[EMAIL PROTECTED] a écrit :

--- linux-2.6.21-rc7.orig/include/linux/fs.h    2007-04-24 11:31:49.000000000 
-0700
+++ linux-2.6.21-rc7/include/linux/fs.h 2007-04-24 11:37:21.000000000 -0700
@@ -435,6 +435,11 @@ struct address_space {
        struct inode            *host;          /* owner: inode, block_device */
        struct radix_tree_root  page_tree;      /* radix tree of all pages */
        rwlock_t                tree_lock;      /* and rwlock protecting it */
+#ifdef CONFIG_LARGE_BLOCKSIZE
+       unsigned int            order;          /* Page order of the pages in 
here */
+       unsigned int            shift;          /* Shift of index */
+       loff_t                  offset_mask;    /* Mask to get to offset bits */
+#endif
        unsigned int            i_mmap_writable;/* count VM_SHARED mappings */
        struct prio_tree_root   i_mmap;         /* tree of private and shared 
mappings */
        struct list_head        i_mmap_nonlinear;/*list VM_NONLINEAR mappings */

Some comments about this :

1) not optimal placement on 64bits arches (it creates one hole before i_mmap_writeable)

2) sizeof(struct address_space) is an issue, given it is included in every inode, even sockets or pipes.

-> 2.1) Do we really need 32 bits for 'order' and 'shift'
-> 2.2) Do we really need a 64bits offset_mask since it's a trivial arithmetic from 'shift' (or 'order') ?

BTW, I presume splice() is not yet supported ? If yes, each pipe could hold 16 'big pages' so we probably can hit some DOS condition sooner...


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