Messages in this thread | | | Date | Thu, 4 Jun 2015 12:50:25 +0900 | From | Minchan Kim <> | Subject | Re: [RFC][PATCH 03/10] zsmalloc: introduce zs_can_compact() function |
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On Thu, Jun 04, 2015 at 12:42:30PM +0900, Sergey Senozhatsky wrote: > On (06/04/15 12:30), Minchan Kim wrote: > > > -- free objects in class: 5 (free-objs class capacity) > > > -- page1: inuse 2 > > > -- page2: inuse 2 > > > -- page3: inuse 3 > > > -- page4: inuse 2 > > > > What scenario do you have a cocern? > > Could you describe this example more clear? > > you mean "how is this even possible"?
No I meant. I couldn't understand your terms. Sorry.
What free-objs class capacity is? page1 is zspage?
Let's use consistent terms between us.
For example, maxobj-per-zspage is 4. A is allocated and used. X is allocated but not used. so we can draw a zspage below.
AAXX
So we can draw several zspages linked list as below
AAXX - AXXX - AAAX
Could you describe your problem again?
Sorry.
> > well, for example, > > make -jX > make clean > > can introduce a significant fragmentation. no new objects, just random > objs removal. assuming that we keep some of the objects, allocated during > compilation. > > e.g. > > ... > > page1 > allocate baz.so > allocate foo.o > page2 > allocate bar.o > allocate foo.so > ... > pageN > > > > now `make clean` > > page1: > allocated baz.so > empty > > page2 > empty > allocated foo.so > > ... > > pageN > > in the worst case, every page can turn out to be ALMOST_EMPTY. > > -ss
-- Kind regards, Minchan Kim
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