* KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2010-12-01 14:35:50]: > On Wed, 1 Dec 2010 10:52:59 +0530 > Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote: > > > * Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> [2010-12-01 10:48:16]: > > > > > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2010-12-01 10:32:54]: > > > > > > > On Tue, 30 Nov 2010 15:46:31 +0530 > > > > Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > Provide control using zone_reclaim() and a boot parameter. The > > > > > code reuses functionality from zone_reclaim() to isolate unmapped > > > > > pages and reclaim them as a priority, ahead of other mapped pages. > > > > > > > > > > Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> > > > > > --- > > > > > include/linux/swap.h | 5 ++- > > > > > mm/page_alloc.c | 7 +++-- > > > > > mm/vmscan.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++- > > > > > 3 files changed, 79 insertions(+), 5 deletions(-) > > > > > > > > > > diff --git a/include/linux/swap.h b/include/linux/swap.h > > > > > index eba53e7..78b0830 100644 > > > > > --- a/include/linux/swap.h > > > > > +++ b/include/linux/swap.h > > > > > @@ -252,11 +252,12 @@ extern int vm_swappiness; > > > > > extern int remove_mapping(struct address_space *mapping, struct page *page); > > > > > extern long vm_total_pages; > > > > > > > > > > -#ifdef CONFIG_NUMA > > > > > -extern int zone_reclaim_mode; > > > > > extern int sysctl_min_unmapped_ratio; > > > > > extern int sysctl_min_slab_ratio; > > > > > extern int zone_reclaim(struct zone *, gfp_t, unsigned int); > > > > > +extern bool should_balance_unmapped_pages(struct zone *zone); > > > > > +#ifdef CONFIG_NUMA > > > > > +extern int zone_reclaim_mode; > > > > > #else > > > > > #define zone_reclaim_mode 0 > > > > > static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order) > > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > > > > index 62b7280..4228da3 100644 > > > > > --- a/mm/page_alloc.c > > > > > +++ b/mm/page_alloc.c > > > > > @@ -1662,6 +1662,9 @@ zonelist_scan: > > > > > unsigned long mark; > > > > > int ret; > > > > > > > > > > + if (should_balance_unmapped_pages(zone)) > > > > > + wakeup_kswapd(zone, order); > > > > > + > > > > > > > > Hm, I'm not sure the final vision of this feature. Does this reclaiming feature > > > > can't be called directly via balloon driver just before alloc_page() ? > > > > > > > > > > That is a separate patch, this is a boot paramter based control > > > approach. > > > > > > > Do you need to keep page caches small even when there are free memory on host ? > > > > > > > > > > The goal is to avoid duplication, as you know page cache fills itself > > > to consume as much memory as possible. The host generally does not > > > have a lot of free memory in a consolidated environment. > > > > > That's a point. Then, why the guest has to do _extra_ work for host even when > the host says nothing ? I think trigger this by guests themselves is not very good. I've mentioned it before, the guest keeping free memory without a large performance hit, helps, the balloon driver is able to quickly retrieve this memory if required or the guest can use this memory for some other application/task. The cached data is mostly already present in the host page cache. -- Three Cheers, Balbir -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
