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From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Will Deacon <will@kernel.org>, Kees Cook <keescook@chromium.org>,
	Ingo Molnar <mingo@kernel.org>,
	Elena Reshetova <elena.reshetova@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Hanjun Guo <guohanjun@huawei.com>,
	Jan Glauber <jglauber@marvell.com>
Subject: [PATCH v2 0/6] Rework REFCOUNT_FULL using atomic_fetch_* operations
Date: Tue, 27 Aug 2019 17:31:58 +0100	[thread overview]
Message-ID: <20190827163204.29903-1-will@kernel.org> (raw)

Hi all,

This is version two of the patches I previously posted here:

  https://lkml.kernel.org/r/20190802101000.12958-1-will@kernel.org

Changes since v1 include:

  * Avoid duplicate WARNs when incrementing from zero
  * Some crude lktdm perf results to motivate the change:

    # perf stat -r 3 -B -- echo {ATOMIC,REFCOUNT}_TIMING >/sys/kernel/debug/provoke-crash/DIRECT

    # arm64
    ATOMIC_TIMING:					46.50451 +- 0.00134 seconds time elapsed  ( +-  0.00% )
    REFCOUNT_TIMING (REFCOUNT_FULL, mainline):		77.57522 +- 0.00982 seconds time elapsed  ( +-  0.01% )
    REFCOUNT_TIMING (REFCOUNT_FULL, this series):	48.7181 +- 0.0256 seconds time elapsed  ( +-  0.05% )

    # x86
    ATOMIC_TIMING:					31.6225 +- 0.0776 seconds time elapsed  ( +-  0.25% )
    REFCOUNT_TIMING (!REFCOUNT_FULL, mainline/x86 asm): 31.6689 +- 0.0901 seconds time elapsed  ( +-  0.28% )
    REFCOUNT_TIMING (REFCOUNT_FULL, mainline):		53.203 +- 0.138 seconds time elapsed  ( +-  0.26% )
    REFCOUNT_TIMING (REFCOUNT_FULL, this series):	31.7408 +- 0.0486 seconds time elapsed  ( +-  0.15% )

Cheers,

Will

Cc: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Jan Glauber <jglauber@marvell.com>

--->8

Will Deacon (6):
  lib/refcount: Define constants for saturation and max refcount values
  lib/refcount: Ensure integer operands are treated as signed
  lib/refcount: Remove unused refcount_*_checked() variants
  lib/refcount: Move bulk of REFCOUNT_FULL implementation into header
  lib/refcount: Improve performance of generic REFCOUNT_FULL code
  lib/refcount: Consolidate REFCOUNT_{MAX,SATURATED} definitions

 drivers/misc/lkdtm/refcount.c |   8 --
 include/linux/refcount.h      | 236 +++++++++++++++++++++++++++++++++++++----
 lib/refcount.c                | 237 +-----------------------------------------
 3 files changed, 218 insertions(+), 263 deletions(-)

-- 
2.11.0


             reply	other threads:[~2019-08-27 16:32 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-27 16:31 Will Deacon [this message]
2019-08-27 16:31 ` [PATCH v2 1/6] lib/refcount: Define constants for saturation and max refcount values Will Deacon
2019-08-27 16:32 ` [PATCH v2 2/6] lib/refcount: Ensure integer operands are treated as signed Will Deacon
2019-08-27 16:32 ` [PATCH v2 3/6] lib/refcount: Remove unused refcount_*_checked() variants Will Deacon
2019-08-27 16:32 ` [PATCH v2 4/6] lib/refcount: Move bulk of REFCOUNT_FULL implementation into header Will Deacon
2019-08-27 16:32 ` [PATCH v2 5/6] lib/refcount: Improve performance of generic REFCOUNT_FULL code Will Deacon
2019-08-27 16:32 ` [PATCH v2 6/6] lib/refcount: Consolidate REFCOUNT_{MAX,SATURATED} definitions Will Deacon
2019-08-27 17:51 ` [PATCH v2 0/6] Rework REFCOUNT_FULL using atomic_fetch_* operations Kees Cook
2019-08-28  7:30 ` Peter Zijlstra
2019-08-28 14:14   ` Will Deacon
2019-08-28 21:03     ` Kees Cook
2019-08-31 17:48       ` Ard Biesheuvel
2019-08-31 19:02         ` Kees Cook
2019-08-31 20:54           ` Ard Biesheuvel
2019-09-06 13:43       ` Will Deacon
2019-09-07  1:57         ` Hanjun Guo

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