From: David Hildenbrand <david@redhat.com> To: Will Deacon <will@kernel.org>, Chris Goldsworthy <quic_cgoldswo@quicinc.com> Cc: Catalin Marinas <catalin.marinas@arm.com>, Andrew Morton <akpm@linux-foundation.org>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Sudarshan Rajagopalan <quic_sudaraja@quicinc.com> Subject: Re: [RFC] arm64: mm: update max_pfn after memory hotplug Date: Wed, 29 Sep 2021 12:29:32 +0200 [thread overview] Message-ID: <13f56b37-afc7-bf6f-d544-8d6433588bf9@redhat.com> (raw) In-Reply-To: <20210929101028.GB21057@willie-the-truck> On 29.09.21 12:10, Will Deacon wrote: > On Thu, Sep 23, 2021 at 03:54:48PM -0700, Chris Goldsworthy wrote: >> From: Sudarshan Rajagopalan <quic_sudaraja@quicinc.com> >> >> After new memory blocks have been hotplugged, max_pfn and max_low_pfn >> needs updating to reflect on new PFNs being hot added to system. >> >> Signed-off-by: Sudarshan Rajagopalan <quic_sudaraja@quicinc.com> >> Signed-off-by: Chris Goldsworthy <quic_cgoldswo@quicinc.com> >> --- >> arch/arm64/mm/mmu.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index cfd9deb..fd85b51 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -1499,6 +1499,11 @@ int arch_add_memory(int nid, u64 start, u64 size, >> if (ret) >> __remove_pgd_mapping(swapper_pg_dir, >> __phys_to_virt(start), size); >> + else { >> + max_pfn = PFN_UP(start + size); >> + max_low_pfn = max_pfn; >> + } > > We use 'max_pfn' as part of the argument to set_max_mapnr(). Does that need > updating as well? > > Do we have sufficient locking to ensure nobody is looking at max_pfn or > max_low_pfn while we update them? Only the write side is protected by memory hotplug locking. The read side is lockless -- just like all of the other pfn_to_online_page() machinery. > > Will > -- Thanks, David / dhildenb
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com> To: Will Deacon <will@kernel.org>, Chris Goldsworthy <quic_cgoldswo@quicinc.com> Cc: Catalin Marinas <catalin.marinas@arm.com>, Andrew Morton <akpm@linux-foundation.org>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Sudarshan Rajagopalan <quic_sudaraja@quicinc.com> Subject: Re: [RFC] arm64: mm: update max_pfn after memory hotplug Date: Wed, 29 Sep 2021 12:29:32 +0200 [thread overview] Message-ID: <13f56b37-afc7-bf6f-d544-8d6433588bf9@redhat.com> (raw) In-Reply-To: <20210929101028.GB21057@willie-the-truck> On 29.09.21 12:10, Will Deacon wrote: > On Thu, Sep 23, 2021 at 03:54:48PM -0700, Chris Goldsworthy wrote: >> From: Sudarshan Rajagopalan <quic_sudaraja@quicinc.com> >> >> After new memory blocks have been hotplugged, max_pfn and max_low_pfn >> needs updating to reflect on new PFNs being hot added to system. >> >> Signed-off-by: Sudarshan Rajagopalan <quic_sudaraja@quicinc.com> >> Signed-off-by: Chris Goldsworthy <quic_cgoldswo@quicinc.com> >> --- >> arch/arm64/mm/mmu.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index cfd9deb..fd85b51 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -1499,6 +1499,11 @@ int arch_add_memory(int nid, u64 start, u64 size, >> if (ret) >> __remove_pgd_mapping(swapper_pg_dir, >> __phys_to_virt(start), size); >> + else { >> + max_pfn = PFN_UP(start + size); >> + max_low_pfn = max_pfn; >> + } > > We use 'max_pfn' as part of the argument to set_max_mapnr(). Does that need > updating as well? > > Do we have sufficient locking to ensure nobody is looking at max_pfn or > max_low_pfn while we update them? Only the write side is protected by memory hotplug locking. The read side is lockless -- just like all of the other pfn_to_online_page() machinery. > > Will > -- Thanks, David / dhildenb _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-09-29 10:29 UTC|newest] Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-23 22:54 [RFC] arm64: mm: update max_pfn after memory hotplug Chris Goldsworthy 2021-09-23 22:54 ` Chris Goldsworthy 2021-09-23 22:54 ` Chris Goldsworthy 2021-09-23 22:54 ` Chris Goldsworthy 2021-09-24 2:47 ` Florian Fainelli 2021-09-24 2:47 ` Florian Fainelli 2021-09-24 8:17 ` David Hildenbrand 2021-09-24 8:17 ` David Hildenbrand 2021-09-24 20:52 ` Chris Goldsworthy 2021-09-24 20:52 ` Chris Goldsworthy 2021-09-25 0:36 ` Sudarshan Rajagopalan 2021-09-25 0:36 ` Sudarshan Rajagopalan 2021-09-27 15:51 ` David Hildenbrand 2021-09-27 15:51 ` David Hildenbrand 2021-09-27 23:22 ` Georgi Djakov 2021-09-27 23:22 ` Georgi Djakov 2021-09-28 6:12 ` Chris Goldsworthy 2021-09-28 6:12 ` Chris Goldsworthy 2021-09-28 7:33 ` David Hildenbrand 2021-09-28 7:33 ` David Hildenbrand 2021-09-27 17:22 ` Georgi Djakov 2021-09-27 17:22 ` Georgi Djakov 2021-09-27 17:34 ` David Hildenbrand 2021-09-27 17:34 ` David Hildenbrand 2021-09-27 20:00 ` Georgi Djakov 2021-09-27 20:00 ` Georgi Djakov 2021-09-27 20:14 ` David Hildenbrand 2021-09-27 20:14 ` David Hildenbrand 2021-09-27 23:01 ` Georgi Djakov 2021-09-27 23:01 ` Georgi Djakov 2021-09-29 10:10 ` Will Deacon 2021-09-29 10:10 ` Will Deacon 2021-09-29 10:29 ` David Hildenbrand [this message] 2021-09-29 10:29 ` David Hildenbrand 2021-09-29 10:42 ` Will Deacon 2021-09-29 10:42 ` Will Deacon 2021-09-29 10:49 ` David Hildenbrand 2021-09-29 10:49 ` David Hildenbrand 2021-09-29 11:03 ` Will Deacon 2021-09-29 11:03 ` Will Deacon 2021-09-29 12:09 ` David Hildenbrand 2021-09-29 12:09 ` David Hildenbrand 2021-09-29 12:51 ` Will Deacon 2021-09-29 12:51 ` Will Deacon
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=13f56b37-afc7-bf6f-d544-8d6433588bf9@redhat.com \ --to=david@redhat.com \ --cc=akpm@linux-foundation.org \ --cc=catalin.marinas@arm.com \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=quic_cgoldswo@quicinc.com \ --cc=quic_sudaraja@quicinc.com \ --cc=will@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.