Re: [PATCH 00/23] per device dirty throttling -v8
From: Arjan van de Ven <hidden>
Date: 2007-08-05 18:10:40
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In addition, big server boxes are usually not reading a huge *number* of files per second. The place where you see this as a problem is (a) compilation, thanks to huge /usr/include hierarchies (and here things have gotten worse over time as include files have gotten much more complex than in the early Unix days), and (b) silly desktop apps that want to scan huge numbers of XML files or who want to read every single image file on the desktop or in an open file browser window to show c00l icons. Oh, and I guess I should include Maildir setups. If you are always reading from the same small set of files (i.e., a database workload), then those inodes only get updated every 5 seconds (the traditional/default metadata update sync time, as well as the default ext3 journal update time), it's no big deal. Or if you are running a mail server, most of the time the mail queue files are getting updated anyway as you process them, and usually the mail is delivered before 5 seconds is up anyway.
it's just one of those things that get compounded with journaling filesystems though..... a single async write that happens "sometime in the future" is one thing... having a full transaction (which acts as barrier and synchronisation point) is something totally worse. -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>