Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-10-02 Thread Paul E. McKenney
On Fri, Oct 02, 2020 at 08:57:46AM +0200, Michal Hocko wrote: > On Thu 01-10-20 09:27:09, Paul E. McKenney wrote: > [...] > > commit ea5c19d21233b5e8d3d06c0d4ecd6be9f2829dc3 > > Author: Paul E. McKenney > > Date: Thu Oct 1 09:24:40 2020 -0700 > > > > kvfree_rcu: Use __GFP_NOMEMALLOC for

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-10-02 Thread Michal Hocko
On Thu 01-10-20 09:27:09, Paul E. McKenney wrote: [...] > commit ea5c19d21233b5e8d3d06c0d4ecd6be9f2829dc3 > Author: Paul E. McKenney > Date: Thu Oct 1 09:24:40 2020 -0700 > > kvfree_rcu: Use __GFP_NOMEMALLOC for single-argument kvfree_rcu() > > This commit applies the

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-10-01 Thread Uladzislau Rezki
On Thu, Oct 01, 2020 at 11:02:20AM +0200, Michal Hocko wrote: > On Wed 30-09-20 16:21:54, Paul E. McKenney wrote: > > On Wed, Sep 30, 2020 at 10:41:39AM +0200, Michal Hocko wrote: > > > On Tue 29-09-20 18:53:27, Paul E. McKenney wrote: > [...] > > > > No argument on it being confusing, and I hope

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-10-01 Thread Paul E. McKenney
On Thu, Oct 01, 2020 at 11:02:20AM +0200, Michal Hocko wrote: > On Wed 30-09-20 16:21:54, Paul E. McKenney wrote: [ . . . ] Hit "send" too soon, apologies... > > > > > > commit 490b638d7c241ac06cee168ccf8688bb8b872478 > >

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-10-01 Thread Paul E. McKenney
On Thu, Oct 01, 2020 at 11:02:20AM +0200, Michal Hocko wrote: > On Wed 30-09-20 16:21:54, Paul E. McKenney wrote: > > On Wed, Sep 30, 2020 at 10:41:39AM +0200, Michal Hocko wrote: > > > On Tue 29-09-20 18:53:27, Paul E. McKenney wrote: > [...] > > > > No argument on it being confusing, and I hope

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-10-01 Thread Michal Hocko
On Wed 30-09-20 16:21:54, Paul E. McKenney wrote: > On Wed, Sep 30, 2020 at 10:41:39AM +0200, Michal Hocko wrote: > > On Tue 29-09-20 18:53:27, Paul E. McKenney wrote: [...] > > > No argument on it being confusing, and I hope that the added header > > > comment helps. But specifically,

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-09-30 Thread Paul E. McKenney
On Wed, Sep 30, 2020 at 10:41:39AM +0200, Michal Hocko wrote: > On Tue 29-09-20 18:53:27, Paul E. McKenney wrote: > > On Tue, Sep 29, 2020 at 02:07:56PM +0200, Michal Hocko wrote: > > > On Mon 28-09-20 16:31:01, paul...@kernel.org wrote: > > > [...] > > > > Apologies for the delay, but today has

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-09-30 Thread Uladzislau Rezki
> > > > What is the point of calling kmalloc for a PAGE_SIZE object? Wouldn't > > > using the page allocator directly be better? > > > > Well, you guys gave me considerable heat about abusing internal allocator > > interfaces, and kmalloc() and kfree() seem to be about as non-internal > > as you

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-09-30 Thread Michal Hocko
On Tue 29-09-20 18:53:27, Paul E. McKenney wrote: > On Tue, Sep 29, 2020 at 02:07:56PM +0200, Michal Hocko wrote: > > On Mon 28-09-20 16:31:01, paul...@kernel.org wrote: > > [...] > > Apologies for the delay, but today has not been boring. > > > > This commit therefore uses preemptible() to

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-09-29 Thread Paul E. McKenney
On Tue, Sep 29, 2020 at 02:07:56PM +0200, Michal Hocko wrote: > On Mon 28-09-20 16:31:01, paul...@kernel.org wrote: > [...] Apologies for the delay, but today has not been boring. > > This commit therefore uses preemptible() to determine whether allocation > > is possible at all for

Re: [PATCH tip/core/rcu 14/15] rcu/tree: Allocate a page when caller is preemptible

2020-09-29 Thread Michal Hocko
On Mon 28-09-20 16:31:01, paul...@kernel.org wrote: [...] > This commit therefore uses preemptible() to determine whether allocation > is possible at all for double-argument kvfree_rcu(). This deserves a comment. Because GFP_ATOMIC is possible for many !preemptible() contexts. It is the