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List:       kde-bugs-dist
Subject:    [Bug 160284] bad mmap causes cores in KPCMemoryDevice
From:       Rivo Laks <rivolaks () hot ! ee>
Date:       2008-05-30 13:30:57
Message-ID: 20080530133057.3084.qmail () ktown ! kde ! org
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http://bugs.kde.org/show_bug.cgi?id=160284         




------- Additional Comments From rivolaks hot ee  2008-05-30 15:30 -------
With mmap disabled, you'll probably get extra file open+close operation whenever the \
cache is accessed. But it shouldn't be that slow, I remember using the cache was \
faster than not using cache even before I implemented the mmap support. So I think \
you can disable it safely until the problem gets sorted out.

deleteCache() might indeed be causing problems, it should probably do something like \
KPixmapCachePrivate::invalidateMmapFiles() to make all KPixmapCache objects re-mmap \
the files. The problem is that deleteCache() is static and therefore doesn't have the \
mmapped memory. Maybe it could temporarily mmap it, just to invalidate it?

It might also be worth it to check in KPixmapCache::Private::dataDevice() if the data \
file exists before opening KPCMemoryDevice on it (as the latter accesses the mmapped \
memory which could be invalid if the file has been deleted). Private::indexDevice \
already does that.


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