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Date: Thu, 19 Mar 2015 18:19:50 +0100 From: Juergen Gross <jgross@...e.com> To: David Vrabel <david.vrabel@...rix.com>, linux-kernel@...r.kernel.org, xen-devel@...ts.xensource.com, konrad.wilk@...cle.com, boris.ostrovsky@...cle.com, daniel.kiper@...cle.com Subject: 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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