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authorHugh Dickins <hugh@veritas.com>2005-10-29 21:15:53 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-30 00:40:36 -0400
commite040f218bb49a6965a5b77edce05fe47a62dda39 (patch)
treee5547e04fa312f1b87db66e4ac2b6eed885ca276 /mm/memory.c
parent09ad4bbc3a5c93316d7f4ffc0c310d9cbb28c2f0 (diff)
[PATCH] mm: copy_pte_range progress fix
My latency breaking in copy_pte_range didn't work as intended: instead of checking at regularish intervals, after the first interval it checked every time around the loop, too impatient to be preempted. Fix that. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 1db40e935e55..222c13e46130 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -410,7 +410,7 @@ static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
410{ 410{
411 pte_t *src_pte, *dst_pte; 411 pte_t *src_pte, *dst_pte;
412 unsigned long vm_flags = vma->vm_flags; 412 unsigned long vm_flags = vma->vm_flags;
413 int progress; 413 int progress = 0;
414 414
415again: 415again:
416 dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr); 416 dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr);
@@ -418,17 +418,19 @@ again:
418 return -ENOMEM; 418 return -ENOMEM;
419 src_pte = pte_offset_map_nested(src_pmd, addr); 419 src_pte = pte_offset_map_nested(src_pmd, addr);
420 420
421 progress = 0;
422 spin_lock(&src_mm->page_table_lock); 421 spin_lock(&src_mm->page_table_lock);
423 do { 422 do {
424 /* 423 /*
425 * We are holding two locks at this point - either of them 424 * We are holding two locks at this point - either of them
426 * could generate latencies in another task on another CPU. 425 * could generate latencies in another task on another CPU.
427 */ 426 */
428 if (progress >= 32 && (need_resched() || 427 if (progress >= 32) {
429 need_lockbreak(&src_mm->page_table_lock) || 428 progress = 0;
430 need_lockbreak(&dst_mm->page_table_lock))) 429 if (need_resched() ||
431 break; 430 need_lockbreak(&src_mm->page_table_lock) ||
431 need_lockbreak(&dst_mm->page_table_lock))
432 break;
433 }
432 if (pte_none(*src_pte)) { 434 if (pte_none(*src_pte)) {
433 progress++; 435 progress++;
434 continue; 436 continue;