<html><head><meta content="text/html; charset=us-ascii" http-equiv="Content-Type"></head><body><div><div style="font-family: Calibri,sans-serif; font-size: 11pt;">What is special kernel memory?<br><br>What is a special type of memory leak?<br><br>Are you suggesting that the Linux kernel is particularly unstable?<br><br>Are you sure it's JavaScript that is the issue or could it be Java? If JavaScript, are you suggesting that Firefox is unstable?<br><br>---<br>Sent using a tiny phone keyboard.<br>Apologies for any typos and autocorrect.<br>Also, this old phone only supports top post. Apologies.<br><br>Cy Schubert<br><Cy.Schubert@cschubert.com> or <cy@freebsd.org><br>The need of the many outweighs the greed of the few.<br>---<br></div></div><hr><span style="font-family: Tahoma,sans-serif; font-size: 10pt; font-weight: bold;">From: </span><span style="font-family: Tahoma,sans-serif; font-size: 10pt;">Alan W. Irwin</span><br><span style="font-family: Tahoma,sans-serif; font-size: 10pt; font-weight: bold;">Sent: </span><span style="font-family: Tahoma,sans-serif; font-size: 10pt;">29/01/2018 14:18</span><br><span style="font-family: Tahoma,sans-serif; font-size: 10pt; font-weight: bold;">To: </span><span style="font-family: Tahoma,sans-serif; font-size: 10pt;">Cy Schubert</span><br><span style="font-family: Tahoma,sans-serif; font-size: 10pt; font-weight: bold;">Cc: </span><span style="font-family: Tahoma,sans-serif; font-size: 10pt;">discuss@vlug.org</span><br><span style="font-family: Tahoma,sans-serif; font-size: 10pt; font-weight: bold;">Subject: </span><span style="font-family: Tahoma,sans-serif; font-size: 10pt;">Re: [Discuss] I need a recommendation for a Linux-compatible high-endPC builder</span><br><br>On 2018-01-29 06:27-0800 Cy Schubert wrote:<br><br>> In message <alpine.DEB.2.11.1801282249140.18536@enira.zlyna.ubzr>,<br>> "Alan W. Irw<br>> in" writes:<br>>> On 2018-01-28 21:16-0800 Cy Schubert wrote:<br>>><br>>>> Memory leaks should be fixed. As an O/S developer I appreciate bug<br>>>> reports, especially detailed bug reports. It all helps.<br>>><br>>> Hi Cy:<br>>><br>>> I completely agree that memory leaks caused by the OS system should be<br>>> reported. And I also think such leaks generally are reported and are<br>>> fixed (at least on OS's based entirely on free software such as Linux<br>>> and *BSD) thanks to strong community support and appeals like yours.<br>>> However, that good free software feeling is not so clear for<br>>> javascript memory leaks created by a set of bad javascript commands<br>>> created by some anonymous company in webspace. I think such commands<br>>> do technically qualify as "open source" but not necessarily free<br>>> software. However, they are so obfuscated by the many layers of<br>>> javascript that hierarchically include them, that it makes such issues<br>>> difficult to fix which is another motivation for using a whitelist<br>>> approach such as the "noscript" extension for firefox for domains<br>>> which you trust to have good javascript.<br>><br>> Restart your browser then.<br><br>Agreed. Restarting the application that is leaking<br>is a workaround for most memory leaks, but that quickly<br>becomes a pain so ideally noscript helps you avoid javascript<br>related memory leaks for firefox that are generated by bad javascript<br>code out there "somewhere on the web".<br><br>> Why reboot the machine?<br><br>I agree rebooting is obviously not necessary with ordinary<br>memory leaks unless you cannot find which application is doing it or<br>the memory leak runs you out of memory so quickly that your system<br>dies (requiring a reboot) before you can diagnose the problem.<br><br>Another kind of memory leak which typically requires a reboot is leaks<br>of special memory allocated by the kernel within a certain area of<br>ordinary memory of fixed size (at least for the kernel of 3-years ago<br>where I encountered one of these types of special kernel memory<br>leaks). I have no idea whether modern Linux kernels or the *BSD<br>kernels ever this fixed memory size technique for allocating special<br>kinds of memory, and I have forgotten the details. But IIRC, these<br>special kernel memory types and their size are noted within the<br>/sys/kernel heirarchy of "files" that are available with Linux so you<br>have to look at those sizes and see how they grow with time compared<br>with a healthy Linux system to figure out which kind of special kernel<br>memory is leaking. But otherwise the only symptom of trouble for this<br>type of special memory leak was an overall obvious system slowdown<br>some days after booting, with nothing showing in top or free results<br>because of that area of ordinary memory of fixed size. So if anyone<br>here runs into this set of symptoms, they should consider the<br>possibility of a special memory leak.<br><br>Alan<br>__________________________<br>Alan W. Irwin<br><br>Astronomical research affiliation with Department of Physics and Astronomy,<br>University of Victoria (astrowww.phys.uvic.ca).<br><br>Programming affiliations with the FreeEOS equation-of-state<br>implementation for stellar interiors (freeeos.sf.net); the Time<br>Ephemerides project (timeephem.sf.net); PLplot scientific plotting<br>software package (plplot.sf.net); the libLASi project<br>(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);<br>and the Linux Brochure Project (lbproject.sf.net).<br>__________________________<br><br>Linux-powered Science<br>__________________________<br><br></body></html>