| Message ID | 20240319071952.682266-1-hch@lst.de (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | xfs: compile out v4 support if disabled | expand |
On Tue, Mar 19, 2024 at 05:19:51PM +1000, Christoph Hellwig wrote: > Add a strategic IS_ENABLED to let the compiler eliminate the unused > non-crc code is CONFIG_XFS_SUPPORT_V4 is disabled. > > This saves almost 20k worth of .text for my .config: > > $ size xfs.o.* > text data bss dec hex filename > 1351126 294836 592 1646554 191fda xfs.o.new > 1371453 294868 592 1666913 196f61 xfs.o.old > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/xfs/xfs_mount.h | 7 ++++++- > fs/xfs/xfs_super.c | 22 +++++++++++++--------- > 2 files changed, 19 insertions(+), 10 deletions(-) > > diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h > index e880aa48de68bb..24fe6e7913c49f 100644 > --- a/fs/xfs/xfs_mount.h > +++ b/fs/xfs/xfs_mount.h > @@ -327,6 +327,12 @@ static inline void xfs_add_ ## name (struct xfs_mount *mp) \ > xfs_sb_version_add ## name(&mp->m_sb); \ > } > > +static inline bool xfs_has_crc(struct xfs_mount *mp) > +{ > + return IS_ENABLED(CONFIG_XFS_SUPPORT_V4) && > + (mp->m_features & XFS_FEAT_CRC); Can you save even more text bytes by defining xfs_has_{nlink,v3inodes,projid32,lazysbcount,pquotino,attr2} to 1? And I guess defining noattr2 to 0? --D > +} > + > /* Superblock features */ > __XFS_ADD_FEAT(attr, ATTR) > __XFS_HAS_FEAT(nlink, NLINK) > @@ -341,7 +347,6 @@ __XFS_HAS_FEAT(lazysbcount, LAZYSBCOUNT) > __XFS_ADD_FEAT(attr2, ATTR2) > __XFS_HAS_FEAT(parent, PARENT) > __XFS_ADD_FEAT(projid32, PROJID32) > -__XFS_HAS_FEAT(crc, CRC) > __XFS_HAS_FEAT(v3inodes, V3INODES) > __XFS_HAS_FEAT(pquotino, PQUOTINO) > __XFS_HAS_FEAT(ftype, FTYPE) > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > index 6828c48b15e9bd..7d972e1179255b 100644 > --- a/fs/xfs/xfs_super.c > +++ b/fs/xfs/xfs_super.c > @@ -1580,17 +1580,21 @@ xfs_fs_fill_super( > if (error) > goto out_free_sb; > > - /* V4 support is undergoing deprecation. */ > - if (!xfs_has_crc(mp)) { > -#ifdef CONFIG_XFS_SUPPORT_V4 > + /* > + * V4 support is undergoing deprecation. > + * > + * Note: this has to use an open coded m_features check as xfs_has_crc > + * always returns false for !CONFIG_XFS_SUPPORT_V4. > + */ > + if (!(mp->m_features & XFS_FEAT_CRC)) { > + if (!IS_ENABLED(CONFIG_XFS_SUPPORT_V4)) { > + xfs_warn(mp, > + "Deprecated V4 format (crc=0) not supported by kernel."); > + error = -EINVAL; > + goto out_free_sb; > + } > xfs_warn_once(mp, > "Deprecated V4 format (crc=0) will not be supported after September 2030."); > -#else > - xfs_warn(mp, > - "Deprecated V4 format (crc=0) not supported by kernel."); > - error = -EINVAL; > - goto out_free_sb; > -#endif > } > > /* ASCII case insensitivity is undergoing deprecation. */ > -- > 2.39.2 > >
On Tue, Mar 19, 2024 at 10:59:09AM -0700, Darrick J. Wong wrote: > > +static inline bool xfs_has_crc(struct xfs_mount *mp) > > +{ > > + return IS_ENABLED(CONFIG_XFS_SUPPORT_V4) && > > + (mp->m_features & XFS_FEAT_CRC); > > Can you save even more text bytes by defining > xfs_has_{nlink,v3inodes,projid32,lazysbcount,pquotino,attr2} to 1? > And I guess defining noattr2 to 0? I guess I can give it a try.
