Messages in this thread | | | Date | Fri, 25 Sep 2015 17:47:13 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH v2] zbud: allow up to PAGE_SIZE allocations |
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On Fri, Sep 25, 2015 at 10:17:54AM +0200, Vitaly Wool wrote: > <snip> > > I already said questions, opinion and concerns but anything is not clear > > until now. Only clear thing I could hear is just "compaction stats are > > better" which is not enough for me. Sorry. > > > > 1) https://lkml.org/lkml/2015/9/15/33 > > 2) https://lkml.org/lkml/2015/9/21/2 > > Could you please stop perverting the facts, I did answer to that: > https://lkml.org/lkml/2015/9/21/753. > > Apart from that, an opinion is not necessarily something I would > answer. Concerns about zsmalloc are not in the scope of this patch's > discussion. If you have any concerns regarding this particular patch, > please let us know.
Yes, I don't want to interrupt zbud thing which is Seth should maintain and I respect his decision but the reason I nacked is you said this patch aims for supporing zbud into zsmalloc for determinism. For that, at least, you should discuss with me and Sergey but I feel you are ignoring our comments.
> > > Vitally, Please say what's the root cause of your problem and if it > > is external fragmentation, what's the problem of my approach? > > > > 1) make non-LRU page migrate > > 2) provide zsmalloc's migratpage > > The problem with your approach is that in your world I need to prove > my right to use zbud. This is a very strange speculation.
No. If you want to contribute something, you should prove why yours is better. I already said my concerns and my approach. It's your turn that you should explain why it's better.
> > > We should provide it for CMA as well as external fragmentation. > > I think we could solve your issue with above approach and > > it fundamentally makes zsmalloc/zbud happy in future. > > I doubt that but I'll answer in this thread: > https://lkml.org/lkml/2015/9/15/33 as zsmalloc deficiencies do not > have direct relation to this particular patch. > > > Also, please keep it in mind that zram has been in linux kernel for > > memory efficiency for a long time and later zswap/zbud was born > > for *determinism* at the cost of memory efficiency. > > Yep, and determinism is more important to me than the memory > efficiency. Dropping the compression ration from 3.2x to 1.8x is okay > with me and stalls in UI are not.
Then, you could use zswap which have aimed for it with small changes to prevent writeback.
> > ~vitaly
-- Kind regards, Minchan Kim
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