[patch 1/5] avoid tlb gather restarts.

Martin Schwidefsky
2007-06-29T14:14:15Z

[-- Attachment #1: 002-flush-restarts.diff --]
[-- Type: text/plain, Size: 1309 bytes --]

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

If need_resched() is false it is unnecessary to call tlb_finish_mmu()
and tlb_gather_mmu() for each vma in unmap_vmas(). Moving the tlb gather
restart under the if that contains the cond_resched() will avoid
unnecessary tlb flush operations that are triggered by tlb_finish_mmu()
and tlb_gather_mmu().

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

mm/memory.c | 7 +++----
1 files changed, 3 insertions(+), 4 deletions(-)

diff -urpN linux-2.6/mm/memory.c linux-2.6-patched/mm/memory.c
--- linux-2.6/mm/memory.c 2007-06-29 15:44:08.000000000 +0200
+++ linux-2.6-patched/mm/memory.c 2007-06-29 15:44:08.000000000 +0200
@@ -851,19 +851,18 @@ unsigned long unmap_vmas(struct mmu_gath
break;
}

- tlb_finish_mmu(*tlbp, tlb_start, start);
-
if (need_resched() ||
(i_mmap_lock && need_lockbreak(i_mmap_lock))) {
+ tlb_finish_mmu(*tlbp, tlb_start, start);
if (i_mmap_lock) {
*tlbp = NULL;
goto out;
}
cond_resched();
+ *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
+ tlb_start_valid = 0;
}

- *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
- tlb_start_valid = 0;
zap_work = ZAP_BLOCK_SIZE;
}
}