On Tue, Mar 19, 2024 at 05:19:51PM +1000, Christoph Hellwig wrote: > Add a strategic IS_ENABLED to let the compiler eliminate the unused > non-crc code is CONFIG_XFS_SUPPORT_V4 is disabled. > > This saves almost 20k worth of .text for my .config: > > $ size xfs.o.* > text data bss dec hex filename > 1351126 294836 592 1646554 191fda xfs.o.new > 1371453 294868 592 1666913 196f61 xfs.o.old > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/xfs/xfs_mount.h | 7 ++++++- > fs/xfs/xfs_super.c | 22 +++++++++++++--------- > 2 files changed, 19 insertions(+), 10 deletions(-) > > diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h > index e880aa48de68bb..24fe6e7913c49f 100644 > --- a/fs/xfs/xfs_mount.h > +++ b/fs/xfs/xfs_mount.h > @@ -327,6 +327,12 @@ static inline void xfs_add_ ## name (struct xfs_mount *mp) \ > xfs_sb_version_add ## name(&mp->m_sb); \ > } > > +static inline bool xfs_has_crc(struct xfs_mount *mp) > +{ > + return IS_ENABLED(CONFIG_XFS_SUPPORT_V4) && > + (mp->m_features & XFS_FEAT_CRC); > +} Is that right? This can only return true if V4 support is compiled in, but it should be the other way around - always return true if V4 support is not compiled in. i.e: if (!IS_ENABLED(CONFIG_XFS_SUPPORT_V4)) return true; return mp->m_features & XFS_FEAT_CRC; -Dave.
On Tue, Mar 19, 2024 at 10:59:09AM -0700, Darrick J. Wong wrote: > On Tue, Mar 19, 2024 at 05:19:51PM +1000, Christoph Hellwig wrote: > > Add a strategic IS_ENABLED to let the compiler eliminate the unused > > non-crc code is CONFIG_XFS_SUPPORT_V4 is disabled. > > > > This saves almost 20k worth of .text for my .config: > > > > $ size xfs.o.* > > text data bss dec hex filename > > 1351126 294836 592 1646554 191fda xfs.o.new > > 1371453 294868 592 1666913 196f61 xfs.o.old > > > > Signed-off-by: Christoph Hellwig <hch@lst.de> > > --- > > fs/xfs/xfs_mount.h | 7 ++++++- > > fs/xfs/xfs_super.c | 22 +++++++++++++--------- > > 2 files changed, 19 insertions(+), 10 deletions(-) > > > > diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h > > index e880aa48de68bb..24fe6e7913c49f 100644 > > --- a/fs/xfs/xfs_mount.h > > +++ b/fs/xfs/xfs_mount.h > > @@ -327,6 +327,12 @@ static inline void xfs_add_ ## name (struct xfs_mount *mp) \ > > xfs_sb_version_add ## name(&mp->m_sb); \ > > } > > > > +static inline bool xfs_has_crc(struct xfs_mount *mp) > > +{ > > + return IS_ENABLED(CONFIG_XFS_SUPPORT_V4) && > > + (mp->m_features & XFS_FEAT_CRC); > > Can you save even more text bytes by defining > xfs_has_{nlink,v3inodes,projid32,lazysbcount,pquotino,attr2} to 1? > And I guess defining noattr2 to 0? That sounds like a new __XFS_HAS_V4_FEAT() that has a thrid parameter to define the value when V4 support is not compiled in. e.g. #define __XFS_HAS_V4_FEAT(name, NAME, v5_support) \ static inline bool xfs_has_ ## name (struct xfs_mount *mp) \ { \ if (!IS_ENABLED(CONFIG_XFS_SUPPORT_V4)) \ return v5_support; \ return mp->m_features & XFS_FEAT_ ## NAME; \ } That way we have a single macro that tells us that it is a V4 defined feature, and the documents the support of that feature in V5 filesystems. And when it comes to removing v4 support, we have clear code documentation as to which features we need to remove or make unconditional across the code base. -Dave.
