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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-11-18 23:54:26 +08:00
linux-next/include
Arnaldo Carvalho de Melo 12d40e43d2 [PATCH] Save some bytes in struct inode
[acme@newtoy net-2.6.20]$ pahole --cacheline 64 fs/inode.o inode
/* /pub/scm/linux/kernel/git/acme/net-2.6.20/include/linux/dcache.h:86 */
struct inode {
        struct hlist_node          i_hash;               /*     0     8 */
        struct list_head           i_list;               /*     8     8 */
        struct list_head           i_sb_list;            /*    16     8 */
        struct list_head           i_dentry;             /*    24     8 */
        long unsigned int          i_ino;                /*    32     4 */
        atomic_t                   i_count;              /*    36     4 */
        umode_t                    i_mode;               /*    40     2 */

        /* XXX 2 bytes hole, try to pack */

        unsigned int               i_nlink;              /*    44     4 */
        uid_t                      i_uid;                /*    48     4 */
        gid_t                      i_gid;                /*    52     4 */
        dev_t                      i_rdev;               /*    56     4 */
        loff_t                     i_size;               /*    60     8 */
        struct timespec            i_atime;              /*    68     8 */
        struct timespec            i_mtime;              /*    76     8 */
        struct timespec            i_ctime;              /*    84     8 */
        unsigned int               i_blkbits;            /*    92     4 */
        long unsigned int          i_version;            /*    96     4 */
        blkcnt_t                   i_blocks;             /*   100     4 */
        short unsigned int         i_bytes;              /*   104     2 */

        /* XXX 2 bytes hole, try to pack */

        spinlock_t                 i_lock;               /*   108    40 */
        struct mutex               i_mutex;              /*   148    76 */
        struct rw_semaphore        i_alloc_sem;          /*   224    64 */
        struct inode_operations *  i_op;                 /*   288     4 */
        const struct file_operations  * i_fop;           /*   292     4 */
        struct super_block *       i_sb;                 /*   296     4 */
        struct file_lock *         i_flock;              /*   300     4 */
        struct address_space *     i_mapping;            /*   304     4 */
        struct address_space       i_data;               /*   308   188 */
        struct list_head           i_devices;            /*   496     8 */
        union                      ;                     /*   504     4 */
        int                        i_cindex;             /*   508     4 */
        __u32                      i_generation;         /*   512     4 */
        /* ---------- cacheline 8 boundary ---------- */
        long unsigned int          i_dnotify_mask;       /*   516     4 */
        struct dnotify_struct *    i_dnotify;            /*   520     4 */
        struct list_head           inotify_watches;      /*   524     8 */
        struct mutex               inotify_mutex;        /*   532    76 */
        long unsigned int          i_state;              /*   608     4 */
        long unsigned int          dirtied_when;         /*   612     4 */
        unsigned int               i_flags;              /*   616     4 */
        atomic_t                   i_writecount;         /*   620     4 */
        void *                     i_security;           /*   624     4 */
        void *                     i_private;            /*   628     4 */
}; /* size: 632, sum members: 628, holes: 2, sum holes: 4 */

[acme@newtoy net-2.6.20]$

So just moving i_mode to after i_bytes we save 4 bytes by nuking both holes:

[acme@newtoy net-2.6.20]$ codiff -V /tmp/inode.o.before fs/inode.o
/pub/scm/linux/kernel/git/acme/net-2.6.20/fs/inode.c:
  struct inode |   -4
    i_mode;
     from: umode_t               /*    40(0)     2(0) */
     to:   umode_t               /*   102(0)     2(0) */
 1 struct changed
[acme@newtoy net-2.6.20]$

I've prunned all the other offset changes, only this one is of interest here.

So now we have:

