From: Vlastimil Babka <vbabka@suse.cz>
To: Charlie Jenkins <charlie@rivosinc.com>,
Arnd Bergmann <arnd@arndb.de>,
Richard Henderson <richard.henderson@linaro.org>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
Vineet Gupta <vgupta@kernel.org>,
Russell King <linux@armlinux.org.uk>, Guo Ren <guoren@kernel.org>,
Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Helge Deller <deller@gmx.de>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Naveen N Rao <naveen@kernel.org>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
"David S. Miller" <davem@davemloft.net>,
Andreas Larsson <andreas@gaisler.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Muchun Song <muchun.song@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Shuah Khan <shuah@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org,
linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
loongarch@lists.linux.dev, linux-mips@vger.kernel.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org, linux-mm@kvack.org,
linux-kselftest@vger.kernel.org,
Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH RFC v2 0/4] mm: Introduce MAP_BELOW_HINT
Date: Thu, 29 Aug 2024 11:02:34 +0200 [thread overview]
Message-ID: <a048515e-f6e4-4d77-920b-6742529f3ca4@suse.cz> (raw)
In-Reply-To: <20240829-patches-below_hint_mmap-v2-0-638a28d9eae0@rivosinc.com>
Such a large recipient list and no linux-api. CC'd, please include it on
future postings.
On 8/29/24 09:15, Charlie Jenkins wrote:
> Some applications rely on placing data in free bits addresses allocated
> by mmap. Various architectures (eg. x86, arm64, powerpc) restrict the
> address returned by mmap to be less than the 48-bit address space,
> unless the hint address uses more than 47 bits (the 48th bit is reserved
> for the kernel address space).
>
> The riscv architecture needs a way to similarly restrict the virtual
> address space. On the riscv port of OpenJDK an error is thrown if
> attempted to run on the 57-bit address space, called sv57 [1]. golang
> has a comment that sv57 support is not complete, but there are some
> workarounds to get it to mostly work [2].
>
> These applications work on x86 because x86 does an implicit 47-bit
> restriction of mmap() address that contain a hint address that is less
> than 48 bits.
>
> Instead of implicitly restricting the address space on riscv (or any
> current/future architecture), a flag would allow users to opt-in to this
> behavior rather than opt-out as is done on other architectures. This is
> desirable because it is a small class of applications that do pointer
> masking.
I doubt it's desirable to have different behavior depending on architecture.
Also you could say it's a small class of applications that need more than 47
bits.
> This flag will also allow seemless compatibility between all
> architectures, so applications like Go and OpenJDK that use bits in a
> virtual address can request the exact number of bits they need in a
> generic way. The flag can be checked inside of vm_unmapped_area() so
> that this flag does not have to be handled individually by each
> architecture.
>
> Link:
> https://github.com/openjdk/jdk/blob/f080b4bb8a75284db1b6037f8c00ef3b1ef1add1/src/hotspot/cpu/riscv/vm_version_riscv.cpp#L79
> [1]
> Link:
> https://github.com/golang/go/blob/9e8ea567c838574a0f14538c0bbbd83c3215aa55/src/runtime/tagptr_64bit.go#L47
> [2]
>
> To: Arnd Bergmann <arnd@arndb.de>
> To: Richard Henderson <richard.henderson@linaro.org>
> To: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
> To: Matt Turner <mattst88@gmail.com>
