From: Matthew Wilcox <willy@infradead.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Borislav Petkov <bp@alien8.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Mackerras <paulus@samba.org>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH v2 1/3] mm: vmalloc: Let user to control huge vmalloc default behavior
Date: Wed, 19 Jan 2022 13:48:13 +0000 [thread overview]
Message-ID: <YegWneON2voE9htO@casper.infradead.org> (raw)
In-Reply-To: <93db576e-9a62-ee98-5af2-a62f8386212c@huawei.com>
On Wed, Jan 19, 2022 at 09:44:20PM +0800, Kefeng Wang wrote:
>
> On 2022/1/19 21:22, Matthew Wilcox wrote:
> > On Wed, Jan 19, 2022 at 08:57:58PM +0800, Kefeng Wang wrote:
> > > Only parts of our products wants this feature, we add some interfaces which
> > > only
> > >
> > > alloc hugevmalloc for them, eg,
> > > vmap_hugepage/vmalloc_hugepage/remap_vmalloc_hugepage_range..
> > >
> > > for our products, but it's not the choice of most products, also add
> > > nohugevmalloc
> > >
> > > for most products is expensive, so this is the reason for adding the patch.
> > >
> > > more config/cmdline are more flexible for test/products，
> > But why do only some products want it? What goes wrong if all products
> > enable it? Features should be auto-tuning, not relying on admins to
> > understand them.
>
> Because this feature will use more memory for vmalloc/vmap, that's why we
> add some explicit
> interfaces as said above in our kernel to control the user.
Have you validated that? What sort of performance penalty do you see?
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Wilcox <willy@infradead.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-doc@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
linux-kernel@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>,
linux-mm@kvack.org, Will Deacon <will@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Paul Mackerras <paulus@samba.org>,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/3] mm: vmalloc: Let user to control huge vmalloc default behavior
Date: Wed, 19 Jan 2022 13:48:13 +0000 [thread overview]
Message-ID: <YegWneON2voE9htO@casper.infradead.org> (raw)
In-Reply-To: <93db576e-9a62-ee98-5af2-a62f8386212c@huawei.com>
On Wed, Jan 19, 2022 at 09:44:20PM +0800, Kefeng Wang wrote:
>
> On 2022/1/19 21:22, Matthew Wilcox wrote:
> > On Wed, Jan 19, 2022 at 08:57:58PM +0800, Kefeng Wang wrote:
> > > Only parts of our products wants this feature, we add some interfaces which
> > > only
> > >
> > > alloc hugevmalloc for them, eg,
> > > vmap_hugepage/vmalloc_hugepage/remap_vmalloc_hugepage_range..
> > >
> > > for our products, but it's not the choice of most products, also add
> > > nohugevmalloc
> > >
> > > for most products is expensive, so this is the reason for adding the patch.
> > >
> > > more config/cmdline are more flexible for test/products，
> > But why do only some products want it? What goes wrong if all products
> > enable it? Features should be auto-tuning, not relying on admins to
> > understand them.
>
> Because this feature will use more memory for vmalloc/vmap, that's why we
> add some explicit
> interfaces as said above in our kernel to control the user.
Have you validated that? What sort of performance penalty do you see?
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Wilcox <willy@infradead.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Borislav Petkov <bp@alien8.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Mackerras <paulus@samba.org>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH v2 1/3] mm: vmalloc: Let user to control huge vmalloc default behavior
Date: Wed, 19 Jan 2022 13:48:13 +0000 [thread overview]
Message-ID: <YegWneON2voE9htO@casper.infradead.org> (raw)
In-Reply-To: <93db576e-9a62-ee98-5af2-a62f8386212c@huawei.com>
On Wed, Jan 19, 2022 at 09:44:20PM +0800, Kefeng Wang wrote:
>
> On 2022/1/19 21:22, Matthew Wilcox wrote:
> > On Wed, Jan 19, 2022 at 08:57:58PM +0800, Kefeng Wang wrote:
> > > Only parts of our products wants this feature, we add some interfaces which
> > > only
> > >
> > > alloc hugevmalloc for them, eg,
> > > vmap_hugepage/vmalloc_hugepage/remap_vmalloc_hugepage_range..
> > >
> > > for our products, but it's not the choice of most products, also add
> > > nohugevmalloc
> > >
> > > for most products is expensive, so this is the reason for adding the patch.
> > >
> > > more config/cmdline are more flexible for test/products，
> > But why do only some products want it? What goes wrong if all products
> > enable it? Features should be auto-tuning, not relying on admins to
> > understand them.
>
> Because this feature will use more memory for vmalloc/vmap, that's why we
> add some explicit
> interfaces as said above in our kernel to control the user.
