On Tue, Feb 05, 2013 at 09:08:54AM +0900, Minchan Kim wrote: > Hi Greg, > > On Mon, Feb 04, 2013 at 10:51:46AM -0800, Greg Kroah-Hartman wrote: > > On Mon, Feb 04, 2013 at 09:23:41AM +0900, Minchan Kim wrote: > > > Zsmalloc has two methods 1) copy-based and 2) pte based to access > > > allocations that span two pages. > > > You can see history why we supported two approach from [1]. > > > > > > But it was bad choice that adding hard coding to select architecture > > > which want to use pte based method. This patch removed it and adds > > > new Kconfig to select the approach. > > > > > > This patch is based on next-20130202. > > > > > > [1] https://lkml.org/lkml/2012/7/11/58 > > > > > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > > Cc: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx> > > > Cc: Nitin Gupta <ngupta@xxxxxxxxxx> > > > Cc: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> > > > Cc: Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx> > > > Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> > > > --- > > > drivers/staging/zsmalloc/Kconfig | 12 ++++++++++++ > > > drivers/staging/zsmalloc/zsmalloc-main.c | 11 ----------- > > > 2 files changed, 12 insertions(+), 11 deletions(-) > > > > > > diff --git a/drivers/staging/zsmalloc/Kconfig b/drivers/staging/zsmalloc/Kconfig > > > index 9084565..2359123 100644 > > > --- a/drivers/staging/zsmalloc/Kconfig > > > +++ b/drivers/staging/zsmalloc/Kconfig > > > @@ -8,3 +8,15 @@ config ZSMALLOC > > > non-standard allocator interface where a handle, not a pointer, is > > > returned by an alloc(). This handle must be mapped in order to > > > access the allocated space. > > > + > > > +config ZSMALLOC_PGTABLE_MAPPING > > > + bool "Use page table mapping to access allocations that span two pages" > > > + depends on ZSMALLOC > > > + default n > > > + help > > > + By default, zsmalloc uses a copy-based object mapping method to access > > > + allocations that span two pages. However, if a particular architecture > > > + performs VM mapping faster than copying, then you should select this. > > > + This causes zsmalloc to use page table mapping rather than copying > > > + for object mapping. You can check speed with zsmalloc benchmark[1]. > > > + [1] https://github.com/spartacus06/zsmalloc > > > diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c > > > index 06f73a9..b161ca1 100644 > > > --- a/drivers/staging/zsmalloc/zsmalloc-main.c > > > +++ b/drivers/staging/zsmalloc/zsmalloc-main.c > > > @@ -218,17 +218,6 @@ struct zs_pool { > > > #define CLASS_IDX_MASK ((1 << CLASS_IDX_BITS) - 1) > > > #define FULLNESS_MASK ((1 << FULLNESS_BITS) - 1) > > > > > > -/* > > > - * By default, zsmalloc uses a copy-based object mapping method to access > > > - * allocations that span two pages. However, if a particular architecture > > > - * performs VM mapping faster than copying, then it should be added here > > > - * so that USE_PGTABLE_MAPPING is defined. This causes zsmalloc to use > > > - * page table mapping rather than copying for object mapping. > > > -*/ > > > -#if defined(CONFIG_ARM) > > > -#define USE_PGTABLE_MAPPING > > > -#endif > > > > Did you test this? I don't see the new config value you added actually > > do anything in this code. Also, if I select it incorrectly on ARM, or > > *slaps self* Ok, so I'll drop this patch now. As for what to do instead, I have no idea, sorry, but the others should. thanks, greg k-h -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>