Re: [Xen-devel] [PATCH 2/2] xen: before ballooning hotplugged memory, set frames to invalid
On Thu, Mar 19, 2015 at 06:22:06PM +0100, Juergen Gross wrote: > On 03/19/2015 05:21 PM, Daniel Kiper wrote: > >On Thu, Mar 19, 2015 at 03:31:02PM +0100, Juergen Gross wrote: > >>Commit 25b884a83d487fd62c3de7ac1ab5549979188482 ("x86/xen: set > >>regions above the end of RAM as 1:1") introduced a regression. > >> > >>To be able to add memory pages which were added via memory hotplug to > >>a pv domain, the pages must be "invalid" instead of "identity" in the > >>p2m list before they can be added. > >> > >>Suggested-by: David Vrabel > >>Signed-off-by: Juergen Gross > >>--- > >> drivers/xen/balloon.c | 13 +++-- > >> 1 file changed, 11 insertions(+), 2 deletions(-) > >> > >>diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > >>index 0b52d92..52e331f 100644 > >>--- a/drivers/xen/balloon.c > >>+++ b/drivers/xen/balloon.c > >>@@ -221,15 +221,24 @@ static bool balloon_is_inflated(void) > >> > >> static enum bp_state reserve_additional_memory(long credit) > >> { > >>- int nid, rc; > >>+ int nid, rc = 0; > >>u64 hotplug_start_paddr; > >>unsigned long balloon_hotplug = credit; > >>+ unsigned long pfn; > >> > >>hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); > >>balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); > >>nid = memory_add_physaddr_to_nid(hotplug_start_paddr); > >> > >>- rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << > >>PAGE_SHIFT); > >>+ for (pfn = PFN_DOWN(hotplug_start_paddr); > >>+!rc && pfn < PFN_DOWN(hotplug_start_paddr) + balloon_hotplug; > >>+pfn++) > >>+ if (!set_phys_to_machine(pfn, INVALID_P2M_ENTRY)) > > > >rc = set_phys_to_machine(pfn, INVALID_P2M_ENTRY)? > > Not really. set_phys_to_machine returns false on failure... > > > > >>+ rc = 1; > > > >I do not think that this stuff is needed for HVM or PVH guests. > > True. > > > > >>+ if (!rc) > >>+ rc = add_memory(nid, hotplug_start_paddr, > >>+ balloon_hotplug << PAGE_SHIFT); > >> > >>if (rc) { > >>pr_warn("Cannot add additional memory (%i)\n", rc); > > > >It will be nice to know what part of infrastructure failed. > >Could you create separate pr_warn() message for set_phys_to_machine()? > > Value 1 for rc is the indicator for that case. Well... Personally I prefer explicit messages telling what happened than something which requires digging in a code to understand a problem. Additionally, I think that we should use negative numbers (as David suggested) to signal an error. Most of kernel stuff work in that way. Daniel ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH 2/2] xen: before ballooning hotplugged memory, set frames to invalid
On 19/03/15 17:19, Juergen Gross wrote: > On 03/19/2015 05:18 PM, David Vrabel wrote: >> On 19/03/15 14:31, Juergen Gross wrote: >>> Commit 25b884a83d487fd62c3de7ac1ab5549979188482 ("x86/xen: set >>> regions above the end of RAM as 1:1") introduced a regression. >>> >>> To be able to add memory pages which were added via memory hotplug to >>> a pv domain, the pages must be "invalid" instead of "identity" in the >>> p2m list before they can be added. >> [...] >>> --- a/drivers/xen/balloon.c >>> +++ b/drivers/xen/balloon.c >>> @@ -221,15 +221,24 @@ static bool balloon_is_inflated(void) >>> >>> static enum bp_state reserve_additional_memory(long credit) >>> { >>> -int nid, rc; >>> +int nid, rc = 0; >>> u64 hotplug_start_paddr; >>> unsigned long balloon_hotplug = credit; >>> +unsigned long pfn; >>> >>> hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); >>> balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); >>> nid = memory_add_physaddr_to_nid(hotplug_start_paddr); >>> >>> -rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << >>> PAGE_SHIFT); >>> +for (pfn = PFN_DOWN(hotplug_start_paddr); >>> + !rc && pfn < PFN_DOWN(hotplug_start_paddr) + balloon_hotplug; >>> + pfn++) >>> +if (!set_phys_to_machine(pfn, INVALID_P2M_ENTRY)) >>> +rc = 1; >> >> rc = -ENOMEM; > > I used the value 1 on purpose to be able to identify the case by the > value printed in the warning below. Ok. > >> break; > > Why? !rc is already tested in the for() clause. I prefer an explicit break. >>> + >>> +if (!rc) >>> +rc = add_memory(nid, hotplug_start_paddr, >>> +balloon_hotplug << PAGE_SHIFT); >> >> Use else here. > > Huh? I want the message to be printed if either set_phys_to_machine() > or add_memory() failed. Ok. David ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH 2/2] xen: before ballooning hotplugged memory, set frames to invalid
On 03/19/2015 05:21 PM, Daniel Kiper wrote: On Thu, Mar 19, 2015 at 03:31:02PM +0100, Juergen Gross wrote: Commit 25b884a83d487fd62c3de7ac1ab5549979188482 ("x86/xen: set regions above the end of RAM as 1:1") introduced a regression. To be able to add memory pages which were added via memory hotplug to a pv domain, the pages must be "invalid" instead of "identity" in the p2m list before they can be added. Suggested-by: David Vrabel Signed-off-by: Juergen Gross --- drivers/xen/balloon.c | 13 +++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 0b52d92..52e331f 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -221,15 +221,24 @@ static bool balloon_is_inflated(void) static enum bp_state reserve_additional_memory(long credit) { - int nid, rc; + int nid, rc = 0; u64 hotplug_start_paddr; unsigned long balloon_hotplug = credit; + unsigned long pfn; hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); nid = memory_add_physaddr_to_nid(hotplug_start_paddr); - rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT); + for (pfn = PFN_DOWN(hotplug_start_paddr); +!rc && pfn < PFN_DOWN(hotplug_start_paddr) + balloon_hotplug; +pfn++) + if (!set_phys_to_machine(pfn, INVALID_P2M_ENTRY)) rc = set_phys_to_machine(pfn, INVALID_P2M_ENTRY)? Not really. set_phys_to_machine returns false on failure... + rc = 1; I do not think that this stuff is needed for HVM or PVH guests. True. + if (!rc) + rc = add_memory(nid, hotplug_start_paddr, + balloon_hotplug << PAGE_SHIFT); if (rc) { pr_warn("Cannot add additional memory (%i)\n", rc); It will be nice to know what part of infrastructure failed. Could you create separate pr_warn() message for set_phys_to_machine()? Value 1 for rc is the indicator for that case. Juergen ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH 2/2] xen: before ballooning hotplugged memory, set frames to invalid
On 03/19/2015 05:18 PM, David Vrabel wrote: On 19/03/15 14:31, Juergen Gross wrote: Commit 25b884a83d487fd62c3de7ac1ab5549979188482 ("x86/xen: set regions above the end of RAM as 1:1") introduced a regression. To be able to add memory pages which were added via memory hotplug to a pv domain, the pages must be "invalid" instead of "identity" in the p2m list before they can be added. [...] --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -221,15 +221,24 @@ static bool balloon_is_inflated(void) static enum bp_state reserve_additional_memory(long credit) { - int nid, rc; + int nid, rc = 0; u64 hotplug_start_paddr; unsigned long balloon_hotplug = credit; + unsigned long pfn; hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); nid = memory_add_physaddr_to_nid(hotplug_start_paddr); - rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << PAGE_SHIFT); + for (pfn = PFN_DOWN(hotplug_start_paddr); +!rc && pfn < PFN_DOWN(hotplug_start_paddr) + balloon_hotplug; +pfn++) + if (!set_phys_to_machine(pfn, INVALID_P2M_ENTRY)) + rc = 1; rc = -ENOMEM; I used the value 1 on purpose to be able to identify the case by the value printed in the warning below. break; Why? !rc is already tested in the for() clause. + + if (!rc) + rc = add_memory(nid, hotplug_start_paddr, + balloon_hotplug << PAGE_SHIFT); Use else here. Huh? I want the message to be printed if either set_phys_to_machine() or add_memory() failed. if (rc) { pr_warn("Cannot add additional memory (%i)\n", rc); Juergen ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH 2/2] xen: before ballooning hotplugged memory, set frames to invalid
