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| author | Andi Kleen <ak@suse.de> | 2006-03-25 16:29:37 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-25 09:10:53 -0800 |
| commit | 85f9eebccde51e24896f31383f5b70776362e1a6 (patch) | |
| tree | de990ac5c7982fb05940d764b58f4ea20013c77d /arch/x86_64/kernel | |
| parent | 77d910f557c44db0fa72ee856c41cdd56972cfca (diff) | |
| download | blackbird-op-linux-85f9eebccde51e24896f31383f5b70776362e1a6.tar.gz blackbird-op-linux-85f9eebccde51e24896f31383f5b70776362e1a6.zip | |
[PATCH] x86_64: Use cpu_relax in poll loop in GART IOMMU
The code waits for the GART to clear the TLB flush bit. Use cpu_relax
in this time to allow hypervisors to yield the CPU in this time.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64/kernel')
| -rw-r--r-- | arch/x86_64/kernel/pci-gart.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86_64/kernel/pci-gart.c b/arch/x86_64/kernel/pci-gart.c index 0c3f052ba6ce..ebd125e968be 100644 --- a/arch/x86_64/kernel/pci-gart.c +++ b/arch/x86_64/kernel/pci-gart.c @@ -148,9 +148,12 @@ static void flush_gart(struct device *dev) if (!northbridges[i]) continue; /* Make sure the hardware actually executed the flush. */ - do { + for (;;) { pci_read_config_dword(northbridges[i], 0x9c, &w); - } while (w & 1); + if (!(w & 1)) + break; + cpu_relax(); + } } if (!flushed) printk("nothing to flush?\n"); |
