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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 2 of 2] xenpaging:change page-in process to speed up page-in in xenpaging
Hello,
At 03:50 +0000 on 05 Jan (1325735430), hongkaixing@xxxxxxxxxx wrote:
> xenpaging:change page-in process to speed up page-in in xenpaging
> In this patch,we change the page-in process.Firstly,we add a new function
> paging_in_trigger_sync
> to handle page-in requests directly.and when the requests' count is up to
> 32,then handle them
> batchly;Most importantly,we use an increasing gfn to test_bit,which saves
> much time.
> In p2m.c,we changes p2m_mem_paging_populate() to return a value;
> The following is a xenpaging test on suse11-64 with 4G memory.
>
> Nums of page_out pages Page out time Page in time(in unstable code)
> Page in time(apply this patch)
> 512M(131072) 2.6s 540s
> 4.7s
> 2G(524288) 15.5s 2088s
> 17.7s
>
Thanks for the patch! That's an impressive difference. You're changing
quite a few things in this patch, though. Can you send them as separate
patches so they can be reviewed one at a time? Is one of them in
particular making the difference? I suspect it's mostly the change to
test_bit(), and the rest is not necessary.
Cheers,
Tim.
> Signed-off-by??hongkaixing<hongkaixing@xxxxxxxxxx>,shizhen<bicky.shi@xxxxxxxxxx>
>
> diff -r 052727b8165c -r 978daceef147 tools/libxc/xc_mem_paging.c
> --- a/tools/libxc/xc_mem_paging.c Thu Dec 29 17:08:24 2011 +0800
> +++ b/tools/libxc/xc_mem_paging.c Thu Dec 29 19:41:39 2011 +0800
> @@ -73,6 +73,13 @@
> NULL, NULL, gfn);
> }
>
> +int xc_mem_paging_in(xc_interface *xch, domid_t domain_id, unsigned long gfn)
> +{
> + return xc_mem_event_control(xch, domain_id,
> + XEN_DOMCTL_MEM_EVENT_OP_PAGING_IN,
> + XEN_DOMCTL_MEM_EVENT_OP_PAGING,
> + NULL, NULL, gfn);
> +}
>
> /*
> * Local variables:
> diff -r 052727b8165c -r 978daceef147 tools/libxc/xenctrl.h
> --- a/tools/libxc/xenctrl.h Thu Dec 29 17:08:24 2011 +0800
> +++ b/tools/libxc/xenctrl.h Thu Dec 29 19:41:39 2011 +0800
> @@ -1841,6 +1841,7 @@
> int xc_mem_paging_prep(xc_interface *xch, domid_t domain_id, unsigned long
> gfn);
> int xc_mem_paging_resume(xc_interface *xch, domid_t domain_id,
> unsigned long gfn);
> +int xc_mem_paging_in(xc_interface *xch, domid_t domain_id,unsigned long
> gfn);
>
> int xc_mem_access_enable(xc_interface *xch, domid_t domain_id,
> void *shared_page, void *ring_page);
> diff -r 052727b8165c -r 978daceef147 tools/xenpaging/xenpaging.c
> --- a/tools/xenpaging/xenpaging.c Thu Dec 29 17:08:24 2011 +0800
> +++ b/tools/xenpaging/xenpaging.c Thu Dec 29 19:41:39 2011 +0800
> @@ -594,6 +594,13 @@
> return ret;
> }
>
> +static int paging_in_trigger_sync(xenpaging_t *paging,unsigned long gfn)
> +{
> + int rc = 0;
> + rc = xc_mem_paging_in(paging->xc_handle,
> paging->mem_event.domain_id,gfn);
> + return rc;
> +}
This function is
> +
> int main(int argc, char *argv[])
> {
> struct sigaction act;
> @@ -605,6 +612,9 @@
> int i;
> int rc = -1;
> int rc1;
> + int request_count = 0;
> + unsigned long page_in_start_gfn = 0;
> + unsigned long real_page = 0;
> xc_interface *xch;
>
> int open_flags = O_CREAT | O_TRUNC | O_RDWR;
> @@ -773,24 +783,51 @@
> /* Write all pages back into the guest */
> if ( interrupted == SIGTERM || interrupted == SIGINT )
> {
> - int num = 0;
> + request_count = 0;
> for ( i = 0; i < paging->domain_info->max_pages; i++ )
> {
> - if ( test_bit(i, paging->bitmap) )
> + real_page = i + page_in_start_gfn;
> + real_page %= paging->domain_info->max_pages;
> + if ( test_bit(real_page, paging->bitmap) )
> {
> - paging->pagein_queue[num] = i;
> - num++;
> - if ( num == XENPAGING_PAGEIN_QUEUE_SIZE )
> - break;
> + rc = paging_in_trigger_sync(paging,real_page);
> + if ( 0 == rc )
> + {
> + request_count++;
> + /* If page_in requests up to 32 then handle them */
> + if( request_count >= 32 )
> + {
> + page_in_start_gfn=real_page + 1;
> + break;
> + }
> + }
> + else
> + {
> + /* If IO ring is full then handle requests to free
> space */
> + if( ENOSPC == errno )
> + {
> + page_in_start_gfn = real_page;
> + break;
> + }
> + /* If p2mt is not p2m_is_paging,then clear bitmap;
> + * e.g. a page is paged then it is dropped by balloon.
> + */
> + else if ( EINVAL == errno )
> + {
> + clear_bit(i,paging->bitmap);
> + policy_notify_paged_in(i);
> + }
> + /* If hypercall fails then go to teardown xenpaging
> */
> + else
> + {
> + ERROR("Error paging in page");
> + goto out;
> + }
> + }
> }
> }
> - /*
> - * One more round if there are still pages to process.
