diff options
| author | Kefeng Wang <wangkefeng.wang@huawei.com> | 2024-04-03 16:37:59 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-04-25 20:56:38 -0700 |
| commit | 6ea02ee489799317c6640ac014c49b1d1b7124c5 (patch) | |
| tree | b372790fba7541e3ab35ff4de6c24ac2882b3d18 /arch | |
| parent | 3931b871c4936c00c4e27c469056d8da47a3493f (diff) | |
arm64: mm: cleanup __do_page_fault()
Patch series "arch/mm/fault: accelerate pagefault when badaccess", v2.
After VMA lock-based page fault handling enabled, if bad access met
under per-vma lock, it will fallback to mmap_lock-based handling,
so it leads to unnessary mmap lock and vma find again. A test from
lmbench shows 34% improve after this changes on arm64,
lat_sig -P 1 prot lat_sig 0.29194 -> 0.19198
This patch (of 7):
The __do_page_fault() only calls handle_mm_fault() after vm_flags checked,
and it is only called by do_page_fault(), let's squash it into
do_page_fault() to cleanup code.
Link: https://lkml.kernel.org/r/20240403083805.1818160-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240403083805.1818160-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/mm/fault.c | 27 |
1 files changed, 7 insertions, 20 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 8251e2fea9c7..9bb9f395351a 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -486,25 +486,6 @@ static void do_bad_area(unsigned long far, unsigned long esr, } } -#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000) -#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000) - -static vm_fault_t __do_page_fault(struct mm_struct *mm, - struct vm_area_struct *vma, unsigned long addr, - unsigned int mm_flags, unsigned long vm_flags, - struct pt_regs *regs) -{ - /* - * Ok, we have a good vm_area for this memory access, so we can handle - * it. - * Check that the permissions on the VMA allow for the fault which - * occurred. - */ - if (!(vma->vm_flags & vm_flags)) - return VM_FAULT_BADACCESS; - return handle_mm_fault(vma, addr, mm_flags, regs); -} - static bool is_el0_instruction_abort(unsigned long esr) { return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW; @@ -519,6 +500,9 @@ static bool is_write_abort(unsigned long esr) return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM); } +#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000) +#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000) + static int __kprobes do_page_fault(unsigned long far, unsigned long esr, struct pt_regs *regs) { @@ -617,7 +601,10 @@ retry: goto done; } - fault = __do_page_fault(mm, vma, addr, mm_flags, vm_flags, regs); + if (!(vma->vm_flags & vm_flags)) + fault = VM_FAULT_BADACCESS; + else + fault = handle_mm_fault(vma, addr, mm_flags, regs); /* Quick path to respond to signals */ if (fault_signal_pending(fault, regs)) { |