Messages in this thread | | | Date | Wed, 25 Apr 2007 01:00:46 +0200 | From | Eric Dumazet <> | Subject | Re: [08/17] Define functions for page cache handling |
| |
clameter@sgi.com 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...
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |