On Thu, 2003-02-20 at 08:10, David Smith wrote: > Thanks for the tips guys. I will be more trusting of my kernel from now > on. I imagine Linus knows better than I about what's a good use of my > swap. ;)
Well, actually, more than any other subsystem, the VM has been hotly debated over the 2.4 series. It has also been the source of many problems. (Remember the 2.4.9-2.4.10 jump -- they completely changed the VM. It upset a lot of people.) So we hope that Linus and crew know what's best... :) Michael > > --Dave > > <quote who="Michael Torrie"> > > On Wed, 2003-02-19 at 20:59, David Smith wrote: > >> Top says this about my memory usage: > >> > >> Mem: 257144K total, 225800K used, 31344K free, 21744K > >> buffers Swap: 1068312K total, 17936K used, 1050376K free, > >> 163552K cached > >> > >> Which means that I have about 194Mb free (31Mb free + 163Mb cached) > >> memory. Three questions: > >> > > Soren is correct. Linux aggressively uses swap to increase performance. > > > >> 1. Why is there some swap being used (17Mb)? > > > > The VM has determined that the working processes in memory only have a > > working set of x number of pages, so it swaps the rest out, and uses the > > ram for more important things like disk caching. I see that your > > question is why is there 31 Mb free and still using 17 mb of swap. > > Basically, Linux is being conservative. There's no reason for the 17 mb > > to be in memory, since they are outside the working set, so linux sets > > aside the space for future caching, or perhaps to maintain a certain > > number of free frames. > > > >> 2. How can I tell the kernel to free that up so that it's not using > >> any swap? > > > > Turn off the swap altogether. But I don't recommend. I've heard > > several people say things like "I have plenty of ram -- I don't need any > > swap." This may be true but I think swap is always a good idea. 1:1 > > these days is usually sufficient if you have at least 512 mb of ram. If > > you're planning on any image manipulation, perhaps 1 GB of swap would be > > good. > > > >> 3. Does it really matter? > > > > Not at all. > > > > Michael > > > > > >> > >> --Dave > >> > >> > >> > >> > >> ____________________ > >> BYU Unix Users Group > >> http://uug.byu.edu/ > >> ___________________________________________________________________ > >> List Info: http://phantom.byu.edu/cgi-bin/mailman/listinfo/uug-list > > -- > > Michael Torrie <[EMAIL PROTECTED]> > > > > > > ____________________ > > BYU Unix Users Group > > http://uug.byu.edu/ > > ___________________________________________________________________ List > > Info: http://phantom.byu.edu/cgi-bin/mailman/listinfo/uug-list > > > > > ____________________ > BYU Unix Users Group > http://uug.byu.edu/ > ___________________________________________________________________ > List Info: http://phantom.byu.edu/cgi-bin/mailman/listinfo/uug-list -- Michael L Torrie <[EMAIL PROTECTED]> ____________________ BYU Unix Users Group http://uug.byu.edu/ ___________________________________________________________________ List Info: http://phantom.byu.edu/cgi-bin/mailman/listinfo/uug-list
