Commit 4ce6bea2 authored by Kautuk Consul's avatar Kautuk Consul Committed by Chris Metcalf

tile/mm/fault.c: Port OOM changes to handle_page_fault

Commit d065bd81
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e05
(x86,mm: make pagefault killable)

The above commits introduced changes into the x86 pagefault handler
for making the page fault handler retryable as well as killable.

These changes reduce the mmap_sem hold time, which is crucial
during OOM killer invocation.

Port these changes to tile.
Signed-off-by: default avatarKautuk Consul <consul.kautuk@gmail.com>
[cmetcalf@tilera.com: initialize "flags" after "write" updated.]
Signed-off-by: default avatarChris Metcalf <cmetcalf@tilera.com>
parent c6f696f6
...@@ -273,11 +273,15 @@ static int handle_page_fault(struct pt_regs *regs, ...@@ -273,11 +273,15 @@ static int handle_page_fault(struct pt_regs *regs,
int si_code; int si_code;
int is_kernel_mode; int is_kernel_mode;
pgd_t *pgd; pgd_t *pgd;
unsigned int flags;
/* on TILE, protection faults are always writes */ /* on TILE, protection faults are always writes */
if (!is_page_fault) if (!is_page_fault)
write = 1; write = 1;
flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
(write ? FAULT_FLAG_WRITE : 0));
is_kernel_mode = (EX1_PL(regs->ex1) != USER_PL); is_kernel_mode = (EX1_PL(regs->ex1) != USER_PL);
tsk = validate_current(); tsk = validate_current();
...@@ -382,6 +386,8 @@ static int handle_page_fault(struct pt_regs *regs, ...@@ -382,6 +386,8 @@ static int handle_page_fault(struct pt_regs *regs,
vma = NULL; /* happy compiler */ vma = NULL; /* happy compiler */
goto bad_area_nosemaphore; goto bad_area_nosemaphore;
} }
retry:
down_read(&mm->mmap_sem); down_read(&mm->mmap_sem);
} }
...@@ -429,7 +435,11 @@ static int handle_page_fault(struct pt_regs *regs, ...@@ -429,7 +435,11 @@ static int handle_page_fault(struct pt_regs *regs,
* make sure we exit gracefully rather than endlessly redo * make sure we exit gracefully rather than endlessly redo
* the fault. * the fault.
*/ */
fault = handle_mm_fault(mm, vma, address, write); fault = handle_mm_fault(mm, vma, address, flags);
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
return 0;
if (unlikely(fault & VM_FAULT_ERROR)) { if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM) if (fault & VM_FAULT_OOM)
goto out_of_memory; goto out_of_memory;
...@@ -437,10 +447,22 @@ static int handle_page_fault(struct pt_regs *regs, ...@@ -437,10 +447,22 @@ static int handle_page_fault(struct pt_regs *regs,
goto do_sigbus; goto do_sigbus;
BUG(); BUG();
} }
if (fault & VM_FAULT_MAJOR) if (flags & FAULT_FLAG_ALLOW_RETRY) {
tsk->maj_flt++; if (fault & VM_FAULT_MAJOR)
else tsk->maj_flt++;
tsk->min_flt++; else
tsk->min_flt++;
if (fault & VM_FAULT_RETRY) {
flags &= ~FAULT_FLAG_ALLOW_RETRY;
/*
* No need to up_read(&mm->mmap_sem) as we would
* have already released it in __lock_page_or_retry
* in mm/filemap.c.
*/
goto retry;
}
}
#if CHIP_HAS_TILE_DMA() || CHIP_HAS_SN_PROC() #if CHIP_HAS_TILE_DMA() || CHIP_HAS_SN_PROC()
/* /*
......
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