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authorWill Deacon <will.deacon@arm.com>2014-10-29 10:03:09 +0000
committerWill Deacon <will.deacon@arm.com>2014-11-17 10:12:42 +0000
commitfb7332a9fedfd62b1ba6530c86f39f0fa38afd49 (patch)
tree5e77bd4944da750634c4438df64257cdeaa58888 /mm/memory.c
parent63648dd20fa0780ab6c1e923b5c276d257422cb3 (diff)
downloadop-kernel-dev-fb7332a9fedfd62b1ba6530c86f39f0fa38afd49.zip
op-kernel-dev-fb7332a9fedfd62b1ba6530c86f39f0fa38afd49.tar.gz
mmu_gather: move minimal range calculations into generic code
On architectures with hardware broadcasting of TLB invalidation messages , it makes sense to reduce the range of the mmu_gather structure when unmapping page ranges based on the dirty address information passed to tlb_remove_tlb_entry. arm64 already does this by directly manipulating the start/end fields of the gather structure, but this confuses the generic code which does not expect these fields to change and can end up calculating invalid, negative ranges when forcing a flush in zap_pte_range. This patch moves the minimal range calculation out of the arm64 code and into the generic implementation, simplifying zap_pte_range in the process (which no longer needs to care about start/end, since they will point to the appropriate ranges already). With the range being tracked by core code, the need_flush flag is dropped in favour of checking that the end of the range has actually been set. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Michal Simek <monstr@monstr.eu> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c30
1 files changed, 8 insertions, 22 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 1cc6bfb..c71edae 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -220,9 +220,6 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long
/* Is it from 0 to ~0? */
tlb->fullmm = !(start | (end+1));
tlb->need_flush_all = 0;
- tlb->start = start;
- tlb->end = end;
- tlb->need_flush = 0;
tlb->local.next = NULL;
tlb->local.nr = 0;
tlb->local.max = ARRAY_SIZE(tlb->__pages);
@@ -232,15 +229,20 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb->batch = NULL;
#endif
+
+ __tlb_reset_range(tlb);
}
static void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
{
- tlb->need_flush = 0;
+ if (!tlb->end)
+ return;
+
tlb_flush(tlb);
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb_table_flush(tlb);
#endif
+ __tlb_reset_range(tlb);
}
static void tlb_flush_mmu_free(struct mmu_gather *tlb)
@@ -256,8 +258,6 @@ static void tlb_flush_mmu_free(struct mmu_gather *tlb)
void tlb_flush_mmu(struct mmu_gather *tlb)
{
- if (!tlb->need_flush)
- return;
tlb_flush_mmu_tlbonly(tlb);
tlb_flush_mmu_free(tlb);
}
@@ -292,7 +292,7 @@ int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
struct mmu_gather_batch *batch;
- VM_BUG_ON(!tlb->need_flush);
+ VM_BUG_ON(!tlb->end);
batch = tlb->active;
batch->pages[batch->nr++] = page;
@@ -359,8 +359,6 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
{
struct mmu_table_batch **batch = &tlb->batch;
- tlb->need_flush = 1;
-
/*
* When there's less then two users of this mm there cannot be a
* concurrent page-table walk.
@@ -1185,20 +1183,8 @@ again:
arch_leave_lazy_mmu_mode();
/* Do the actual TLB flush before dropping ptl */
- if (force_flush) {
- unsigned long old_end;
-
- /*
- * Flush the TLB just for the previous segment,
- * then update the range to be the remaining
- * TLB range.
- */
- old_end = tlb->end;
- tlb->end = addr;
+ if (force_flush)
tlb_flush_mmu_tlbonly(tlb);
- tlb->start = addr;
- tlb->end = old_end;
- }
pte_unmap_unlock(start_pte, ptl);
/*
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