[Webkit-unassigned] [Bug 45186] Use the Windows thread pool instead of an extra thread for FastMalloc scavenging

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=45186


Adam Roben (aroben) <aroben at apple.com> changed:

           What    |Removed                     |Added
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  Attachment #78538|review?, commit-queue?      |review-
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--- Comment #8 from Adam Roben (aroben) <aroben at apple.com>  2011-01-14 10:51:40 PST ---
(From update of attachment 78538)
View in context: https://bugs.webkit.org/attachment.cgi?id=78538&action=review

It's really too bad we can't reuse a previously-paused timer queue timer!

> Source/JavaScriptCore/wtf/FastMalloc.cpp:1536
> +ALWAYS_INLINE void TCMalloc_PageHeap::signalScavenger()
> +{
> +    ASSERT(IsHeld(pageheap_lock));
> +    if (!m_scavengingScheduled && shouldScavenge()) {
> +        m_scavengingScheduled = true;
> +        dispatch_resume(m_scavengeTimer);
> +    }
> +}
> +
> +#elif OS(WINDOWS)
> +
> +static void CALLBACK scavengerTimerFired(void* context, BOOLEAN)
> +{
> +    static_cast<TCMalloc_PageHeap*>(context)->periodicScavenge();
> +}
> +
> +void TCMalloc_PageHeap::initializeScavenger()
> +{
> +    m_scavengeQueueTimer = 0;
> +}
> +
> +ALWAYS_INLINE void TCMalloc_PageHeap::signalScavenger()
> +{
> +    ASSERT(IsHeld(pageheap_lock));
> +    if (!m_scavengeQueueTimer && shouldScavenge()) {
> +        DWORD period = kScavengeDelayInSeconds * 1000;
> +        CreateTimerQueueTimer(&m_scavengeQueueTimer, 0, scavengerTimerFired, 0, period, period, WT_EXECUTEDEFAULT);
> +    }
> +}

It would be nice if we could share a little more of the logic in signalScavenger(). Adding some new functions like isScavengerScheduled() (or its opposite, isScavengerSuspended()) and scheduleScavenger() should make that pretty easy.

> Source/JavaScriptCore/wtf/FastMalloc.cpp:2421
> +#if HAVE(DISPATCH_H)
> +        m_scavengingScheduled = false;
> +        dispatch_suspend(m_scavengeTimer);
> +#elif OS(WINDOWS)
> +        HANDLE scavengeQueueTimer = m_scavengeQueueTimer;
> +        m_scavengeQueueTimer = 0;
> +        DeleteTimerQueueTimer(0, scavengeQueueTimer, 0);
>  #endif

Maybe a suspendScavenger() function would make this cleaner.

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