Messages in this thread | | | Date | Thu, 16 Mar 2006 16:37:28 -0800 | From | Andrew Morton <> | Subject | Re: [patch] mspec - special memory driver and do_no_pfn handler |
| |
Jes Sorensen <jes@sgi.com> wrote: > > Hi, > > This is an updated version of the mspec driver (special memory > support), formerly known as fetchop. > > With this version I have implemented a do_no_pfn() handler, similar to > the do_no_page() handler but for pages which are not backed by a > struct page.
hm. Is that a superset of ->nopage? Should we be looking at migrating over to ->nopfn, retire ->nopage?
<looks at the ghastly stuff in do_no_page>
Maybe not...
> This avoids the trick used in earlier versions where the > driver was allocating a dumy page returning it back to the > do_no_page() handler which would the free it immediately. Hopefully > this addresses the main concern there were with this driver in the > past. > > The reason for taking the do_no_pfn() approch rather than > remap_pfn_range() is that it needs to benefit from node locality of > the pages on NUMA systems. > > While the driver is currently only used on SN2 hardware, it is placed > in drivers/char as it should be possible and beneficial for other > architectures to implement and use the uncached mode. > > Please let me know if there are any objections or comments etc. to > this approach. If preferred I can split out the do_no_pfn part into a > seperate patch.
That would probably be best.
> +#include <linux/config.h> > +#include <linux/types.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/init.h> > +#include <linux/errno.h> > +#include <linux/miscdevice.h> > +#include <linux/spinlock.h> > +#include <linux/mm.h> > +#include <linux/proc_fs.h> > +#include <linux/vmalloc.h> > +#include <linux/bitops.h> > +#include <linux/string.h> > +#include <linux/slab.h> > +#include <linux/seq_file.h> > +#include <linux/efi.h> > +#include <linux/numa.h> > +#include <asm/page.h> > +#include <asm/pal.h> > +#include <asm/system.h> > +#include <asm/pgtable.h> > +#include <asm/atomic.h> > +#include <asm/tlbflush.h> > +#include <asm/uncached.h> > +#include <asm/sn/addrs.h> > +#include <asm/sn/arch.h> > +#include <asm/sn/mspec.h> > +#include <asm/sn/sn_cpuid.h> > +#include <asm/sn/io.h> > +#include <asm/sn/bte.h> > +#include <asm/sn/shubio.h>
Wow.
> +static inline int > +mspec_zero_block(unsigned long addr, int len) > +{ > + int status; > + > + if (ia64_platform_is("sn2")) {
ia64 uses strcmp() in hotpaths to work out what sort of platform it's running on? Surely someone has cached this info in a __read_mostly integer somewhere?
> +static __inline__ pmd_t *
`inline', please.
> +mspec_get_pmd(struct mm_struct *mm, u64 address)
This function has no callers.
> +static int __init > +mspec_init(void) > +{ > + int ret; > + int nid; > + > + /* > + * The fetchop device only works on SN2 hardware, uncached and cached > + * memory drivers should both be valid on all ia64 hardware > + */ > + if (ia64_platform_is("sn2")) { > + if (is_shub2()) { > + ret = -ENOMEM; > + for_each_online_node(nid) { > + int actual_nid; > + > + scratch_page[nid] = uncached_alloc_page(nid); > + if (scratch_page[nid] == 0) > + goto free_scratch_pages; > + actual_nid = nasid_to_cnodeid(get_node_number(__pa(scratch_page[nid]))); > + if (actual_nid != nid) > + goto free_scratch_pages; > + } > + } > + > + ret = misc_register(&fetchop_miscdev); > + if (ret) { > + printk(KERN_ERR > + "%s: failed to register device %i\n", > + FETCHOP_ID, ret); > + goto free_scratch_pages; > + } > + } > + ret = misc_register(&cached_miscdev); > + if (ret) { > + printk(KERN_ERR "%s: failed to register device %i\n", > + CACHED_ID, ret); > + misc_deregister(&fetchop_miscdev);
You don't know that fetchop_miscdev was registered.
- 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/
| |