Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Sender: sudaraja=codeaurora.org@mg.codeaurora.org
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Date:   Fri, 16 Oct 2020 11:49:02 -0700
From:   Sudarshan Rajagopalan <sudaraja@codeaurora.org>
To:     Will Deacon <will@kernel.org>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Gavin Shan <gshan@redhat.com>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Steven Price <steven.price@arm.com>
Subject: Re: [PATCH v3] arm64/mm: add fallback option to allocate virtually
 contiguous memory
In-Reply-To: <20201015083605.GA4537@willie-the-truck>
References: <cover.1602722808.git.sudaraja@codeaurora.org>
 <d6c06f2ef39bbe6c715b2f6db76eb16155fdcee6.1602722808.git.sudaraja@codeaurora.org>
 <20201015083605.GA4537@willie-the-truck>
Message-ID: <541f79b6b5f3640c1e4978931ae93a38@codeaurora.org>
User-Agent: Roundcube Webmail/1.3.9
Precedence: bulk

On 2020-10-15 01:36, Will Deacon wrote:
> On Wed, Oct 14, 2020 at 05:51:23PM -0700, Sudarshan Rajagopalan wrote:
>> When section mappings are enabled, we allocate vmemmap pages from
>> physically continuous memory of size PMD_SIZE using
>> vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB
>> pressure. But when system is highly fragmented and memory blocks are
>> being hot-added at runtime, its possible that such physically 
>> continuous
>> memory allocations can fail. Rather than failing the memory hot-add
>> procedure, add a fallback option to allocate vmemmap pages from
>> discontinuous pages using vmemmap_populate_basepages().
>> 
>> Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org>
>> Reviewed-by: Gavin Shan <gshan@redhat.com>
>> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Anshuman Khandual <anshuman.khandual@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: Logan Gunthorpe <logang@deltatee.com>
>> Cc: David Hildenbrand <david@redhat.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Steven Price <steven.price@arm.com>
>> ---
>>  arch/arm64/mm/mmu.c | 7 +++++--
>>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> Please can you fix the subject? I have three copies of "PATCH v3" from
> different days in my inbox. I know it sounds trivial, but getting these
> little things right really helps with review, especially when it's 
> sitting
> amongst a sea of other patches.

Yes sure, sorry about that - will change it to "PATCH v4" to make it 
stand out from other patches.

> 
> Thanks,
> 
> Will


Sudarshan

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project