Re: [PATCH 87/87] fs: move i_blocks up a few places in struct inode
From: Amir Goldstein <amir73il@gmail.com>
Date: 2023-09-28 11:35:35
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On Thu, Sep 28, 2023 at 2:06 PM Jeff Layton [off-list ref] wrote:
The recent change to use discrete integers instead of struct timespec64 in struct inode shaved 8 bytes off of it, but it also moves the i_lock into the previous cacheline, away from the fields that it protects. Move i_blocks up above the i_lock, which moves the new 4 byte hole to just after the timestamps, without changing the size of the structure.
Instead of creating an implicit hole, can you please move i_generation to fill the 4 bytes hole. It makes sense in the same cache line with i_ino and I could use the vacant 4 bytes hole above i_fsnotify_mask to expand the mask to 64bit (the 32bit event mask space is running out). Thanks, Amir.
quoted hunk ↗ jump to hunk
Signed-off-by: Jeff Layton <jlayton@kernel.org> --- include/linux/fs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/include/linux/fs.h b/include/linux/fs.h index de902ff2938b..3e0fe0f52e7c 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h@@ -677,11 +677,11 @@ struct inode { u32 i_atime_nsec; u32 i_mtime_nsec; u32 i_ctime_nsec; + blkcnt_t i_blocks; spinlock_t i_lock; /* i_blocks, i_bytes, maybe i_size */ unsigned short i_bytes; u8 i_blkbits; u8 i_write_hint; - blkcnt_t i_blocks; #ifdef __NEED_I_SIZE_ORDERED seqcount_t i_size_seqcount; --2.41.0