Messages in this thread | | | Date | Mon, 27 Oct 2014 11:18:06 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH RESEND 2/4] cpuset: simplify cpuset_node_allowed API |
| |
On Mon, Oct 20, 2014 at 03:50:30PM +0400, Vladimir Davydov wrote: > Current cpuset API for checking if a zone/node is allowed to allocate > from looks rather awkward. We have hardwall and softwall versions of > cpuset_node_allowed with the softwall version doing literally the same > as the hardwall version if __GFP_HARDWALL is passed to it in gfp flags. > If it isn't, the softwall version may check the given node against the > enclosing hardwall cpuset, which it needs to take the callback lock to > do. > > Such a distinction was introduced by commit 02a0e53d8227 ("cpuset: > rework cpuset_zone_allowed api"). Before, we had the only version with > the __GFP_HARDWALL flag determining its behavior. The purpose of the > commit was to avoid sleep-in-atomic bugs when someone would mistakenly > call the function without the __GFP_HARDWALL flag for an atomic > allocation. The suffixes introduced were intended to make the callers > think before using the function. > > However, since the callback lock was converted from mutex to spinlock by > the previous patch, the softwall check function cannot sleep, and these > precautions are no longer necessary. > > So let's simplify the API back to the single check. > > Suggested-by: David Rientjes <rientjes@google.com> > Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> > Acked-by: Christoph Lameter <cl@linux.com> > Acked-by: Zefan Li <lizefan@huawei.com>
Applied 1-2 to cgroup/for-3.19-cpuset-api-simplification which contains only these two patches on top of v3.18-rc2 and will stay stable. sl[au]b trees can pull it in or I can take the other two patches too. Please let me know how the other two should be routed.
Thanks.
-- tejun
| |