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s390/mm: try VMA lock-based page fault handling first

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Attempt VMA lock-based page fault handling first, and fall back to the
existing mmap_lock-based handling if that fails.

This is the s390 variant of "x86/mm: try VMA lock-based page fault handling
first".

Link: https://lkml.kernel.org/r/20230314132808.1266335-1-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Heiko Carstens 2023-03-14 14:28:08 +01:00 • committed by Andrew Morton
parent c7f8f31c00
commit e06f47a165
2 changed files with 25 additions and 0 deletions
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1
arch/s390/Kconfig
View file

@ -120,6 +120,7 @@ config S390
select ARCH_SUPPORTS_DEBUG_PAGEALLOC select ARCH_SUPPORTS_DEBUG_PAGEALLOC
select ARCH_SUPPORTS_HUGETLBFS select ARCH_SUPPORTS_HUGETLBFS
select ARCH_SUPPORTS_NUMA_BALANCING select ARCH_SUPPORTS_NUMA_BALANCING
select ARCH_SUPPORTS_PER_VMA_LOCK
select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_WANTS_DYNAMIC_TASK_STRUCT select ARCH_WANTS_DYNAMIC_TASK_STRUCT

24
arch/s390/mm/fault.c
View file

@ -407,6 +407,30 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access)
access = VM_WRITE; access = VM_WRITE;
if (access == VM_WRITE) if (access == VM_WRITE)
flags |= FAULT_FLAG_WRITE; flags |= FAULT_FLAG_WRITE;
#ifdef CONFIG_PER_VMA_LOCK
if (!(flags & FAULT_FLAG_USER))
goto lock_mmap;
vma = lock_vma_under_rcu(mm, address);
if (!vma)
goto lock_mmap;
if (!(vma->vm_flags & access)) {
vma_end_read(vma);
goto lock_mmap;
}
fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs);
vma_end_read(vma);
if (!(fault & VM_FAULT_RETRY)) {
count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
goto out;
}
count_vm_vma_lock_event(VMA_LOCK_RETRY);
/* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) {
fault = VM_FAULT_SIGNAL;
goto out;
}
lock_mmap:
#endif /* CONFIG_PER_VMA_LOCK */
mmap_read_lock(mm); mmap_read_lock(mm);
gmap = NULL; gmap = NULL;