Re: [patch 1/8] fdmap v2 - fdmap core

[Eric Dumazet <dada1@cosmosbay.com>]

Eric Dumazet a écrit :
> 
> struct fd_map {
>     /*
>      * read mostly part
>      */
>     unsigned int base;   /* 0x00 */
>     unsigned int size;   /* 0x04 */
>     struct list_head slist; /* 0x08 */
>     struct list_head *slots; /* 0x18 */
>     unsigned long *map; /* 0x28 */
>     void (*freecb)(void *, struct fd_map *); /* 0x30 */
>     void *freecb_priv; /* 0x38 */
> 
>     /*
>      * written part on a separate cache line in SMP
>      */
>     unsigned int fdnext ____cacheline_aligned_in_smp; /* 0x40 */
> 
>     struct fd_map *next;  /* 0x48 */
>     struct rcu_head rcu; /* 0x50 */
> };

Well, offsets are wrong but layout OK

struct fd_map {
     /*
      * read mostly part
      */
     unsigned int base;   /* 0x00 */
     unsigned int size;   /* 0x04 */
     struct list_head slist; /* 0x08 */
     struct list_head *slots; /* 0x18 */
     unsigned long *map; /* 0x20 */
     void (*freecb)(void *, struct fd_map *); /* 0x28 */
     void *freecb_priv; /* 0x30 */
	/* one 8 bytes hole */

     /*
      * written part on a separate cache line in SMP
      */
     unsigned int fdnext ____cacheline_aligned_in_smp; /* 0x40 */

     struct fd_map *next;  /* 0x48 */
     struct rcu_head rcu; /* 0x50 */
}; /* size 0x60 , aligned to 0x80 */