[0/9] memcg: cleanup per-cpu stock

Message

Shakeel Butt March 15, 2025, 5:49 p.m. UTC

This is a cleanup series which is trying to simplify the memcg per-cpu
stock code, particularly it tries to remove unnecessary dependencies on
local_lock of per-cpu memcg stock. The eight patch from Vlastimil
optimizes the charge path by combining the charging and accounting.

This series is based on next-20250314 plus two following patches:

Link: https://lore.kernel.org/all/[e-mail]/
Link: https://lore.kernel.org/all/[e-mail]/

Shakeel Butt (8):
  memcg: remove root memcg check from refill_stock
  memcg: decouple drain_obj_stock from local stock
  memcg: introduce memcg_uncharge
  memcg: manually inline __refill_stock
  memcg: no refilling stock from obj_cgroup_release
  memcg: do obj_cgroup_put inside drain_obj_stock
  memcg: use __mod_memcg_state in drain_obj_stock
  memcg: manually inline replace_stock_objcg

Vlastimil Babka (1):
  memcg: combine slab obj stock charging and accounting

 mm/memcontrol.c | 195 +++++++++++++++++++++++-------------------------
 1 file changed, 95 insertions(+), 100 deletions(-)

Comments

Andrew Morton March 16, 2025, 3:57 a.m. UTC | #1

On Sat, 15 Mar 2025 10:49:21 -0700 Shakeel Butt <[e-mail]> wrote:

> 
> This is a cleanup series which is trying to simplify the memcg per-cpu
> stock code, particularly it tries to remove unnecessary dependencies on
> local_lock of per-cpu memcg stock. The eight patch from Vlastimil
> optimizes the charge path by combining the charging and accounting.
> 
> This series is based on next-20250314 plus two following patches:
> 
> Link: https://lore.kernel.org/all/[e-mail]/
> Link: https://lore.kernel.org/all/[e-mail]/

Unfortunately the bpf tree has been making changes in the same area of
memcontrol.c.  01d37228d331 ("memcg: Use trylock to access memcg
stock_lock.")

Sigh.  We're at -rc7 and I don't think it's worth working around that
for a cleanup series.  So I'm inclined to just defer this series until
the next -rc cycle.

If BPF merges reasonably early in the next merge window then please
promptly send this along and I should be able to squeak it into
6.15-rc1.

Shakeel Butt March 16, 2025, 4:43 a.m. UTC | #2

On Sat, Mar 15, 2025 at 08:57:59PM -0700, Andrew Morton wrote:
> On Sat, 15 Mar 2025 10:49:21 -0700 Shakeel Butt <[e-mail]> wrote:
> 
> > 
> > This is a cleanup series which is trying to simplify the memcg per-cpu
> > stock code, particularly it tries to remove unnecessary dependencies on
> > local_lock of per-cpu memcg stock. The eight patch from Vlastimil
> > optimizes the charge path by combining the charging and accounting.
> > 
> > This series is based on next-20250314 plus two following patches:
> > 
> > Link: https://lore.kernel.org/all/[e-mail]/
> > Link: https://lore.kernel.org/all/[e-mail]/
> 
> Unfortunately the bpf tree has been making changes in the same area of
> memcontrol.c.  01d37228d331 ("memcg: Use trylock to access memcg
> stock_lock.")
> 
> Sigh.  We're at -rc7 and I don't think it's worth working around that
> for a cleanup series.  So I'm inclined to just defer this series until
> the next -rc cycle.
> 
> If BPF merges reasonably early in the next merge window then please
> promptly send this along and I should be able to squeak it into
> 6.15-rc1.
> 

Seems reasonable to me and thanks for taking a look.

Alexei Starovoitov March 16, 2025, 3:59 p.m. UTC | #3

On Sat, Mar 15, 2025 at 08:57:59PM -0700, Andrew Morton wrote:
> On Sat, 15 Mar 2025 10:49:21 -0700 Shakeel Butt <[e-mail]> wrote:
> 
> > 
> > This is a cleanup series which is trying to simplify the memcg per-cpu
> > stock code, particularly it tries to remove unnecessary dependencies on
> > local_lock of per-cpu memcg stock. The eight patch from Vlastimil
> > optimizes the charge path by combining the charging and accounting.
> > 
> > This series is based on next-20250314 plus two following patches:
> > 
> > Link: https://lore.kernel.org/all/[e-mail]/
> > Link: https://lore.kernel.org/all/[e-mail]/
> 
> Unfortunately the bpf tree has been making changes in the same area of
> memcontrol.c.  01d37228d331 ("memcg: Use trylock to access memcg
> stock_lock.")
> 
> Sigh.  We're at -rc7 and I don't think it's worth working around that
> for a cleanup series.  So I'm inclined to just defer this series until
> the next -rc cycle.
> 
> If BPF merges reasonably early in the next merge window then please
> promptly send this along and I should be able to squeak it into
> 6.15-rc1.

Ohh. I didn't realize that try_alloc changes are causing so much trouble.
Sorry about that.

Andrew,

could you please instead take bpf-next.git try_alloc_pages branch
into your tree and resolve two trivial conflicts:
1. https://lore.kernel.org/bpf/[e-mail]/
2. https://lore.kernel.org/bpf/[e-mail]/
There are 7 commits there.
You can also squash Vlastimil's fix
"Fix the flipped condition in gfpflags_allow_spinning" into 
"Introduce try_alloc_pages" patch or keep everything as-is.

I'll drop it from bpf-next right after.

Then Shakeel can rebase/resend his set without conflicts and everything
will be nicely ready for the merge window.

I'll defer other bpf side things to after merge window when trees converge.

Thanks!