[acme@newtoy net-2.6.20]$ pahole --cacheline 64 ../OUTPUT/qemu/net-2.6.20/fs/inode.o inode
/* /pub/scm/linux/kernel/git/acme/net-2.6.20/include/linux/dcache.h:86 */
struct inode {
        struct hlist_node          i_hash;               /*     0     8 */
        struct list_head           i_list;               /*     8     8 */
        struct list_head           i_sb_list;            /*    16     8 */
        struct list_head           i_dentry;             /*    24     8 */
        long unsigned int          i_ino;                /*    32     4 */
        atomic_t                   i_count;              /*    36     4 */
        unsigned int               i_nlink;              /*    40     4 */
        uid_t                      i_uid;                /*    44     4 */
        gid_t                      i_gid;                /*    48     4 */
        dev_t                      i_rdev;               /*    52     4 */
        loff_t                     i_size;               /*    56     8 */
        /* ---------- cacheline 1 boundary ---------- */
        struct timespec            i_atime;              /*    64     8 */
        struct timespec            i_mtime;              /*    72     8 */
        struct timespec            i_ctime;              /*    80     8 */
        unsigned int               i_blkbits;            /*    88     4 */
        long unsigned int          i_version;            /*    92     4 */
        blkcnt_t                   i_blocks;             /*    96     4 */
        short unsigned int         i_bytes;              /*   100     2 */
        umode_t                    i_mode;               /*   102     2 */
        spinlock_t                 i_lock;               /*   104    40 */
        struct mutex               i_mutex;              /*   144    76 */
        struct rw_semaphore        i_alloc_sem;          /*   220    64 */
        struct inode_operations *  i_op;                 /*   284     4 */
        const struct file_operations  * i_fop;           /*   288     4 */
        struct super_block *       i_sb;                 /*   292     4 */
        struct file_lock *         i_flock;              /*   296     4 */
        struct address_space *     i_mapping;            /*   300     4 */
        struct address_space       i_data;               /*   304   188 */
        struct list_head           i_devices;            /*   492     8 */
        union                      ;                     /*   500     4 */
        int                        i_cindex;             /*   504     4 */
        __u32                      i_generation;         /*   508     4 */
        /* ---------- cacheline 8 boundary ---------- */
        long unsigned int          i_dnotify_mask;       /*   512     4 */
        struct dnotify_struct *    i_dnotify;            /*   516     4 */
        struct list_head           inotify_watches;      /*   520     8 */
        struct mutex               inotify_mutex;        /*   528    76 */
        long unsigned int          i_state;              /*   604     4 */
        long unsigned int          dirtied_when;         /*   608     4 */
        unsigned int               i_flags;              /*   612     4 */
        atomic_t                   i_writecount;         /*   616     4 */
        void *                     i_security;           /*   620     4 */
        void *                     i_private;            /*   624     4 */
}; /* size: 628 */

[acme@newtoy net-2.6.20]$

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:43 -08:00
..
acpi [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
asm-alpha [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-arm [PATCH] Add struct dev pointer to dma_is_consistent() 2006-12-07 08:39:41 -08:00
asm-arm26 [PATCH] remove kernel syscalls 2006-12-07 08:39:37 -08:00
asm-avr32 [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-cris [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-frv [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-generic [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-h8300 [PATCH] remove kernel syscalls 2006-12-07 08:39:37 -08:00
asm-i386 [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-ia64 [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-m32r [PATCH] remove kernel syscalls 2006-12-07 08:39:37 -08:00
asm-m68k [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-m68knommu [PATCH] remove kernel syscalls 2006-12-07 08:39:37 -08:00
asm-mips [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-parisc [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-powerpc [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-ppc [PATCH] mm: pagefault_{disable,enable}() 2006-12-07 08:39:21 -08:00
asm-s390 [PATCH] remove kernel syscalls 2006-12-07 08:39:37 -08:00
asm-sh [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-sh64 [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-sparc [PATCH] remove kernel syscalls 2006-12-07 08:39:37 -08:00
asm-sparc64 [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-um [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-v850 [PATCH] remove kernel syscalls 2006-12-07 08:39:37 -08:00
asm-x86_64 [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
asm-xtensa [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
crypto [CRYPTO] digest: Added user API for new hash type 2006-09-21 11:46:17 +10:00
keys
linux [PATCH] Save some bytes in struct inode 2006-12-07 08:39:43 -08:00
math-emu
media V4L/DVB (4666): Ensure the WM8775 driver is loaded generically for any board. 2006-10-03 15:13:48 -03:00
mtd Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2006-10-01 17:55:53 +01:00
net [PATCH] lockdep: annotate nfs/nfsd in-kernel sockets 2006-12-07 08:39:30 -08:00
pcmcia [PATCH] pcmcia: multifunction card handling fixes 2006-12-04 20:09:15 -05:00
rdma IB/cm: Fix automatic path migration support 2006-11-29 15:33:10 -08:00
rxrpc
scsi [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
sound Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2006-12-05 17:01:28 +00:00
video fix file specification in comments 2006-10-03 23:01:26 +02:00
Kbuild [HEADERS] One line per header in Kbuild files to reduce conflicts 2006-09-19 12:43:58 +01:00