Public bug reported: I guess the reason is that Firefox doesn't delete huge cached video files from already closed pages/history and Linux is still keeping them in cached-disk RAM which leads to quick plummeting into swap and overwhelmingly reduced performance.
Steps to reproduce: View several [long] videos on Vimeo/Youtube in a row. System starts going into swap after several videos which is really uncomfortable on a 5400-rpm HDD. Restart Firefox. The video that was playing before the restart will easily be played and everything is okay unless you decide to watch more videos in a row. vm.swappiness = 25 ProblemType: Bug DistroRelease: Ubuntu 15.04 Package: firefox 40.0+build4-0ubuntu0.15.04.4 ProcVersionSignature: Ubuntu 3.19.0-26.28-generic 3.19.8-ckt4 Uname: Linux 3.19.0-26-generic x86_64 AddonCompatCheckDisabled: False ApportVersion: 2.17.2-0ubuntu1.3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: int 1583 F.... pulseaudio BuildID: 20150819100530 Channel: Unavailable CurrentDesktop: KDE Date: Thu Aug 27 04:20:26 2015 Extensions: extensions.sqlite corrupt or missing ForcedLayersAccel: False IfupdownConfig: # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback #auto eth0 #iface eth0 inet dhcp IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite) IpRoute: default via 192.168.0.1 dev ra0 proto static metric 1024 169.254.0.0/16 dev ra0 scope link metric 1000 192.168.0.0/24 dev ra0 proto kernel scope link src 192.168.0.3 Locales: extensions.sqlite corrupt or missing Plugins: IcedTea-Web Plugin (using IcedTea-Web 1.5.2 (1.5.2-1ubuntu2)) - /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so (icedtea-7-plugin) Google Talk Plugin Video Renderer - /opt/google/talkplugin/libnpo1d.so (google-talkplugin) Google Talk Plugin - /opt/google/talkplugin/libnpgoogletalk.so (google-talkplugin) Shockwave Flash - /usr/lib/adobe-flashplugin/libflashplayer.so (adobe-flashplugin) PrefSources: prefs.js [Profile]/extensions/kwallet@guillermo.molina/defaults/preferences/prefs.js Profiles: Profile0 (Default) - LastVersion=40.0/20150819100530 (In use) RelatedPackageVersions: icedtea-7-plugin 1.5.2-1ubuntu2 google-talkplugin 5.41.0.0-1 adobe-flashplugin 1:20150811.1-0vivid1 RunningIncompatibleAddons: False SourcePackage: firefox Themes: extensions.sqlite corrupt or missing UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 06/09/2013 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: X502CA.209 dmi.board.asset.tag: ATN12345678901234567 dmi.board.name: X502CA dmi.board.vendor: ASUSTeK COMPUTER INC. dmi.board.version: 1.0 dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: ASUSTeK COMPUTER INC. dmi.chassis.version: 1.0 dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrX502CA.209:bd06/09/2013:svnASUSTeKCOMPUTERINC.:pnX502CA:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnX502CA:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0: dmi.product.name: X502CA dmi.product.version: 1.0 dmi.sys.vendor: ASUSTeK COMPUTER INC. ** Affects: firefox (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug vivid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1489220 Title: Dramatic increase in RAM usage when viewing several videos in a row To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1489220/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs