Re: [PATCH v4 0/4] percpu: partial chunk depopulation
From: Dennis Zhou
Date: Wed Apr 21 2021 - 14:25:02 EST
On Mon, Apr 19, 2021 at 10:50:43PM +0000, Dennis Zhou wrote:
> This series is a continuation of Roman's series in . It aims to solve
> chunks holding onto free pages by adding a reclaim process to the percpu
> balance work item.
> The main difference is that the nr_empty_pop_pages is now managed at
> time of isolation instead of intermixed. This helps with deciding which
> chunks to free instead of having to interleave returning chunks to
> active duty.
> The allocation priority is as follows:
> 1) appropriate chunk slot increasing until fit
> 2) sidelined chunks
> 3) full free chunks
> The last slot for to_depopulate is never used for allocations.
> A big thanks to Roman for initiating the work and being available for
> iterating on these ideas.
> This patchset contains the following 4 patches:
> 0001 and 0002 are clean ups. 0003 implement partial chunk depopulation
> initially from Roman. 0004 adds a reclaim threshold so we do not need to
> schedule for every page freed.
> This series is on top of percpu$for-5.14 67c2669d69fb.
> diffstats below:
> Dennis Zhou (2):
> percpu: use pcpu_free_slot instead of pcpu_nr_slots - 1
> percpu: use reclaim threshold instead of running for every page
> Roman Gushchin (2):
> percpu: factor out pcpu_check_block_hint()
> percpu: implement partial chunk depopulation
> mm/percpu-internal.h | 5 +
> mm/percpu-km.c | 5 +
> mm/percpu-stats.c | 20 ++--
> mm/percpu-vm.c | 30 ++++++
> mm/percpu.c | 252 ++++++++++++++++++++++++++++++++++++++-----
> 5 files changed, 278 insertions(+), 34 deletions(-)
I've applied this to for-5.14 with 1 modification to the batching
threshold, 4 pages is quite little, so make it 16.