> To: Vineet Gupta <vgupta@kernel.org>
> To: Russell King <linux@armlinux.org.uk>
> To: Guo Ren <guoren@kernel.org>
> To: Huacai Chen <chenhuacai@kernel.org>
> To: WANG Xuerui <kernel@xen0n.name>
> To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> To: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
> To: Helge Deller <deller@gmx.de>
> To: Michael Ellerman <mpe@ellerman.id.au>
> To: Nicholas Piggin <npiggin@gmail.com>
> To: Christophe Leroy <christophe.leroy@csgroup.eu>
> To: Naveen N Rao <naveen@kernel.org>
> To: Alexander Gordeev <agordeev@linux.ibm.com>
> To: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
> To: Heiko Carstens <hca@linux.ibm.com>
> To: Vasily Gorbik <gor@linux.ibm.com>
> To: Christian Borntraeger <borntraeger@linux.ibm.com>
> To: Sven Schnelle <svens@linux.ibm.com>
> To: Yoshinori Sato <ysato@users.sourceforge.jp>
> To: Rich Felker <dalias@libc.org>
> To: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> To: David S. Miller <davem@davemloft.net>
> To: Andreas Larsson <andreas@gaisler.com>
> To: Thomas Gleixner <tglx@linutronix.de>
> To: Ingo Molnar <mingo@redhat.com>
> To: Borislav Petkov <bp@alien8.de>
> To: Dave Hansen <dave.hansen@linux.intel.com>
> To: x86@kernel.org
> To: H. Peter Anvin <hpa@zytor.com>
> To: Andy Lutomirski <luto@kernel.org>
> To: Peter Zijlstra <peterz@infradead.org>
> To: Muchun Song <muchun.song@linux.dev>
> To: Andrew Morton <akpm@linux-foundation.org>
> To: Liam R. Howlett <Liam.Howlett@oracle.com>
> To: Vlastimil Babka <vbabka@suse.cz>
> To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> To: Shuah Khan <shuah@kernel.org>
> Cc: linux-arch@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-alpha@vger.kernel.org
> Cc: linux-snps-arc@lists.infradead.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-csky@vger.kernel.org
> Cc: loongarch@lists.linux.dev
> Cc: linux-mips@vger.kernel.org
> Cc: linux-parisc@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-s390@vger.kernel.org
> Cc: linux-sh@vger.kernel.org
> Cc: sparclinux@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: linux-kselftest@vger.kernel.org
> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
>
> Changes in v2:
> - Added much greater detail to cover letter
> - Removed all code that touched architecture specific code and was able
> to factor this out into all generic functions, except for flags that
> needed to be added to vm_unmapped_area_info
> - Made this an RFC since I have only tested it on riscv and x86
> - Link to v1: https://lore.kernel.org/r/20240827-patches-below_hint_mmap-v1-0-46ff2eb9022d@rivosinc.com
>
> ---
> Charlie Jenkins (4):
> mm: Add MAP_BELOW_HINT
> mm: Add hint and mmap_flags to struct vm_unmapped_area_info
> mm: Support MAP_BELOW_HINT in vm_unmapped_area()
> selftests/mm: Create MAP_BELOW_HINT test
>
> arch/alpha/kernel/osf_sys.c | 2 ++
> arch/arc/mm/mmap.c | 3 +++
> arch/arm/mm/mmap.c | 7 ++++++
> arch/csky/abiv1/mmap.c | 3 +++
> arch/loongarch/mm/mmap.c | 3 +++
> arch/mips/mm/mmap.c | 3 +++
> arch/parisc/kernel/sys_parisc.c | 3 +++
> arch/powerpc/mm/book3s64/slice.c | 7 ++++++
> arch/s390/mm/hugetlbpage.c | 4 ++++
> arch/s390/mm/mmap.c | 6 ++++++
> arch/sh/mm/mmap.c | 6 ++++++
> arch/sparc/kernel/sys_sparc_32.c | 3 +++
> arch/sparc/kernel/sys_sparc_64.c | 6 ++++++
> arch/sparc/mm/hugetlbpage.c | 4 ++++
> arch/x86/kernel/sys_x86_64.c | 6 ++++++
> arch/x86/mm/hugetlbpage.c | 4 ++++
> fs/hugetlbfs/inode.c | 4 ++++
> include/linux/mm.h | 2 ++
> include/uapi/asm-generic/mman-common.h | 1 +
> mm/mmap.c | 9 ++++++++
> tools/include/uapi/asm-generic/mman-common.h | 1 +
