From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Joerg Roedel <jroedel@suse.de>, Andi Kleen <ak@linux.intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
Tom Lendacky <thomas.lendacky@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Varad Gautam <varad.gautam@suse.com>,
Dario Faggioli <dfaggioli@suse.com>,
x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev,
linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH 4/5] x86/mm: Provide helpers for unaccepted memory
Date: Thu, 12 Aug 2021 23:31:53 +0300 [thread overview]
Message-ID: <20210812203153.uoa7nx7w5zdsmzck@box.shutemov.name> (raw)
In-Reply-To: <67ce254c-aacc-43b6-d8d5-168ef9200f9e@intel.com>
On Tue, Aug 10, 2021 at 11:16:26AM -0700, Dave Hansen wrote:
> On 8/9/21 11:26 PM, Kirill A. Shutemov wrote:
> > +void accept_memory(phys_addr_t start, phys_addr_t end)
> > +{
> > + if (!boot_params.unaccepted_memory)
> > + return;
> > +
> > + spin_lock(&unaccepted_memory_lock);
> > + __accept_memory(start, end);
> > + spin_unlock(&unaccepted_memory_lock);
> > +}
>
> Isn't this taken in the:
>
> del_page_from_free_list()->
> clear_page_offline()->
> accept_memory()
>
> call path?
>
> That's underneath:
>
> spin_lock_irqsave(&zone->lock, flags);
>
> Which means that accept_memory() can happen from interrupt context. Is
> it always covered by another spin_lock_irqsave() which means that it can
> use a plain spin_lock()?
I didn't give it enough thought yet, but we always run under zone lock
which has to use spin_lock_irqsave() if it called from interrupt context.
Having said that I think it is good idea to move clear_page_offline() out
zone lock. It should help with allocation latency. Not sure how messy it
gets. Merging/splitting path looks complex and I'm not an expert in the
page allocator.
> If so, it would be nice to call out that logic. It *looks* like a
> spinlock that we would want to be spin_lock_irqsave().
--
Kirill A. Shutemov
next prev parent reply other threads:[~2021-08-12 20:31 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-10 6:26 [PATCH 0/5] x86: Impplement support for unaccepted memory Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 1/5] mm: Add " Kirill A. Shutemov
2021-08-10 7:48 ` David Hildenbrand
2021-08-10 15:02 ` Kirill A. Shutemov
2021-08-10 15:21 ` David Hildenbrand
2021-08-12 20:34 ` Kirill A. Shutemov
2021-08-10 18:13 ` Dave Hansen
2021-08-10 18:30 ` Andi Kleen
2021-08-10 18:56 ` Dave Hansen
2021-08-10 19:23 ` Andi Kleen
2021-08-10 19:46 ` Dave Hansen
2021-08-10 21:20 ` Andi Kleen
2021-08-12 8:19 ` Joerg Roedel
2021-08-12 14:14 ` Dave Hansen
2021-08-12 20:49 ` Kirill A. Shutemov
2021-08-12 20:59 ` Dave Hansen
2021-08-12 21:23 ` Kirill A. Shutemov
2021-08-13 14:49 ` Joerg Roedel
2021-08-17 15:00 ` David Hildenbrand
2021-08-19 9:55 ` Joerg Roedel
2021-08-19 10:06 ` David Hildenbrand
2021-08-10 20:50 ` Dave Hansen
2021-08-12 21:08 ` Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 2/5] efi/x86: Implement " Kirill A. Shutemov
2021-08-10 17:50 ` Dave Hansen
2021-08-12 21:14 ` Kirill A. Shutemov
2021-08-12 21:43 ` Dave Hansen
2021-08-10 18:30 ` Dave Hansen
2021-08-10 19:08 ` Kirill A. Shutemov
2021-08-10 19:19 ` Dave Hansen
2021-08-12 21:17 ` Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 3/5] x86/boot/compressed: Handle " Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 4/5] x86/mm: Provide helpers for " Kirill A. Shutemov
2021-08-10 18:16 ` Dave Hansen
2021-08-12 20:31 ` Kirill A. Shutemov [this message]
2021-08-10 6:26 ` [PATCH 5/5] x86/tdx: Unaccepted memory support Kirill A. Shutemov
2021-08-10 14:08 ` [PATCH 0/5] x86: Impplement support for unaccepted memory Dave Hansen
2021-08-10 15:15 ` Kirill A. Shutemov
2021-08-10 15:51 ` Dave Hansen
2021-08-10 17:31 ` Kirill A. Shutemov
2021-08-10 17:36 ` Dave Hansen
2021-08-10 17:51 ` Kirill A. Shutemov
2021-08-10 18:19 ` Dave Hansen
2021-08-10 18:39 ` Kirill A. Shutemov
2021-08-12 8:23 ` Joerg Roedel
2021-08-12 10:10 ` Kirill A. Shutemov
2021-08-12 19:33 ` Andi Kleen
2021-08-12 20:22 ` Kirill A. Shutemov
2021-08-13 14:56 ` Joerg Roedel
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