From 1c94984396dc7bc40b4f6899674eaa41f29a4f6e Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Thu, 1 Mar 2018 00:19:21 +0100 Subject: vfs: make sure struct filename->iname is word-aligned I noticed that offsetof(struct filename, iname) is actually 28 on 64 bit platforms, so we always pass an unaligned pointer to strncpy_from_user. This is mostly a problem for those 64 bit platforms without HAVE_EFFICIENT_UNALIGNED_ACCESS, but even on x86_64, unaligned accesses carry a penalty. A user-space microbenchmark doing nothing but strncpy_from_user from the same (aligned) source string runs about 5% faster when the destination is aligned. That number increases to 20% when the string is long enough (~32 bytes) that we cross a cache line boundary - that's for example the case for about half the files a "git status" in a kernel tree ends up stat'ing. This won't make any real-life workloads 5%, or even 1%, faster, but path lookup is common enough that cutting even a few cycles should be worthwhile. So ensure we always pass an aligned destination pointer to strncpy_from_user. Instead of explicit padding, simply swap the refcnt and aname members, as suggested by Al Viro. Signed-off-by: Rasmus Villemoes Signed-off-by: Al Viro --- include/linux/fs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/fs.h b/include/linux/fs.h index 2a815560fda0..d7b2caadb292 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2380,8 +2380,8 @@ struct audit_names; struct filename { const char *name; /* pointer to actual string */ const __user char *uptr; /* original userland pointer */ - struct audit_names *aname; int refcnt; + struct audit_names *aname; const char iname[]; }; -- cgit v1.2.3 From 0e11f6443f522f89509495b13ef1f3745640144d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 21 Feb 2018 07:54:49 -0800 Subject: fs: move I_DIRTY_INODE to fs.h And use it in a few more places rather than opencoding the values. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/ext4/inode.c | 4 ++-- fs/fs-writeback.c | 9 +++------ fs/gfs2/super.c | 2 +- include/linux/fs.h | 3 ++- 4 files changed, 8 insertions(+), 10 deletions(-) (limited to 'include/linux') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c94780075b04..6d2a18991fcb 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5032,12 +5032,12 @@ static int other_inode_match(struct inode * inode, unsigned long ino, if ((inode->i_ino != ino) || (inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW | - I_DIRTY_SYNC | I_DIRTY_DATASYNC)) || + I_DIRTY_INODE)) || ((inode->i_state & I_DIRTY_TIME) == 0)) return 0; spin_lock(&inode->i_lock); if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW | - I_DIRTY_SYNC | I_DIRTY_DATASYNC)) == 0) && + I_DIRTY_INODE)) == 0) && (inode->i_state & I_DIRTY_TIME)) { struct ext4_inode_info *ei = EXT4_I(inode); diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index d4d04fee568a..1280f915079b 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1343,7 +1343,7 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) dirty = inode->i_state & I_DIRTY; if (inode->i_state & I_DIRTY_TIME) { - if ((dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) || + if ((dirty & I_DIRTY_INODE) || wbc->sync_mode == WB_SYNC_ALL || unlikely(inode->i_state & I_DIRTY_TIME_EXPIRED) || unlikely(time_after(jiffies, @@ -2112,7 +2112,6 @@ static noinline void block_dump___mark_inode_dirty(struct inode *inode) */ void __mark_inode_dirty(struct inode *inode, int flags) { -#define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC) struct super_block *sb = inode->i_sb; int dirtytime; @@ -2122,7 +2121,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) * Don't do this for I_DIRTY_PAGES - that doesn't actually * dirty the inode itself */ - if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_TIME)) { + if (flags & (I_DIRTY_INODE | I_DIRTY_TIME)) { trace_writeback_dirty_inode_start(inode, flags); if (sb->s_op->dirty_inode) @@ -2197,7 +2196,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) if (dirtytime) inode->dirtied_time_when = jiffies; - if (inode->i_state & (I_DIRTY_INODE | I_DIRTY_PAGES)) + if (inode->i_state & I_DIRTY) dirty_list = &wb->b_dirty; else dirty_list = &wb->b_dirty_time; @@ -2221,8 +2220,6 @@ void __mark_inode_dirty(struct inode *inode, int flags) } out_unlock_inode: spin_unlock(&inode->i_lock); - -#undef I_DIRTY_INODE } EXPORT_SYMBOL(__mark_inode_dirty); diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 620be0521866..cf5c7f3080d2 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -800,7 +800,7 @@ static void gfs2_dirty_inode(struct inode *inode, int flags) int need_endtrans = 0; int ret; - if (!(flags & (I_DIRTY_DATASYNC|I_DIRTY_SYNC))) + if (!(flags & I_DIRTY_INODE)) return; if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) return; diff --git a/include/linux/fs.h b/include/linux/fs.h index d7b2caadb292..00da24bc0350 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2014,7 +2014,8 @@ static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp) #define I_WB_SWITCH (1 << 13) #define I_OVL_INUSE (1 << 14) -#define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES) +#define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC) +#define I_DIRTY (I_DIRTY_INODE | I_DIRTY_PAGES) #define I_DIRTY_ALL (I_DIRTY | I_DIRTY_TIME) extern void __mark_inode_dirty(struct inode *, int); -- cgit v1.2.3