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Issue 897742 link

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Issue metadata

Status: Fixed
Owner:
Closed: Oct 22
Cc:
EstimatedDays: ----
NextAction: ----
OS: Linux , Android
Pri: 3
Type: Bug

Blocking:
issue 94925



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Check if spinlock_linux-inl.h could use futex unconditionally

Project Member Reported by thakis@chromium.org, Oct 22

Issue description

https://cs.chromium.org/chromium/src/third_party/tcmalloc/chromium/src/base/spinlock_linux-inl.h?q=futex_private_flag+&dr=CSs&l=43 currently has a static initializer to check if syscall(__NR_futex) works. That syscall has been around since linux 2.6.0 (2003) and the absl version doesn't have this check from what I can tell (https://cs.chromium.org/chromium/src/third_party/abseil-cpp/absl/synchronization/internal/waiter.cc?type=cs&q=futex_private_flag+&g=0&l=63)

We also use futex_private_flag which was added in 2.6.22 (jul 2007). absl uses that unconditionally as well.

I'm guessing we can just remove that check and assume it succeeds. +linux folks to confirm/deny :-)
 
Cc: -thestig@google.com thestig@chromium.org
Project Member

Comment 3 by bugdroid1@chromium.org, Oct 22

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/211f614f196da95723f115921c631d274a064657

commit 211f614f196da95723f115921c631d274a064657
Author: Nico Weber <thakis@chromium.org>
Date: Mon Oct 22 16:21:01 2018

linux: Lower static initializer expectations by 1, to 5.

https://chromium-review.googlesource.com/c/1293559 removed another SI.

TBR=dpranke

Bug:  897742 ,94925
Change-Id: I24dccd770fcba4f06bd85c6da7678adc95b40601
Reviewed-on: https://chromium-review.googlesource.com/c/1293795
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601606}
[modify] https://crrev.com/211f614f196da95723f115921c631d274a064657/infra/scripts/legacy/scripts/slave/chromium/sizes.py

Owner: thakis@chromium.org
Status: Fixed (was: Untriaged)

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