Hi Richard, On 08/18/2016 08:17 AM, Richard Weinberger wrote: > On Wed, Aug 17, 2016 at 1:12 PM, Christopher Covington > <c...@codeaurora.org> wrote: >> >> >> On August 17, 2016 6:30:06 AM EDT, Catalin Marinas <catalin.mari...@arm.com> >> wrote: >>> On Tue, Aug 16, 2016 at 02:32:29PM -0400, Christopher Covington wrote: >>>> Some userspace applications need to know the maximum virtual address >>> they can >>>> use (TASK_SIZE). >>> >>> Just curious, what are the cases needing TASK_SIZE in user space? >> >> Checkpoint/Restore In Userspace and the Mozilla Javascript Engine >> https://bugzilla.mozilla.org/show_bug.cgi?id=1143022 are the specific cases >> I've run into. I've heard LuaJIT might have a similar situation. In general >> I think making allocations from the top down is a shortcut for finding a >> large unused region of memory. > > I think this makes sense for all archs. > At lest UserModeLinux on x86 also needs to know bottom and top > addresses of the usable > address space. > Currently it figures by scanning and catching SIGSEGV.
For the bottom, can you use /proc/sys/vm/mmap_min_addr? Cov -- Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
