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Topic: Swap problem in dsl-2.0, Inappropriate swapping?< Next Oldest | Next Newest >
WDef Offline





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Posted: Dec. 05 2005,06:49 QUOTE

For the moment I've shredded the swap partition.  But this is a workaround not a solution.

Thanks Mik - I know about the Friedgold hack increasing the size of the ramdisk to take in swapspace (not in dsl-1.5), but should a 36MB file write to /home/dsl be allowed to spill onto the swap "portion" of the ramdisk when there's 1GB of ram (still 497904 ram free).  Also data appears to be getting swapped out in huge amounts as a result of this file copy (*much* bigger than the 36MB file).    

ie shouldn't it ideally be such that the ram part of the ramdisk gets filled with a new file write before utilising swap-ramdisk.  File copies (incl extension loadings I imagine) appear to be using swap when there is no need.  Presumably also happening on systems with much less ram.
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mikshaw Offline





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Posted: Dec. 05 2005,15:20 QUOTE

From the way I understand it the ramdisk is created from a portition of ram + a portion of swap.  You get a fixed-sized ramdisk as a result, with the rest of your ram being left alone to be used as ram in the typical manner.  If /home is mounted in /ramdisk, you have a fixed amount of physical ram available for it...when that part of ram is filled it has to move to swap.  This may not be fact, but it's just the way it appears to me.

You can use the df command to see how much of /ramdisk is available.


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WDef Offline





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Posted: Dec. 10 2005,13:35 QUOTE

I think I'd prefer to see friedgold's hack enabled only by a boot option eg for low ram users.   Easy enough to do, just an "if checkbootparam..." etc around it in knoppix-autoconfig

Just my opinion.
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cbagger01 Offline





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Posted: Dec. 10 2005,21:14 QUOTE

friedgold's hack should be able to be turned into a boot option, or at the very least, it could be ON by default and then DISABLED via a boot option.

However, I am still curious to know why booting with an existing option like

dsl noswap

does not work?
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WDef Offline





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Posted: Dec. 15 2005,10:31 QUOTE

Perhaps one thing I didn't make clear is that, once swap gets filled during the large file copy, the copying process slows right down and so do subsequent file copies.  noswap stops this behaviour (didn't I say that? - no matter) - ramdisk obviously can't be remounted at a larger size including the size of swap if there's no swap.

But what of users with +++ram, who try dsl and find their existing swap being used, but don't know about noswap or the expanded ramdisk, and then find some file copying grinds to a near halt?

This caters for low ram users, who are a significant segment (but not all) of dsl users, and by all accounts this is very helpful indeed to them, so they need to be able to at very least switch it on.

The question I'm raising is: I'm not convinced this behavior should be on by default when, as time goes by, more users are bound to have adequate amounts of ram, and therefore not need this hack, which does seem to exact a performance penalty in the case I described?
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