From: Baoquan He <bhe@redhat.com>
To: Mike Rapoport <rppt@linux.ibm.com>, Michal Hocko <mhocko@kernel.org>
Cc: Hoan Tran <Hoan@os.amperecomputing.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Oscar Salvador <osalvador@suse.de>,
Pavel Tatashin <pavel.tatashin@microsoft.com>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"David S. Miller" <davem@davemloft.net>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
"open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
sparclinux@vger.kernel.org, x86@kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
lho@amperecomputing.com, mmorana@amperecomputing.com
Subject: Re: [PATCH RFC] mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP (was: Re: [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA)
Date: Thu, 9 Apr 2020 22:41:19 +0800 [thread overview]
Message-ID: <20200409144119.GE2129@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20200402080144.GK22681@dhcp22.suse.cz>
On 04/02/20 at 10:01am, Michal Hocko wrote:
> On Wed 01-04-20 10:51:55, Mike Rapoport wrote:
> > Hi,
> >
> > On Wed, Apr 01, 2020 at 01:42:27PM +0800, Baoquan He wrote:
> [...]
> > > From above information, we can remove HAVE_MEMBLOCK_NODE_MAP, and
> > > replace it with CONFIG_NUMA. That sounds more sensible to store nid into
> > > memblock when NUMA support is enabled.
> >
> > Replacing CONFIG_HAVE_MEMBLOCK_NODE_MAP with CONFIG_NUMA will work, but
> > this will not help cleaning up the whole node/zone initialization mess and
> > we'll be stuck with two implementations.
>
> Yeah, this is far from optimal.
>
> > The overhead of enabling HAVE_MEMBLOCK_NODE_MAP is only for init time as
> > most architectures will anyway discard the entire memblock, so having it in
> > a UMA arch won't be a problem. The only exception is arm that uses
> > memblock for pfn_valid(), here we may also think about a solution to
> > compensate the addition of nid to the memblock structures.
>
> Well, we can make memblock_region->nid defined only for CONFIG_NUMA.
> memblock_get_region_node would then unconditionally return 0 on UMA.
> Essentially the same way we do NUMA for other MM code. I only see few
> direct usage of region->nid.
Checked code again, seems HAVE_MEMBLOCK_NODE_MAP is selected directly in
all ARCHes which support it. Means HAVE_MEMBLOCK_NODE_MAP is enabled by
default on those ARCHes, and has no dependency on CONFIG_NUMA at all.
E.g on x86, it just calls free_area_init_nodes() in generic code path,
while free_area_init_nodes() is defined in CONFIG_HAVE_MEMBLOCK_NODE_MAP
ifdeffery scope. So I tend to agree with Mike to remove
HAVE_MEMBLOCK_NODE_MAP firstly on all ARCHes. We can check if it's worth
only defining memblock_region->nid for CONFIG_NUMA case after
HAVE_MEMBLOCK_NODE_MAP is removed.
config X86
def_bool y
...
select HAVE_MEMBLOCK_NODE_MAP
...
next prev parent reply other threads:[~2020-04-09 14:41 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-28 18:31 [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA Hoan Tran
2020-03-28 18:31 ` [PATCH v3 1/5] " Hoan Tran
2020-03-28 18:31 ` [PATCH v3 2/5] powerpc: Kconfig: Remove CONFIG_NODES_SPAN_OTHER_NODES Hoan Tran
2020-03-28 18:31 ` [PATCH v3 3/5] x86: " Hoan Tran
2020-03-28 18:31 ` [PATCH v3 4/5] sparc: " Hoan Tran
2020-03-28 18:31 ` [PATCH v3 5/5] s390: " Hoan Tran
2020-03-29 0:19 ` [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA Baoquan He
2020-03-30 7:44 ` Michal Hocko
2020-03-30 8:04 ` Baoquan He
2020-03-30 7:42 ` Michal Hocko
2020-03-30 8:16 ` Baoquan He
2020-03-30 8:28 ` Baoquan He
2020-03-30 9:21 ` Mike Rapoport
2020-03-30 9:58 ` Michal Hocko
2020-03-30 10:26 ` Mike Rapoport
2020-03-30 10:43 ` Baoquan He
2020-03-31 21:56 ` [PATCH RFC] mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP (was: Re: [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA) Mike Rapoport
2020-04-01 5:42 ` Baoquan He
2020-04-01 7:51 ` Mike Rapoport
2020-04-02 8:01 ` Michal Hocko
2020-04-09 14:41 ` Baoquan He [this message]
2020-04-09 15:33 ` Michal Hocko
2020-04-10 6:46 ` Baoquan He
2020-03-30 9:26 ` [PATCH v3 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA Baoquan He
2020-03-30 17:51 ` Mike Rapoport
2020-03-30 18:23 ` Michal Hocko
2020-03-31 8:14 ` Mike Rapoport
2020-03-31 8:55 ` Michal Hocko
2020-03-31 14:03 ` Baoquan He
2020-03-31 14:21 ` Michal Hocko
2020-03-31 14:31 ` Baoquan He
2020-04-03 4:46 ` Hoan Tran
2020-04-03 7:09 ` Baoquan He
2020-04-03 16:36 ` Hoan Tran
2020-04-09 16:27 ` Mike Rapoport
2020-04-10 6:50 ` Baoquan He
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