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Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic

From Christoph Lameter <cl@linux.com>
Newsgroups linux.kernel
Subject Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic
Date 2016-03-08 16:10 +0100
Message-ID <rarqO-2vx-23@gated-at.bofh.it> (permalink)
References <raqXM-25J-23@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Tue, 8 Mar 2016, Vineet Gupta wrote:

> This in turn happened because slab_unlock() doesn't serialize properly
> (doesn't use atomic clear) with a concurrent running
> slab_lock()->test_and_set_bit()

This is intentional because of the increased latency of atomic
instructions. Why would the unlock need to be atomic? This patch will
cause regressions.

Guess this is an architecture specific issue of modified
cachelines not becoming visible to other processors?

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Thread

[PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-03-08 15:40 +0100
  Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Christoph Lameter <cl@linux.com> - 2016-03-08 16:10 +0100
    Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <vgupta@synopsys.com> - 2016-03-08 16:50 +0100
      Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Christoph Lameter <cl@linux.com> - 2016-03-08 21:50 +0100
        Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-03-09 07:50 +0100
          Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Peter Zijlstra <peterz@infradead.org> - 2016-03-09 11:20 +0100
            Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Peter Zijlstra <peterz@infradead.org> - 2016-03-09 11:40 +0100
              Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-03-09 12:20 +0100
            Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-03-09 12:10 +0100
              Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Peter Zijlstra <peterz@infradead.org> - 2016-03-09 12:50 +0100
                Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-03-09 13:00 +0100
                Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Peter Zijlstra <peterz@infradead.org> - 2016-03-09 13:30 +0100
                Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-03-14 09:10 +0100
            Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-03-09 14:30 +0100
              Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Peter Zijlstra <peterz@infradead.org> - 2016-03-09 16:00 +0100
                Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-03-10 07:00 +0100
                Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Peter Zijlstra <peterz@infradead.org> - 2016-03-10 10:20 +0100
  Re: [PATCH] mm: slub: Ensure that slab_unlock() is atomic Vlastimil Babka <vbabka@suse.cz> - 2016-03-08 16:40 +0100

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