Messages in this thread | | | Date | Thu, 16 Apr 2020 13:37:36 -0700 | From | Minchan Kim <> | Subject | Re: [PATCH 10/28] mm: only allow page table mappings for built-in zsmalloc |
| |
Hi Christoph,
Sorry for the late.
On Sat, Apr 11, 2020 at 09:20:52AM +0200, Christoph Hellwig wrote: > Hi Minchan, > > On Fri, Apr 10, 2020 at 04:11:36PM -0700, Minchan Kim wrote: > > It doesn't mean we couldn't use zsmalloc as module any longer. It means > > we couldn't use zsmalloc as module with pgtable mapping whcih was little > > bit faster on microbenchmark in some architecutre(However, I usually temped > > to remove it since it had several problems). However, we could still use > > zsmalloc as module as copy way instead of pgtable mapping. Thus, if someone > > really want to rollback the feature, they should provide reasonable reason > > why it doesn't work for them. "A little fast" wouldn't be enough to exports > > deep internal to the module. > > do you have any data how much faster it is on arm (and does that include > arm64 as well)? Besides the exports which were my prime concern,
https://github.com/sjenning/zsmapbench
I need to recall the memory. IIRC, it was almost 30% faster at that time in ARM so was not trivial at that time. However, it was story from several years ago.
> zsmalloc with pgtable mappings also is the only user of map_kernel_range > outside of vmalloc.c, if it really is another code base for tiny > improvements we could mark map_kernel_range or in fact remove it entirely > and open code it in the remaining callers.
I alsh have temped to remove it. Let me have time to revist it in this chance.
Thanks.
| |