> tools/testing/selftests/mm/Makefile | 1 +
> tools/testing/selftests/mm/map_below_hint.c | 32 ++++++++++++++++++++++++++++
> 23 files changed, 120 insertions(+)
> ---
> base-commit: 5be63fc19fcaa4c236b307420483578a56986a37
> change-id: 20240827-patches-below_hint_mmap-b13d79ae1c55
next prev parent reply other threads:[~2024-08-29 9:02 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-29 7:15 [PATCH RFC v2 0/4] mm: Introduce MAP_BELOW_HINT Charlie Jenkins
2024-08-29 7:15 ` [PATCH RFC v2 1/4] mm: Add MAP_BELOW_HINT Charlie Jenkins
2024-08-29 8:26 ` Michael Ellerman
2024-08-30 1:16 ` Charlie Jenkins
2024-08-29 7:15 ` [PATCH RFC v2 2/4] mm: Add hint and mmap_flags to struct vm_unmapped_area_info Charlie Jenkins
2024-08-29 8:48 ` Lorenzo Stoakes
2024-08-30 1:11 ` Charlie Jenkins
2024-09-03 17:18 ` Christophe Leroy
2024-08-29 7:16 ` [PATCH RFC v2 3/4] mm: Support MAP_BELOW_HINT in vm_unmapped_area() Charlie Jenkins
2024-08-29 7:16 ` [PATCH RFC v2 4/4] selftests/mm: Create MAP_BELOW_HINT test Charlie Jenkins
2024-08-29 8:30 ` [PATCH RFC v2 0/4] mm: Introduce MAP_BELOW_HINT Michal Hocko
2024-08-29 17:33 ` Charlie Jenkins
2024-09-03 8:44 ` Michal Hocko
2024-08-29 8:42 ` Lorenzo Stoakes
2024-08-29 9:54 ` Lorenzo Stoakes
2024-08-29 22:16 ` Charlie Jenkins
2024-08-30 9:52 ` Lorenzo Stoakes
2024-08-31 1:45 ` Charlie Jenkins
2024-08-30 15:03 ` Dave Hansen
2024-08-30 15:18 ` Lorenzo Stoakes
2024-08-29 9:02 ` Vlastimil Babka [this message]
2024-08-29 17:00 ` Palmer Dabbelt
2024-09-05 6:47 ` Kirill A. Shutemov
2024-09-05 17:26 ` Charlie Jenkins
2024-09-09 9:46 ` Kirill A. Shutemov
2024-10-21 13:22 ` Steven Price
2024-10-21 19:48 ` Liam R. Howlett
2024-10-23 9:31 ` Steven Price
2024-10-23 18:10 ` Liam R. Howlett
2024-10-24 10:52 ` Steven Price
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=a048515e-f6e4-4d77-920b-6742529f3ca4@suse.cz \
--to=vbabka@suse.cz \
--cc=James.Bottomley@HansenPartnership.com \
--cc=Liam.Howlett@oracle.com \
--cc=agordeev@linux.ibm.com \
--cc=akpm@linux-foundation.org \
--cc=andreas@gaisler.com \
--cc=arnd@arndb.de \
--cc=borntraeger@linux.ibm.com \
--cc=bp@alien8.de \
--cc=charlie@rivosinc.com \
--cc=chenhuacai@kernel.org \
--cc=christophe.leroy@csgroup.eu \
--cc=dalias@libc.org \
--cc=dave.hansen@linux.intel.com \
--cc=davem@davemloft.net \
--cc=deller@gmx.de \
--cc=gerald.schaefer@linux.ibm.com \
--cc=glaubitz@physik.fu-berlin.de \
--cc=gor@linux.ibm.com \
--cc=guoren@kernel.org \
--cc=hca@linux.ibm.com \
--cc=hpa@zytor.com \
--cc=ink@jurassic.park.msu.ru \
--cc=kernel@xen0n.name \
--cc=linux-alpha@vger.kernel.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-csky@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-parisc@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-sh@vger.kernel.org \
--cc=linux-snps-arc@lists.infradead.org \
--cc=linux@armlinux.org.uk \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=loongarch@lists.linux.dev \
--cc=lorenzo.stoakes@oracle.com \
--cc=luto@kernel.org \
--cc=mattst88@gmail.com \
--cc=mingo@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=muchun.song@linux.dev \
--cc=naveen@kernel.org \
--cc=npiggin@gmail.com \
--cc=peterz@infradead.org \
--cc=richard.henderson@linaro.org \
--cc=shuah@kernel.org \
--cc=sparclinux@vger.kernel.org \
--cc=svens@linux.ibm.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=tsbogend@alpha.franken.de \
--cc=vgupta@kernel.org \
--cc=x86@kernel.org \
--cc=ysato@users.sourceforge.jp \
/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: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).