On Thu, Mar 19, 2015 at 03:31:02PM +0100, Juergen Gross wrote: > Commit 25b884a83d487fd62c3de7ac1ab5549979188482 ("x86/xen: set > regions above the end of RAM as 1:1") introduced a regression. > > To be able to add memory pages which were added via memory hotplug to > a pv domain, the pages must be "invalid" instead of "identity" in the > p2m list before they can be added. > > Suggested-by: David Vrabel > Signed-off-by: Juergen Gross > --- > drivers/xen/balloon.c | 13 +++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > index 0b52d92..52e331f 100644 > --- a/drivers/xen/balloon.c > +++ b/drivers/xen/balloon.c > @@ -221,15 +221,24 @@ static bool balloon_is_inflated(void) > > static enum bp_state reserve_additional_memory(long credit) > { > - int nid, rc; > + int nid, rc = 0; > u64 hotplug_start_paddr; > unsigned long balloon_hotplug = credit; > + unsigned long pfn; > > hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); > balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); > nid = memory_add_physaddr_to_nid(hotplug_start_paddr); > > - rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << > PAGE_SHIFT); > + for (pfn = PFN_DOWN(hotplug_start_paddr); > + !rc && pfn < PFN_DOWN(hotplug_start_paddr) + balloon_hotplug; > + pfn++) > + if (!set_phys_to_machine(pfn, INVALID_P2M_ENTRY)) rc = set_phys_to_machine(pfn, INVALID_P2M_ENTRY)? > + rc = 1; I do not think that this stuff is needed for HVM or PVH guests. > + if (!rc) > + rc = add_memory(nid, hotplug_start_paddr, > + balloon_hotplug << PAGE_SHIFT); > > if (rc) { > pr_warn("Cannot add additional memory (%i)\n", rc); It will be nice to know what part of infrastructure failed. Could you create separate pr_warn() message for set_phys_to_machine()? Daniel ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH 2/2] xen: before ballooning hotplugged memory, set frames to invalid
On 19/03/15 14:31, Juergen Gross wrote: > Commit 25b884a83d487fd62c3de7ac1ab5549979188482 ("x86/xen: set > regions above the end of RAM as 1:1") introduced a regression. > > To be able to add memory pages which were added via memory hotplug to > a pv domain, the pages must be "invalid" instead of "identity" in the > p2m list before they can be added. [...] > --- a/drivers/xen/balloon.c > +++ b/drivers/xen/balloon.c > @@ -221,15 +221,24 @@ static bool balloon_is_inflated(void) > > static enum bp_state reserve_additional_memory(long credit) > { > - int nid, rc; > + int nid, rc = 0; > u64 hotplug_start_paddr; > unsigned long balloon_hotplug = credit; > + unsigned long pfn; > > hotplug_start_paddr = PFN_PHYS(SECTION_ALIGN_UP(max_pfn)); > balloon_hotplug = round_up(balloon_hotplug, PAGES_PER_SECTION); > nid = memory_add_physaddr_to_nid(hotplug_start_paddr); > > - rc = add_memory(nid, hotplug_start_paddr, balloon_hotplug << > PAGE_SHIFT); > + for (pfn = PFN_DOWN(hotplug_start_paddr); > + !rc && pfn < PFN_DOWN(hotplug_start_paddr) + balloon_hotplug; > + pfn++) > + if (!set_phys_to_machine(pfn, INVALID_P2M_ENTRY)) > + rc = 1; rc = -ENOMEM; break; > + > + if (!rc) > + rc = add_memory(nid, hotplug_start_paddr, > + balloon_hotplug << PAGE_SHIFT); Use else here. > if (rc) { > pr_warn("Cannot add additional memory (%i)\n", rc); > ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel