > > > +void mark_inode_dontcache(struct inode *inode) > > +{ > > + struct dentry *de; > > + > > + spin_lock(&inode->i_lock); > > + hlist_for_each_entry(de, &inode->i_dentry, d_u.d_alias) { > > + spin_lock(&de->d_lock); > > + de->d_flags |= DCACHE_DONTCACHE; > > + spin_unlock(&de->d_lock); > > + } > > + inode->i_state |= I_DONTCACHE; > > + spin_unlock(&inode->i_lock); > > +} > > +EXPORT_SYMBOL(mark_inode_dontcache); > > Though I suspect that this should be in fs/dcache.c and not > fs/inode.c. i.e. nothing in fs/inode.c does dentry list walks, but > there are several cases in the dcache code where inode dentry walks > are done under the inode lock (e.g. d_find_alias(inode)). > > So perhaps this should be d_mark_dontcache(inode), which also marks > the inode as I_DONTCACHE so that everything is evicted on last > reference... That does follow an existing pattern. Al? Any preference? Ira > > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com
diff --git a/fs/dcache.c b/fs/dcache.c index b280e07e162b..0030fabab2c4 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -647,6 +647,10 @@ static inline bool retain_dentry(struct dentry *dentry) if (dentry->d_op->d_delete(dentry)) return false; } + + if (unlikely(dentry->d_flags & DCACHE_DONTCACHE)) + return false; + /* retain; LRU fodder */ dentry->d_lockref.count--; if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST))) diff --git a/fs/inode.c b/fs/inode.c index 93d9252a00ab..316355433797 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1526,6 +1526,21 @@ int generic_delete_inode(struct inode *inode) } EXPORT_SYMBOL(generic_delete_inode); +void mark_inode_dontcache(struct inode *inode) +{ + struct dentry *de; + + spin_lock(&inode->i_lock); + hlist_for_each_entry(de, &inode->i_dentry, d_u.d_alias) { + spin_lock(&de->d_lock); + de->d_flags |= DCACHE_DONTCACHE; + spin_unlock(&de->d_lock); + } + inode->i_state |= I_DONTCACHE; + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL(mark_inode_dontcache); + /* * Called when we're dropping the last reference * to an inode. diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c index de76f7f60695..3c8f44477804 100644 --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -559,7 +559,7 @@ xfs_iget_cache_miss( */ iflags = XFS_INEW; if (flags & XFS_IGET_DONTCACHE) - VFS_I(ip)->i_state |= I_DONTCACHE; + mark_inode_dontcache(VFS_I(ip)); ip->i_udquot = NULL; ip->i_gdquot = NULL; ip->i_pdquot = NULL; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index c1488cc84fd9..a81f0c3cf352 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -177,6 +177,8 @@ struct dentry_operations { #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ +#define DCACHE_DONTCACHE 0x00000080 /* Purge from memory on final dput() */ + #define DCACHE_CANT_MOUNT 0x00000100 #define DCACHE_GENOCIDE 0x00000200 #define DCACHE_SHRINK_LIST 0x00000400 diff --git a/include/linux/fs.h b/include/linux/fs.h index 44bd45af760f..064168ec2e0b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3055,6 +3055,7 @@ static inline int generic_drop_inode(struct inode *inode) return !inode->i_nlink || inode_unhashed(inode) || (inode->i_state & I_DONTCACHE); } +extern void mark_inode_dontcache(struct inode *inode); extern struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, int (*test)(struct inode *, void *),