Messages in this thread |  | | Date | Thu, 4 Jan 2001 14:34:48 -0200 (BRDT) | From | Rik van Riel <> | Subject | Re: try_to_swap_out() return value problem? |
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On Thu, 4 Jan 2001, Linus Torvalds wrote: > On Thu, 4 Jan 2001, Rik van Riel wrote: > > On Wed, 3 Jan 2001, Linus Torvalds wrote: > > > On Thu, 4 Jan 2001, Marcelo Tosatti wrote: > > > > > I agree that the return value of swap_out() is fairly meaningless. It's > > > been fairly meaningless for a long time now, and it's entirely possible > > > that the "while (swap_out())" loop should be just something like > > > > > > /* Scan the VM space, try to clean up the page tables a bit */ > > > for (i = 0 ; i <= nr_threads >> priority; i++) > > > swap_out(gfp_mask); > > > > The problem with this is that it means that page aging of > > the mapped active pages is no longer balanced against the > > aging of the unmapped active pages. > > Is there any reason to not just remove the lines > > if (!onlist) > /* The page is still mapped, so it can't be freeable... */ > age_page_down_ageonly(page); > > /* > * If the page is in active use by us, or if the page > * is in active use by others, don't unmap it or > * (worse) start unneeded IO. > */ > if (page->age > 0) > goto out_failed; > > from vmscan? > > They look like a complete hack, although an understandable one > from the time when the virtual memory scan used to actually do > IO as well. > > These days, if you think of the VM scanning as just a "shrink > the page tables" operation, the down-aging doesn't make much > sense. That will happen once the page has been moved to the > lists, no?
Hmmmm, I'm not sure ...
I can't quite put my finger on it, but my gut feeling says that removing this lines could unbalance the page aging and/or cause other nasties.
Then again, in theory the current VM should already be unbalanced and we haven't felt any bad effects yet ;)
regards,
Rik -- Hollywood goes for world dumbination, Trailer at 11.
http://www.surriel.com/ http://www.conectiva.com/ http://distro.conectiva.com.br/
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