On Tue, Sep 27, 2011 at 08:26:29AM -0400, Ohad Ben-Cohen wrote: > > With an unsigned long you can use plain and fast bit_ops instead of the > > full bitmap functions. > > Not sure I follow; the only bit operation I'm using while mapping is > find_next_bit() (which is a bitops.h method). > > What other faster variant are you referring to ? You pass a pointer to an unsigned long for the page-size bitmap. This allows to use an array of unsigned long. But a single unsigned long is sufficient and you can use functions like ffs() and fls() together with shifting. These functions often translate to a single intruction in the binary. The find_next_bit function has much more overhead because it needs to handle the array-of-ulong case. Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
