Guarantee that newly created shared memory is zeroed
Categories
(Core :: IPC, enhancement)
Tracking
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Tracking | Status | |
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firefox80 | --- | fixed |
People
(Reporter: jld, Assigned: jld)
Details
Attachments
(1 file)
There was a question recently in Matrix about whether IPC shared memory is zeroed when it's created. Newly created shared memory is acquired from the OS, so for security reasons the OS won't give us a previous allocation's data like for malloc
; in practice that means it's zeroed (rather than filled with some nonzero pattern), and this is observed to be the case with the APIs we currently use, but we should guarantee that to save callers the cost of unnecessary memset
s. I've written some unit tests to check this.
Assignee | ||
Comment 1•4 years ago
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Pushed by jedavis@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/97d02fb626d4 Verify that newly allocated shared memory is zeroed. r=mccr8
Comment 3•4 years ago
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bugherder |
Comment 4•4 years ago
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== Change summary for alert #26520 (as of Thu, 16 Jul 2020 06:24:24 GMT) ==
Improvements:
59% build times windows2012-32-shippable opt instrumented taskcluster-c5.4xlarge 1,579.95 -> 642.93
51% build times windows2012-32-shippable opt instrumented taskcluster-c5d.4xlarge 1,513.29 -> 734.57
For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=26520
Assignee | ||
Comment 5•4 years ago
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This was a simple patch to add some tests; it almost certainly didn't improve build time.
Description
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