# endif /* __KERNEL__ */
-/*
- * Enabling BIO_VMERGE_BOUNDARY forces us to turn off I/O MMU bypassing. It is said that
- * BIO-level virtual merging can give up to 4% performance boost (not verified for ia64).
- * On the other hand, we know that I/O MMU bypassing gives ~8% performance improvement on
- * SPECweb-like workloads on zx1-based machines. Thus, for now we favor I/O MMU bypassing
- * over BIO-level virtual merging.
- */
-extern unsigned long ia64_max_iommu_merge_mask;
-#if 1
-#define BIO_VMERGE_BOUNDARY 0
-#else
-/*
- * It makes no sense at all to have this BIO_VMERGE_BOUNDARY macro here. Should be
- * replaced by dma_merge_mask() or something of that sort. Note: the only way
- * BIO_VMERGE_BOUNDARY is used is to mask off bits. Effectively, our definition gets
- * expanded into:
- *
- * addr & ((ia64_max_iommu_merge_mask + 1) - 1) == (addr & ia64_max_iommu_vmerge_mask)
- *
- * which is precisely what we want.
- */
-#define BIO_VMERGE_BOUNDARY (ia64_max_iommu_merge_mask + 1)
-#endif
-
#endif /* _ASM_IA64_IO_H */