> - * If no more pages to process, exit loop.
> - */
> - if ( num )
> - page_in_trigger();
> - else if ( i == paging->domain_info->max_pages )
> + if( (i==paging->domain_info->max_pages) &&
> + !RING_HAS_UNCONSUMED_REQUESTS(&paging->mem_event.back_ring) )
> break;
> }
> else
> diff -r 052727b8165c -r 978daceef147 xen/arch/x86/mm/mem_paging.c
> --- a/xen/arch/x86/mm/mem_paging.c Thu Dec 29 17:08:24 2011 +0800
> +++ b/xen/arch/x86/mm/mem_paging.c Thu Dec 29 19:41:39 2011 +0800
> @@ -57,7 +57,14 @@
> return 0;
> }
> break;
> -
> +
> + case XEN_DOMCTL_MEM_EVENT_OP_PAGING_IN:
> + {
> + unsigned long gfn = mec->gfn;
> + return p2m_mem_paging_populate(d, gfn);
> + }
> + break;
> +
> default:
> return -ENOSYS;
> break;
> diff -r 052727b8165c -r 978daceef147 xen/arch/x86/mm/p2m.c
> --- a/xen/arch/x86/mm/p2m.c Thu Dec 29 17:08:24 2011 +0800
> +++ b/xen/arch/x86/mm/p2m.c Thu Dec 29 19:41:39 2011 +0800
> @@ -874,7 +874,7 @@
> * already sent to the pager. In this case the caller has to try again until
> the
> * gfn is fully paged in again.
> */
> -void p2m_mem_paging_populate(struct domain *d, unsigned long gfn)
> +int p2m_mem_paging_populate(struct domain *d, unsigned long gfn)
> {
> struct vcpu *v = current;
> mem_event_request_t req;
> @@ -882,10 +882,12 @@
> p2m_access_t a;
> mfn_t mfn;
> struct p2m_domain *p2m = p2m_get_hostp2m(d);
> + int ret;
>
> /* Check that there's space on the ring for this request */
> + ret = -ENOSPC;
> if ( mem_event_check_ring(d, &d->mem_paging) )
> - return;
> + goto out;
>
> memset(&req, 0, sizeof(req));
> req.type = MEM_EVENT_TYPE_PAGING;
> @@ -905,19 +907,27 @@
> }
> p2m_unlock(p2m);
>
> + ret = -EINVAL;
> /* Pause domain if request came from guest and gfn has paging type */
> - if ( p2m_is_paging(p2mt) && v->domain->domain_id == d->domain_id )
> + if ( p2m_is_paging(p2mt) && v->domain->domain_id == d->domain_id )
> {
> vcpu_pause_nosync(v);
> req.flags |= MEM_EVENT_FLAG_VCPU_PAUSED;
> }
> /* No need to inform pager if the gfn is not in the page-out path */
> - else if ( p2mt != p2m_ram_paging_out && p2mt != p2m_ram_paged )
> + else if ( p2mt == p2m_ram_paging_in_start || p2mt == p2m_ram_paging_in )
> {
> /* gfn is already on its way back and vcpu is not paused */
> mem_event_put_req_producers(&d->mem_paging);
> - return;
> + return 0;
> }
> + else if ( !p2m_is_paging(p2mt) )
> + {
> + /* please clear the bit in paging->bitmap; */
> + mem_event_put_req_producers(&d->mem_paging);
> + goto out;
> + }
> +
>
> /* Send request to pager */
> req.gfn = gfn;
> @@ -925,8 +935,13 @@
> req.vcpu_id = v->vcpu_id;
>
> mem_event_put_request(d, &d->mem_paging, &req);
> +
> + ret = 0;
> + out:
> + return ret;
> }
>
> +
> /**
> * p2m_mem_paging_prep - Allocate a new page for the guest
> * @d: guest domain
> diff -r 052727b8165c -r 978daceef147 xen/include/asm-x86/p2m.h
> --- a/xen/include/asm-x86/p2m.h Thu Dec 29 17:08:24 2011 +0800
> +++ b/xen/include/asm-x86/p2m.h Thu Dec 29 19:41:39 2011 +0800
> @@ -485,7 +485,7 @@
> /* Tell xenpaging to drop a paged out frame */
> void p2m_mem_paging_drop_page(struct domain *d, unsigned long gfn);
> /* Start populating a paged out frame */
> -void p2m_mem_paging_populate(struct domain *d, unsigned long gfn);
> +int p2m_mem_paging_populate(struct domain *d, unsigned long gfn);
> /* Prepare the p2m for paging a frame in */
> int p2m_mem_paging_prep(struct domain *d, unsigned long gfn);
> /* Resume normal operation (in case a domain was paused) */
> diff -r 052727b8165c -r 978daceef147 xen/include/public/domctl.h
> --- a/xen/include/public/domctl.h Thu Dec 29 17:08:24 2011 +0800
> +++ b/xen/include/public/domctl.h Thu Dec 29 19:41:39 2011 +0800
> @@ -721,6 +721,7 @@
> #define XEN_DOMCTL_MEM_EVENT_OP_PAGING_EVICT 3
> #define XEN_DOMCTL_MEM_EVENT_OP_PAGING_PREP 4
> #define XEN_DOMCTL_MEM_EVENT_OP_PAGING_RESUME 5
> +#define XEN_DOMCTL_MEM_EVENT_OP_PAGING_IN 6
>
> /*
> * Access permissions.
>
> _______________________________________________
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> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
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