Bug 48619

Summary:	[Qt][WK2] SharedMemory uses two pages for one page request
Product:	WebKit	Reporter:	Balazs Kelemen <kbalazs>
Component:	Platform	Assignee:	Nobody <webkit-unassigned>
Status:	RESOLVED DUPLICATE
Severity:	Normal	CC:	abecsi
Priority:	P2
Version:	528+ (Nightly build)
Hardware:	PC
OS:	All

Description Balazs Kelemen 2010-10-29 01:39:34 PDT

Our shared memory implementation tries to minimize the number of allocations trough recycling unused
mappings. This technique needs an extra word (word instead of a byte for aligning) in each mapping that
tracks that the memory is used or it has been released. The problem is that we ending up in allocating
an extra page if the client rounds up it's request to page size. This is the case of the VisitedLinkTable.

Comment 1 Balazs Kelemen 2010-10-29 01:50:30 PDT

Oh.... My patch asserts. The essence of that was to hack around
SharedMemory::systemPageSize to get back getpagesize() - extra_space
but there is an assert at VisitedLinkTable.cpp:60 - ASSERT(isPowerOf2(m_tableSize)); and this fails with the patch.
Grrrrrrr!

Comment 2 Balazs Kelemen 2010-11-02 02:06:55 PDT


*** This bug has been marked as a duplicate of bug 48520 ***