lkml.org 
[lkml]   [2016]   [Aug]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RFC PATCH v7 1/7] Restartable sequences system call
    On Tue, 26 Jul 2016, Mathieu Desnoyers wrote:

    > > What problem does this solve?
    >
    > It allows user-space to perform update operations on per-cpu data without
    > requiring heavy-weight atomic operations.


    This is great but seems to indicate that such a facility would be better
    for kernel code instread of user space code.

    > First, prohibiting migration from user-space has been frowned upon
    > by scheduler developers for a long time, and I doubt this mindset will
    > change.

    Note that the task isolation patchset from Chris Metcalf does something
    that goes a long way towards this. If you set strict isolation mode then
    the kernel will terminate the process or notify you if the scheduler
    becomes involved. In some way we are getting that as a side effect.

    Also prohibiting migration is trivial form user space. Just do a taskset
    to a single cpu.

    \
     
     \ /
      Last update: 2016-08-03 21:01    [W:5.082 / U:0.128 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site