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Message-Id: <20231018-mgtime-v1-1-4a7a97b1f482@kernel.org>
Date: Wed, 18 Oct 2023 13:41:08 -0400
From: Jeff Layton <jlayton@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>,
John Stultz <jstultz@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Stephen Boyd <sboyd@...nel.org>,
Chandan Babu R <chandan.babu@...cle.com>,
"Darrick J. Wong" <djwong@...nel.org>,
Dave Chinner <david@...morbit.com>,
Theodore Ts'o <tytso@....edu>,
Andreas Dilger <adilger.kernel@...ger.ca>,
Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>,
Hugh Dickins <hughd@...gle.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Amir Goldstein <amir73il@...il.com>, Jan Kara <jack@...e.de>,
David Howells <dhowells@...hat.com>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-xfs@...r.kernel.org, linux-ext4@...r.kernel.org,
linux-btrfs@...r.kernel.org, linux-mm@...ck.org,
linux-nfs@...r.kernel.org, Jeff Layton <jlayton@...nel.org>
Subject: [PATCH RFC 1/9] fs: switch timespec64 fields in inode to discrete
integers
This shaves 8 bytes off struct inode with a garden-variety Fedora
Kconfig, but it moves the i_lock into the previous cacheline, away from
the fields it protects. To remedy that, move the i_generation just after
the nanosecond fields, which moves the 4 byte hole down next to
i_fsnotify_mask.
Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
Suggested-by: Amir Goldstein <amir73il@...il.com>
Signed-off-by: Jeff Layton <jlayton@...nel.org>
---
include/linux/fs.h | 56 +++++++++++++++++++++++++++++++-----------------------
1 file changed, 32 insertions(+), 24 deletions(-)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cc29518517f7..78786c1c32fd 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -671,9 +671,13 @@ struct inode {
};
dev_t i_rdev;
loff_t i_size;
- struct timespec64 __i_atime;
- struct timespec64 __i_mtime;
- struct timespec64 __i_ctime; /* use inode_*_ctime accessors! */
+ time64_t i_atime_sec;
+ time64_t i_mtime_sec;
+ time64_t i_ctime_sec;
+ u32 i_atime_nsec;
+ u32 i_mtime_nsec;
+ u32 i_ctime_nsec;
+ u32 i_generation;
spinlock_t i_lock; /* i_blocks, i_bytes, maybe i_size */
unsigned short i_bytes;
u8 i_blkbits;
@@ -730,10 +734,10 @@ struct inode {
unsigned i_dir_seq;
};
- __u32 i_generation;
#ifdef CONFIG_FSNOTIFY
__u32 i_fsnotify_mask; /* all events this inode cares about */
+ /* 32bit hole reserved for expanding i_fsnotify_mask to 64bit */
struct fsnotify_mark_connector __rcu *i_fsnotify_marks;
#endif
@@ -1513,23 +1517,27 @@ struct timespec64 inode_set_ctime_current(struct inode *inode);
static inline time64_t inode_get_atime_sec(const struct inode *inode)
{
- return inode->__i_atime.tv_sec;
+ return inode->i_atime_sec;
}
static inline long inode_get_atime_nsec(const struct inode *inode)
{
- return inode->__i_atime.tv_nsec;
+ return inode->i_atime_nsec;
}
static inline struct timespec64 inode_get_atime(const struct inode *inode)
{
- return inode->__i_atime;
+ struct timespec64 ts = { .tv_sec = inode_get_atime_sec(inode),
+ .tv_nsec = inode_get_atime_nsec(inode) };
+
+ return ts;
}
static inline struct timespec64 inode_set_atime_to_ts(struct inode *inode,
struct timespec64 ts)
{
- inode->__i_atime = ts;
+ inode->i_atime_sec = ts.tv_sec;
+ inode->i_atime_nsec = ts.tv_nsec;
return ts;
}
@@ -1538,28 +1546,32 @@ static inline struct timespec64 inode_set_atime(struct inode *inode,
{
struct timespec64 ts = { .tv_sec = sec,
.tv_nsec = nsec };
+
return inode_set_atime_to_ts(inode, ts);
}
static inline time64_t inode_get_mtime_sec(const struct inode *inode)
{
- return inode->__i_mtime.tv_sec;
+ return inode->i_mtime_sec;
}
static inline long inode_get_mtime_nsec(const struct inode *inode)
{
- return inode->__i_mtime.tv_nsec;
+ return inode->i_mtime_nsec;
}
static inline struct timespec64 inode_get_mtime(const struct inode *inode)
{
- return inode->__i_mtime;
+ struct timespec64 ts = { .tv_sec = inode_get_mtime_sec(inode),
+ .tv_nsec = inode_get_mtime_nsec(inode) };
+ return ts;
}
static inline struct timespec64 inode_set_mtime_to_ts(struct inode *inode,
struct timespec64 ts)
{
- inode->__i_mtime = ts;
+ inode->i_mtime_sec = ts.tv_sec;
+ inode->i_mtime_nsec = ts.tv_nsec;
return ts;
}
@@ -1573,34 +1585,30 @@ static inline struct timespec64 inode_set_mtime(struct inode *inode,
static inline time64_t inode_get_ctime_sec(const struct inode *inode)
{
- return inode->__i_ctime.tv_sec;
+ return inode->i_ctime_sec;
}
static inline long inode_get_ctime_nsec(const struct inode *inode)
{
- return inode->__i_ctime.tv_nsec;
+ return inode->i_ctime_nsec;
}
static inline struct timespec64 inode_get_ctime(const struct inode *inode)
{
- return inode->__i_ctime;
+ struct timespec64 ts = { .tv_sec = inode_get_ctime_sec(inode),
+ .tv_nsec = inode_get_ctime_nsec(inode) };
+
+ return ts;
}
static inline struct timespec64 inode_set_ctime_to_ts(struct inode *inode,
struct timespec64 ts)
{
- inode->__i_ctime = ts;
+ inode->i_ctime_sec = ts.tv_sec;
+ inode->i_ctime_nsec = ts.tv_nsec;
return ts;
}
-/**
- * inode_set_ctime - set the ctime in the inode
- * @inode: inode in which to set the ctime
- * @sec: tv_sec value to set
- * @nsec: tv_nsec value to set
- *
- * Set the ctime in @inode to { @sec, @nsec }
- */
static inline struct timespec64 inode_set_ctime(struct inode *inode,
time64_t sec, long nsec)
{
--
2.41.0
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