Have you validated that? What sort of performance penalty do you see?
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next prev parent reply other threads:[~2022-01-19 13:48 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-27 14:59 [PATCH v2 0/3] mm: support huge vmalloc mapping on arm64/x86 Kefeng Wang
2021-12-27 14:59 ` Kefeng Wang
2021-12-27 14:59 ` Kefeng Wang
2021-12-27 14:59 ` [PATCH v2 1/3] mm: vmalloc: Let user to control huge vmalloc default behavior Kefeng Wang
2021-12-27 14:59 ` Kefeng Wang
2021-12-27 14:59 ` Kefeng Wang
2022-01-18 2:52 ` Nicholas Piggin
2022-01-18 2:52 ` Nicholas Piggin
2022-01-18 2:52 ` Nicholas Piggin
2022-01-19 12:57 ` Kefeng Wang
2022-01-19 12:57 ` Kefeng Wang
2022-01-19 12:57 ` Kefeng Wang
2022-01-19 13:22 ` Matthew Wilcox
2022-01-19 13:22 ` Matthew Wilcox
2022-01-19 13:22 ` Matthew Wilcox
2022-01-19 13:44 ` Kefeng Wang
2022-01-19 13:44 ` Kefeng Wang
2022-01-19 13:44 ` Kefeng Wang
2022-01-19 13:48 ` Matthew Wilcox [this message]
2022-01-19 13:48 ` Matthew Wilcox
2022-01-19 13:48 ` Matthew Wilcox
2021-12-27 14:59 ` [PATCH v2 2/3] arm64: Support huge vmalloc mappings Kefeng Wang
2021-12-27 14:59 ` Kefeng Wang
2021-12-27 14:59 ` Kefeng Wang
2021-12-27 17:35 ` (No subject) William Kucharski
2021-12-27 17:35 ` William Kucharski
2021-12-27 17:35 ` William Kucharski
2021-12-28 1:36 ` Kefeng Wang
2021-12-28 1:36 ` Kefeng Wang
2021-12-28 1:36 ` Kefeng Wang
2022-01-15 10:05 ` [PATCH v2 2/3] arm64: Support huge vmalloc mappings Christophe Leroy
2022-01-15 10:05 ` Christophe Leroy
2022-01-15 10:05 ` Christophe Leroy
2021-12-27 14:59 ` [PATCH v2 3/3] x86: " Kefeng Wang
2021-12-27 14:59 ` Kefeng Wang
2021-12-27 14:59 ` Kefeng Wang
2021-12-27 15:56 ` Dave Hansen
2021-12-27 15:56 ` Dave Hansen
2021-12-27 15:56 ` Dave Hansen
2021-12-28 10:26 ` Kefeng Wang
2021-12-28 10:26 ` Kefeng Wang
2021-12-28 10:26 ` Kefeng Wang
2021-12-28 16:14 ` Dave Hansen
2021-12-28 16:14 ` Dave Hansen
2021-12-28 16:14 ` Dave Hansen
2021-12-29 11:01 ` Kefeng Wang
2021-12-29 11:01 ` Kefeng Wang
2021-12-29 11:01 ` Kefeng Wang
2022-01-15 10:17 ` Christophe Leroy
2022-01-15 10:17 ` Christophe Leroy
2022-01-15 10:17 ` Christophe Leroy
2022-01-15 10:15 ` Christophe Leroy
2022-01-15 10:15 ` Christophe Leroy
2022-01-15 10:15 ` Christophe Leroy
2022-01-18 2:46 ` Nicholas Piggin
2022-01-18 2:46 ` Nicholas Piggin
2022-01-18 2:46 ` Nicholas Piggin
2022-01-18 17:28 ` Dave Hansen
2022-01-18 17:28 ` Dave Hansen
2022-01-18 17:28 ` Dave Hansen
2022-01-19 4:17 ` Nicholas Piggin
2022-01-19 4:17 ` Nicholas Piggin
2022-01-19 4:17 ` Nicholas Piggin
2022-01-19 13:32 ` Kefeng Wang
2022-01-19 13:32 ` Kefeng Wang
2022-01-19 13:32 ` Kefeng Wang
2022-01-15 10:11 ` Christophe Leroy
2022-01-15 10:11 ` Christophe Leroy
2022-01-15 10:11 ` Christophe Leroy
2022-01-15 10:06 ` Christophe Leroy
2022-01-15 10:06 ` Christophe Leroy
2022-01-15 10:06 ` Christophe Leroy
2022-01-15 10:07 ` [PATCH v2 0/3] mm: support huge vmalloc mapping on arm64/x86 Christophe Leroy
2022-01-15 10:07 ` Christophe Leroy
2022-01-15 10:07 ` Christophe Leroy
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