search for: bb01b64cfab7

This patch is a revert of 'commit bb01b64cfab7 ("mm/balloon_compaction.c: enqueue zero page to balloon device")' Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and shouldn't be given to the host ksmd to scan. Therefore, it is not necessary to zero ballooned pages, which is very time consuming when the page...

This patch is a revert of 'commit bb01b64cfab7 ("mm/balloon_compaction.c: enqueue zero page to balloon device")' Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and shouldn't be given to the host ksmd to scan. Therefore, it is not necessary to zero ballooned pages, which is very time consuming when the page...

Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and shouldn't be given to the host ksmd to scan. Therefore, it is not necessary to zero ballooned pages, which is very time consuming when the page amount is large. The ongoing fast balloon tests show that the time to balloon 7G pages is increased from ~491ms to 2.8 seconds with __GFP_ZERO added. So, this patch removes the flag.

Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and shouldn't be given to the host ksmd to scan. Therefore, it is not necessary to zero ballooned pages, which is very time consuming when the page amount is large. The ongoing fast balloon tests show that the time to balloon 7G pages is increased from ~491ms to 2.8 seconds with __GFP_ZERO added. So, this patch removes the flag.

...is very time consuming when >> the page amount is large. The ongoing fast balloon tests show that the >> time to balloon 7G pages is increased from ~491ms to 2.8 seconds with >> __GFP_ZERO added. So, this patch removes the flag. > Please make it obvious that this is a revert of bb01b64cfab7 > ("mm/balloon_compaction.c: enqueue zero page to balloon device"). > > Ok, will do. Best, Wei

...is very time consuming when >> the page amount is large. The ongoing fast balloon tests show that the >> time to balloon 7G pages is increased from ~491ms to 2.8 seconds with >> __GFP_ZERO added. So, this patch removes the flag. > Please make it obvious that this is a revert of bb01b64cfab7 > ("mm/balloon_compaction.c: enqueue zero page to balloon device"). > > Ok, will do. Best, Wei

...ed pages, which is very time consuming when > the page amount is large. The ongoing fast balloon tests show that the > time to balloon 7G pages is increased from ~491ms to 2.8 seconds with > __GFP_ZERO added. So, this patch removes the flag. Please make it obvious that this is a revert of bb01b64cfab7 ("mm/balloon_compaction.c: enqueue zero page to balloon device"). > Signed-off-by: Wei Wang <wei.w.wang at intel.com> > --- > mm/balloon_compaction.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/balloon_compaction.c b/mm/balloon_co...

...where this MADV_DONTNEED is done, please? > > Sure. It's done in the hypervisor when the balloon pages are received. > > Please see line 40 at > https://github.com/qemu/qemu/blob/master/hw/virtio/virtio-balloon.c Thanks. Are all hypervisors which are using this API doing this? bb01b64cfab7 doesn't mention the specify hypervisor nor does it mention any real numbers so I suspect the revert is the right thing to do but the changelog should mention all those details. -- Michal Hocko SUSE Labs

On Thu 03-08-17 19:59:17, Wei Wang wrote: > This patch is a revert of 'commit bb01b64cfab7 ("mm/balloon_compaction.c: > enqueue zero page to balloon device")' > > Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and > shouldn't be given to the host ksmd to scan. I find MADV_DONTNEED reference still quite confusing. What do you think about...

On 03.08.2017 13:59, Wei Wang wrote: > This patch is a revert of 'commit bb01b64cfab7 ("mm/balloon_compaction.c: > enqueue zero page to balloon device")' > > Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and > shouldn't be given to the host ksmd to scan. Therefore, it is not > necessary to zero ballooned pages, which is very time...

On Mon 07-08-17 10:44:50, David Hildenbrand wrote: > On 03.08.2017 13:59, Wei Wang wrote: > > This patch is a revert of 'commit bb01b64cfab7 ("mm/balloon_compaction.c: > > enqueue zero page to balloon device")' > > > > Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and > > shouldn't be given to the host ksmd to scan. Therefore, it is not > > necessary to zero ballooned...

On Mon 07-08-17 10:44:50, David Hildenbrand wrote: > On 03.08.2017 13:59, Wei Wang wrote: > > This patch is a revert of 'commit bb01b64cfab7 ("mm/balloon_compaction.c: > > enqueue zero page to balloon device")' > > > > Ballooned pages will be marked as MADV_DONTNEED by the hypervisor and > > shouldn't be given to the host ksmd to scan. Therefore, it is not > > necessary to zero ballooned...