diff options
| author | Hugh Dickins <hugh@veritas.com> | 2005-01-07 21:58:19 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@evo.osdl.org> | 2005-01-07 21:58:19 -0800 |
| commit | 84c496cfadc2c9471340a9ccdf7f82be6f627a5b (patch) | |
| tree | 9650eea738d0448c9025ff4ed814de7a0222ade9 /mm | |
| parent | b37e39b03bcd49397cac7b937d9b180157705e08 (diff) | |
| download | history-84c496cfadc2c9471340a9ccdf7f82be6f627a5b.tar.gz | |
[PATCH] vmtrunc: restore unmap_vmas zap_bytes
The low-latency unmap_vmas patch silently moved the zap_bytes test after the
TLB finish and lockbreak and regather: why? That not only makes zap_bytes
redundant (might as well use ZAP_BLOCK_SIZE), it makes the unmap_vmas level
redundant too - it's all about saving TLB flushes when unmapping a series of
small vmas.
Move zap_bytes test back before the lockbreak, and delete the curious comment
that a small zap block size doesn't matter: it's true need_flush prevents TLB
flush when no page has been unmapped, but unmapping pages in small blocks
involves many more TLB flushes than in large blocks.
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')
| -rw-r--r-- | mm/memory.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/mm/memory.c b/mm/memory.c index 5c6a4db990acfa..cb073d049868c5 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -613,10 +613,6 @@ static void unmap_page_range(struct mmu_gather *tlb, } #ifdef CONFIG_PREEMPT -/* - * It's not an issue to have a small zap block size - TLB flushes - * only happen once normally, due to the tlb->need_flush optimization. - */ # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) #else /* No preempt: go for improved straight-line efficiency */ @@ -695,6 +691,9 @@ int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm, start += block; zap_bytes -= block; + if ((long)zap_bytes > 0) + continue; + if (!atomic) { int fullmm = tlb_is_full_mm(*tlbp); tlb_finish_mmu(*tlbp, tlb_start, start); @@ -702,8 +701,6 @@ int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm, *tlbp = tlb_gather_mmu(mm, fullmm); tlb_start_valid = 0; } - if ((long)zap_bytes > 0) - continue; zap_bytes = ZAP_BLOCK_SIZE; } } |