Re: [PATCH v2 0/5] mm: support parallel free of memory

From	Michal Hocko <mhocko@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 0/5] mm: support parallel free of memory
Date	2017-03-15 15:30 +0100
Message-ID	<tli65-po-1@gated-at.bofh.it> (permalink)
References	<tld6q-5vn-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed 15-03-17 16:59:59, Aaron Lu wrote:
[...]
> The proposed parallel free did this: if the process has many pages to be
> freed, accumulate them in these struct mmu_gather_batch(es) one after
> another till 256K pages are accumulated. Then take this singly linked
> list starting from tlb->local.next off struct mmu_gather *tlb and free
> them in a worker thread. The main thread can return to continue zap
> other pages(after freeing pages pointed by tlb->local.pages).

I didn't have a look at the implementation yet but there are two
concerns that raise up from this description. Firstly how are we going
to tune the number of workers. I assume there will be some upper bound
(one of the patch subject mentions debugfs for tuning) and secondly
if we offload the page freeing to the worker then the original context
can consume much more cpu cycles than it was configured via cpu
controller. How are we going to handle that? Or is this considered
acceptable?
-- 
Michal Hocko
SUSE Labs

Thread

[PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-15 10:10 +0100
  [PATCH v2 2/5] mm: parallel free pages Aaron Lu <aaron.lu@intel.com> - 2017-03-15 10:10 +0100
    Re: [PATCH v2 2/5] mm: parallel free pages "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2017-03-15 10:50 +0100
      Re: [PATCH v2 2/5] mm: parallel free pages Aaron Lu <aaron.lu@intel.com> - 2017-03-15 13:00 +0100
  Re: [PATCH v2 0/5] mm: support parallel free of memory Michal Hocko <mhocko@kernel.org> - 2017-03-15 15:30 +0100
    Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-15 16:50 +0100
      Re: [PATCH v2 0/5] mm: support parallel free of memory Michal Hocko <mhocko@kernel.org> - 2017-03-15 17:30 +0100
        Re: [PATCH v2 0/5] mm: support parallel free of memory Tim Chen <tim.c.chen@linux.intel.com> - 2017-03-15 22:40 +0100
          Re: [PATCH v2 0/5] mm: support parallel free of memory Michal Hocko <mhocko@kernel.org> - 2017-03-16 10:10 +0100
            Re: [PATCH v2 0/5] mm: support parallel free of memory Tim Chen <tim.c.chen@linux.intel.com> - 2017-03-16 19:40 +0100
              Re: [PATCH v2 0/5] mm: support parallel free of memory Minchan Kim <minchan@kernel.org> - 2017-03-17 09:10 +0100
              Re: [PATCH v2 0/5] mm: support parallel free of memory Michal Hocko <mhocko@kernel.org> - 2017-03-17 09:30 +0100
                Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-17 13:40 +0100
                Re: [PATCH v2 0/5] mm: support parallel free of memory Michal Hocko <mhocko@kernel.org> - 2017-03-17 14:00 +0100
                Re: [PATCH v2 0/5] mm: support parallel free of memory Peter Zijlstra <peterz@infradead.org> - 2017-03-17 14:20 +0100
                Re: [PATCH v2 0/5] mm: support parallel free of memory Peter Zijlstra <peterz@infradead.org> - 2017-03-17 14:00 +0100
                Re: [PATCH v2 0/5] mm: support parallel free of memory Michal Hocko <mhocko@kernel.org> - 2017-03-17 14:30 +0100
            Re: [PATCH v2 0/5] mm: support parallel free of memory Dave Hansen <dave.hansen@intel.com> - 2017-03-21 16:10 +0100
              Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-22 09:20 +0100
              Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-24 08:10 +0100
            Re: [PATCH v2 0/5] mm: support parallel free of memory Tim Chen <tim.c.chen@linux.intel.com> - 2017-03-21 16:20 +0100
        Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-16 08:00 +0100
        Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-16 08:40 +0100
          Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-16 15:00 +0100
            Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-16 15:20 +0100
  Re: [PATCH v2 0/5] mm: support parallel free of memory Vlastimil Babka <vbabka@suse.cz> - 2017-03-15 16:00 +0100
    Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-15 17:00 +0100
    Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-17 04:20 +0100
  Re: [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu <aaron.lu@intel.com> - 2017-03-17 03:30 +0100

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