On Wed, Aug 16, 2017 at 09:35:11AM -0700, Dan Williams wrote: > On Wed, Aug 16, 2017 at 4:15 AM, Kirill A. Shutemov > <kirill@xxxxxxxxxxxxx> wrote: > > On Wed, Aug 16, 2017 at 12:44:22AM -0700, Dan Williams wrote: > >> diff --git a/include/linux/mman.h b/include/linux/mman.h > >> index c8367041fafd..0e1de42c836f 100644 > >> --- a/include/linux/mman.h > >> +++ b/include/linux/mman.h > >> @@ -7,6 +7,40 @@ > >> #include <linux/atomic.h> > >> #include <uapi/linux/mman.h> > >> > >> +#ifndef MAP_32BIT > >> +#define MAP_32BIT 0 > >> +#endif > >> +#ifndef MAP_HUGE_2MB > >> +#define MAP_HUGE_2MB 0 > >> +#endif > >> +#ifndef MAP_HUGE_1GB > >> +#define MAP_HUGE_1GB 0 > >> +#endif > >> + > >> +/* > >> + * The historical set of flags that all mmap implementations implicitly > >> + * support when file_operations.mmap_supported_mask is zero. > >> + */ > >> +#define LEGACY_MAP_SUPPORTED_MASK (MAP_SHARED \ > >> + | MAP_PRIVATE \ > >> + | MAP_FIXED \ > >> + | MAP_ANONYMOUS \ > >> + | MAP_UNINITIALIZED \ > >> + | MAP_GROWSDOWN \ > >> + | MAP_DENYWRITE \ > >> + | MAP_EXECUTABLE \ > >> + | MAP_LOCKED \ > >> + | MAP_NORESERVE \ > >> + | MAP_POPULATE \ > >> + | MAP_NONBLOCK \ > >> + | MAP_STACK \ > >> + | MAP_HUGETLB \ > >> + | MAP_32BIT \ > >> + | MAP_HUGE_2MB \ > >> + | MAP_HUGE_1GB) > >> + > >> +#define MAP_SUPPORTED_MASK (LEGACY_MAP_SUPPORTED_MASK) > >> + > >> extern int sysctl_overcommit_memory; > >> extern int sysctl_overcommit_ratio; > >> extern unsigned long sysctl_overcommit_kbytes; > > > > Since we looking into mmap(2) ABI, maybe we should consider re-defining > > MAP_DENYWRITE and MAP_EXECUTABLE as 0 in hope that we would be able to > > re-use these bits in the future? These flags are ignored now anyway. > > Yes, we can make these -EOPNOTSUPP in the new syscall. You cannot detect them, if we would redefine them as 0. :) -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