On Wed, Mar 20, 2024 at 08:13:21AM +1100, Dave Chinner wrote: > That sounds like a new __XFS_HAS_V4_FEAT() that has a thrid > parameter to define the value when V4 support is not compiled in. That's exactly what I did yesterday. I'll post the updated version when I find time.
On Wed, Mar 20, 2024 at 08:05:13AM +1100, Dave Chinner wrote: > Is that right? This can only return true if V4 support is compiled > in, but it should be the other way around - always return true if > V4 support is not compiled in. i.e: Yes. I actually also fixed that when I redid the patch. The downside is that despite the additional stubs we actually remove less code now.
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index e880aa48de68bb..24fe6e7913c49f 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -327,6 +327,12 @@ static inline void xfs_add_ ## name (struct xfs_mount *mp) \ xfs_sb_version_add ## name(&mp->m_sb); \ } +static inline bool xfs_has_crc(struct xfs_mount *mp) +{ + return IS_ENABLED(CONFIG_XFS_SUPPORT_V4) && + (mp->m_features & XFS_FEAT_CRC); +} + /* Superblock features */ __XFS_ADD_FEAT(attr, ATTR) __XFS_HAS_FEAT(nlink, NLINK) @@ -341,7 +347,6 @@ __XFS_HAS_FEAT(lazysbcount, LAZYSBCOUNT) __XFS_ADD_FEAT(attr2, ATTR2) __XFS_HAS_FEAT(parent, PARENT) __XFS_ADD_FEAT(projid32, PROJID32) -__XFS_HAS_FEAT(crc, CRC) __XFS_HAS_FEAT(v3inodes, V3INODES) __XFS_HAS_FEAT(pquotino, PQUOTINO) __XFS_HAS_FEAT(ftype, FTYPE) diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 6828c48b15e9bd..7d972e1179255b 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -1580,17 +1580,21 @@ xfs_fs_fill_super( if (error) goto out_free_sb; - /* V4 support is undergoing deprecation. */ - if (!xfs_has_crc(mp)) { -#ifdef CONFIG_XFS_SUPPORT_V4 + /* + * V4 support is undergoing deprecation. + * + * Note: this has to use an open coded m_features check as xfs_has_crc + * always returns false for !CONFIG_XFS_SUPPORT_V4. + */ + if (!(mp->m_features & XFS_FEAT_CRC)) { + if (!IS_ENABLED(CONFIG_XFS_SUPPORT_V4)) { + xfs_warn(mp, + "Deprecated V4 format (crc=0) not supported by kernel."); + error = -EINVAL; + goto out_free_sb; + } xfs_warn_once(mp, "Deprecated V4 format (crc=0) will not be supported after September 2030."); -#else - xfs_warn(mp, - "Deprecated V4 format (crc=0) not supported by kernel."); - error = -EINVAL; - goto out_free_sb; -#endif } /* ASCII case insensitivity is undergoing deprecation. */
Add a strategic IS_ENABLED to let the compiler eliminate the unused non-crc code is CONFIG_XFS_SUPPORT_V4 is disabled. This saves almost 20k worth of .text for my .config: $ size xfs.o.* text data bss dec hex filename 1351126 294836 592 1646554 191fda xfs.o.new 1371453 294868 592 1666913 196f61 xfs.o.old Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/xfs_mount.h | 7 ++++++- fs/xfs/xfs_super.c | 22 +++++++++++++--------- 2 files changed, 19 insertions(+), 10 deletions(-)