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            <b><a class="bz_bug_link 
          bz_status_REOPENED "
   title="REOPENED - NetworkProcess: DNS prefetch happens in the Web Process"
   href="https://bugs.webkit.org/show_bug.cgi?id=147824#c15">Comment # 15</a>
              on <a class="bz_bug_link 
          bz_status_REOPENED "
   title="REOPENED - NetworkProcess: DNS prefetch happens in the Web Process"
   href="https://bugs.webkit.org/show_bug.cgi?id=147824">bug 147824</a>
              from <span class="vcard"><a class="email" href="mailto:ap&#64;webkit.org" title="Alexey Proskuryakov &lt;ap&#64;webkit.org&gt;"> <span class="fn">Alexey Proskuryakov</span></a>
</span></b>
        <pre>Comment on <span class=""><a href="attachment.cgi?id=262440&amp;action=diff" name="attach_262440" title="Updated patch">attachment 262440</a> <a href="attachment.cgi?id=262440&amp;action=edit" title="Updated patch">[details]</a></span>
Updated patch

View in context: <a href="https://bugs.webkit.org/attachment.cgi?id=262440&amp;action=review">https://bugs.webkit.org/attachment.cgi?id=262440&amp;action=review</a>

<span class="quote">&gt; Source/WebKit2/NetworkProcess/NetworkProcess.h:197
&gt; +    HashSet&lt;String&gt; m_dnsPrefetchedHosts;</span >

This HashSet grows indefinitely, and NetworkProcess can exist for weeks or even for months.

<span class="quote">&gt; Source/WebKit2/WebProcess/WebProcess.h:368
&gt; +    HashSet&lt;String&gt; m_dnsPrefetchedHosts;</span >

Is it OK to keep hosts here for a long time? I think that this may entirely disable the optimization of prefetching link hosts on hover - the hosts were already prefetched when loading, but the OS resolver may have well invalidated the cache already.

DNS prefetching is a really weird thing. We don't have any way to measure its effectiveness, which is not how we usually go about performance optimizations.</pre>
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