| Message ID | 1454955189-2020-1-git-send-email-tim.gardner@canonical.com |
|---|---|
| State | New |
| Headers | show |
ACK for Vivid/Wily SRU. (I will also queue up this backport for 3.19- and 4.2- stable.) -Kamal
On Mon, Feb 08, 2016 at 11:13:09AM -0700, tim.gardner@canonical.com wrote: > From: David Vrabel <david.vrabel@citrix.com> > > BugLink: http://bugs.launchpad.net/bugs/1542941 > > With commit 633d6f17cd91ad5bf2370265946f716e42d388c6 (x86/xen: prepare > p2m list for memory hotplug) the P2M may be sized to accomdate a much > larger amount of memory than the domain currently has. > > When saving a domain, the toolstack must scan all the P2M looking for > populated pages. This results in a performance regression due to the > unnecessary scanning. > > Instead of reporting (via shared_info) the maximum possible size of > the P2M, hint at the last PFN which might be populated. This hint is > increased as new leaves are added to the P2M (in the expectation that > they will be used for populated entries). > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> > Cc: <stable@vger.kernel.org> # 4.0+ > (back ported from commit 98dd166ea3a3c3b57919e20d9b0d1237fcd0349d) I think that is in a non-standard form. Using the standard forms helps things like the autotriager which read them. > Signed-off-by: Tim Gardner <tim.gardner@canonical.com> > > Conflicts: > arch/x86/xen/p2m.c I'd move those two up between the (backported ...) and Tim's SOB. > --- > arch/x86/xen/p2m.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c > index 8b7f18e..912b123 100644 > --- a/arch/x86/xen/p2m.c > +++ b/arch/x86/xen/p2m.c > @@ -108,6 +108,15 @@ static unsigned long *p2m_identity; > static pte_t *p2m_missing_pte; > static pte_t *p2m_identity_pte; > > +/* > + * Hint at last populated PFN. > + * > + * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack > + * can avoid scanning the whole P2M (which may be sized to account for > + * hotplugged memory). > + */ > +static unsigned long xen_p2m_last_pfn; > + > static inline unsigned p2m_top_index(unsigned long pfn) > { > BUG_ON(pfn >= MAX_P2M_PFN); > @@ -262,7 +271,7 @@ void xen_setup_mfn_list_list(void) > > HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = > virt_to_mfn(p2m_top_mfn); > - HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; > + HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; > } > > /* Set up p2m_top to point to the domain-builder provided p2m pages */ > @@ -394,6 +403,8 @@ void __init xen_vmalloc_p2m_tree(void) > static struct vm_struct vm; > unsigned long p2m_limit; > > + xen_p2m_last_pfn = xen_max_p2m_pfn; > + > p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; > vm.flags = VM_ALLOC; > vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), > @@ -590,6 +601,12 @@ static bool alloc_p2m(unsigned long pfn) > free_p2m_page(p2m); > } > > + /* Expanded the p2m? */ > + if (pfn > xen_p2m_last_pfn) { > + xen_p2m_last_pfn = pfn; > + HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; > + } > + > return true; > } > Acked-by: Andy Whitcroft <apw@canonical.com> -apw
Applied to [V,W] master-next. -Kamal
On 02/09/2016 09:47 AM, Andy Whitcroft wrote: > On Mon, Feb 08, 2016 at 11:13:09AM -0700, tim.gardner@canonical.com wrote: >> From: David Vrabel <david.vrabel@citrix.com> >> >> BugLink: http://bugs.launchpad.net/bugs/1542941 >> >> With commit 633d6f17cd91ad5bf2370265946f716e42d388c6 (x86/xen: prepare >> p2m list for memory hotplug) the P2M may be sized to accomdate a much >> larger amount of memory than the domain currently has. >> >> When saving a domain, the toolstack must scan all the P2M looking for >> populated pages. This results in a performance regression due to the >> unnecessary scanning. >> >> Instead of reporting (via shared_info) the maximum possible size of >> the P2M, hint at the last PFN which might be populated. This hint is >> increased as new leaves are added to the P2M (in the expectation that >> they will be used for populated entries). >> >> Signed-off-by: David Vrabel <david.vrabel@citrix.com> >> Cc: <stable@vger.kernel.org> # 4.0+ >> (back ported from commit 98dd166ea3a3c3b57919e20d9b0d1237fcd0349d) > > I think that is in a non-standard form. Using the standard forms helps > things like the autotriager which read them. > What is standard form ? 'backported' v.s. 'back ported' ?
On Tue, Feb 09, 2016 at 12:40:20PM -0800, Tim Gardner wrote: > On 02/09/2016 09:47 AM, Andy Whitcroft wrote: > > On Mon, Feb 08, 2016 at 11:13:09AM -0700, tim.gardner@canonical.com wrote: > >> From: David Vrabel <david.vrabel@citrix.com> > >> > >> BugLink: http://bugs.launchpad.net/bugs/1542941 > >> > >> With commit 633d6f17cd91ad5bf2370265946f716e42d388c6 (x86/xen: prepare > >> p2m list for memory hotplug) the P2M may be sized to accomdate a much > >> larger amount of memory than the domain currently has. > >> > >> When saving a domain, the toolstack must scan all the P2M looking for > >> populated pages. This results in a performance regression due to the > >> unnecessary scanning. > >> > >> Instead of reporting (via shared_info) the maximum possible size of > >> the P2M, hint at the last PFN which might be populated. This hint is > >> increased as new leaves are added to the P2M (in the expectation that > >> they will be used for populated entries). > >> > >> Signed-off-by: David Vrabel <david.vrabel@citrix.com> > >> Cc: <stable@vger.kernel.org> # 4.0+ > >> (back ported from commit 98dd166ea3a3c3b57919e20d9b0d1237fcd0349d) > > > > I think that is in a non-standard form. Using the standard forms helps > > things like the autotriager which read them. > > > > What is standard form ? 'backported' v.s. 'back ported' ? > -- > Tim Gardner tim.gardner@canonical.com > > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team Looking at some of our git repos we have been using "backported".
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 8b7f18e..912b123 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -108,6 +108,15 @@ static unsigned long *p2m_identity; static pte_t *p2m_missing_pte; static pte_t *p2m_identity_pte; +/* + * Hint at last populated PFN. + * + * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack + * can avoid scanning the whole P2M (which may be sized to account for + * hotplugged memory). + */ +static unsigned long xen_p2m_last_pfn; + static inline unsigned p2m_top_index(unsigned long pfn) { BUG_ON(pfn >= MAX_P2M_PFN); @@ -262,7 +271,7 @@ void xen_setup_mfn_list_list(void) HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = virt_to_mfn(p2m_top_mfn); - HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn; + HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; } /* Set up p2m_top to point to the domain-builder provided p2m pages */ @@ -394,6 +403,8 @@ void __init xen_vmalloc_p2m_tree(void) static struct vm_struct vm; unsigned long p2m_limit; + xen_p2m_last_pfn = xen_max_p2m_pfn; + p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; vm.flags = VM_ALLOC; vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), @@ -590,6 +601,12 @@ static bool alloc_p2m(unsigned long pfn) free_p2m_page(p2m); } + /* Expanded the p2m? */ + if (pfn > xen_p2m_last_pfn) { + xen_p2m_last_pfn = pfn; + HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn; + } + return true; }