https://bugs.kde.org/show_bug.cgi?id=388854
--- Comment #30 from Tobias Deiminger <haxti...@posteo.de> --- (In reply to Albert Astals Cid from comment #28) > *BUT* this may actually be a manifestation of "glibc is useless and doesn't > actually free memory when you tell it to" that i workarounded at > https://cgit.kde.org/okular.git/commit/ > ?id=95bc29a76fc1f93eaabe5383d934644067dfc884 That's well possible. I did some memory forensics with attachment 109856 loaded. The observations could be explained by glibc not freeing memory. Important note in advance: Yes, Okular caches pages. But it stores them as QPixmaps (e.g., see PagePrivate::m_pixmaps). This means, at least on X11, the image payload is not kept in Okulars heap. QPixmap objects are just wrappers around X11 pixmap handles [0]. The raw image data is stored in memory managed by the X11 server, not in Okulars heap. Following this theory, I shouldn't be able to find bitmaps in heap. I iterated over all malloc chunks in a gdb session (using gdb gef with some customization), and checked for suspicious chunks (by vtable, by size). There were several chunks of size > 4 MiB, flagged as "in use". Such big chunks could be bitmaps, just guessing by their sheer size. I dumped the memory range of such a chunk into a file, like: (gdb) dump binary memory /tmp/dump.bin 0x55a80d790560 0x55A80DB71BF0 When opening /tmp/dump.bin in Gimp as raw image, and playing around with width and height a bit, it looked like attachment 113727. Quite clear case. This is either the reminder of a page bitmap, or Maxwells Daemon did a quite good job :) What does this tell us? Imo it tells there's the inner bitmap of a QImage hanging around in the heap, a thing that shouldn't be. QImages are only used temporarily, when they're sent from the rendering thread over a queued connection to the main thread. After transforming them into QPixmap (in Generator::generatePixmap), they should be freed. If they are not, this could for example mean there are some QImages stuck in the queue, or it could be some glibc behavior as mentioned by Albert. Albert, Oliver: If you think I'm on the wrong track, please stop me from digging deeper. [0] ftp://www.x.org/pub/X11R7.7/doc/man/man3/xcb_create_pixmap.3.xhtml -- You are receiving this mail because: You are watching all bug changes.
