| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <1bf29e9d-2e85-46ce-b8bf-d2ca5ec6bddd@arm.com>
Date: Tue, 29 Apr 2025 10:10:24 +0530
From: Dev Jain <dev.jain@....com>
To: Lance Yang <lance.yang@...ux.dev>, akpm@...ux-foundation.org
Cc: ryan.roberts@....com, david@...hat.com, willy@...radead.org,
linux-mm@...ck.org, linux-kernel@...r.kernel.org, catalin.marinas@....com,
will@...nel.org, Liam.Howlett@...cle.com, lorenzo.stoakes@...cle.com,
vbabka@...e.cz, jannh@...gle.com, anshuman.khandual@....com,
peterx@...hat.com, joey.gouly@....com, ioworker0@...il.com,
baohua@...nel.org, kevin.brodsky@....com, quic_zhenhuah@...cinc.com,
christophe.leroy@...roup.eu, yangyicong@...ilicon.com,
linux-arm-kernel@...ts.infradead.org, namit@...are.com, hughd@...gle.com,
yang@...amperecomputing.com, ziy@...dia.com
Subject: Re: [PATCH 0/7] Optimize mprotect for large folios
On 28/04/25 7:01 pm, Lance Yang wrote:
> I'm hitting the following compilation errors after applying this patch
> series:
Not sure why is that. I cherry-picked my commits onto
6ebffe676fcf8d259e3fb5d5fbf1a8227f22182c and the kernel builds for me.
Let me send a v2 rebased onto this.
>
> In file included from ./include/linux/kasan.h:37,
> from ./include/linux/slab.h:260,
> from ./include/linux/crypto.h:19,
> from arch/x86/kernel/asm-offsets.c:9:
> ./include/linux/pgtable.h: In function ‘modify_prot_start_ptes’:
> ./include/linux/pgtable.h:905:15: error: implicit declaration of
> function ‘ptep_modify_prot_start’ [-Werror=implicit-function-declaration]
> 905 | pte = ptep_modify_prot_start(vma, addr, ptep);
> | ^~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/pgtable.h:905:15: error: incompatible types when
> assigning to type ‘pte_t’ from type ‘int’
> ./include/linux/pgtable.h:909:27: error: incompatible types when
> assigning to type ‘pte_t’ from type ‘int’
> 909 | tmp_pte = ptep_modify_prot_start(vma, addr, ptep);
> | ^~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/pgtable.h: In function ‘modify_prot_commit_ptes’:
> ./include/linux/pgtable.h:925:17: error: implicit declaration of
> function ‘ptep_modify_prot_commit’ [-Werror=implicit-function-declaration]
> 925 | ptep_modify_prot_commit(vma, addr, ptep,
> old_pte, pte);
> | ^~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/pgtable.h: At top level:
> ./include/linux/pgtable.h:1360:21: error: conflicting types for
> ‘ptep_modify_prot_start’; have ‘pte_t(struct vm_area_struct *, long
> unsigned int, pte_t *)’
> 1360 | static inline pte_t ptep_modify_prot_start(struct
> vm_area_struct *vma,
> | ^~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/pgtable.h:905:15: note: previous implicit declaration of
> ‘ptep_modify_prot_start’ with type ‘int()’
> 905 | pte = ptep_modify_prot_start(vma, addr, ptep);
> | ^~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/pgtable.h:1371:20: warning: conflicting types for
> ‘ptep_modify_prot_commit’; have ‘void(struct vm_area_struct *, long
> unsigned int, pte_t *, pte_t, pte_t)’
> 1371 | static inline void ptep_modify_prot_commit(struct
> vm_area_struct *vma,
> | ^~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/pgtable.h:1371:20: error: static declaration of
> ‘ptep_modify_prot_commit’ follows non-static declaration
> ./include/linux/pgtable.h:925:17: note: previous implicit declaration of
> ‘ptep_modify_prot_commit’ with type ‘void(struct vm_area_struct *, long
> unsigned int, pte_t *, pte_t, pte_t)’
> 925 | ptep_modify_prot_commit(vma, addr, ptep,
> old_pte, pte);
> | ^~~~~~~~~~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
> make[2]: *** [scripts/Makefile.build:98: arch/x86/kernel/asm-offsets.s]
> Error 1
> make[1]: *** [/home/runner/work/mm-test-robot/mm-test-robot/linux/
> Makefile:1280: prepare0] Error 2
> make: *** [Makefile:248: __sub-make] Error 2
>
> Based on:
>
> mm-unstable b18dec6a6ad3d051dadc3c16fb838e4abddf8d3c ("mm/numa: remove
> unnecessary local variable in alloc_node_data()")
>
>
> Thanks,
> Lance
>
>
>
> On 2025/4/28 20:04, Dev Jain wrote:
>> This patchset optimizes the mprotect() system call for large folios
>> by PTE-batching.
>>
>> We use the following test cases to measure performance, mprotect()'ing
>> the mapped memory to read-only then read-write 40 times:
>>
>> Test case 1: Mapping 1G of memory, touching it to get PMD-THPs, then
>> pte-mapping those THPs
>> Test case 2: Mapping 1G of memory with 64K mTHPs
>> Test case 3: Mapping 1G of memory with 4K pages
>>
>> Average execution time on arm64, Apple M3:
>> Before the patchset:
>> T1: 7.9 seconds T2: 7.9 seconds T3: 4.2 seconds
>>
>> After the patchset:
>> T1: 2.1 seconds T2: 2.2 seconds T3: 4.2 seconds
>>
>> Observing T1/T2 and T3 before the patchset, we also remove the regression
>> introduced by ptep_get() on a contpte block. And, for large folios we get
>> an almost 276% performance improvement.
>>
>> Dev Jain (7):
>> mm: Refactor code in mprotect
>> mm: Optimize mprotect() by batch-skipping PTEs
>> mm: Add batched versions of ptep_modify_prot_start/commit
>> arm64: Add batched version of ptep_modify_prot_start
>> arm64: Add batched version of ptep_modify_prot_commit
>> mm: Batch around can_change_pte_writable()
>> mm: Optimize mprotect() through PTE-batching
>>
>> arch/arm64/include/asm/pgtable.h | 10 ++
>> arch/arm64/mm/mmu.c | 21 +++-
>> include/linux/mm.h | 4 +-
>> include/linux/pgtable.h | 42 ++++++++
>> mm/gup.c | 2 +-
>> mm/huge_memory.c | 4 +-
>> mm/memory.c | 6 +-
>> mm/mprotect.c | 163 +++++++++++++++++++++----------
>> mm/pgtable-generic.c | 16 ++-
>> 9 files changed, 198 insertions(+), 70 deletions(-)
>>
>
>
Powered by blists - more mailing lists