lkml.org 
[lkml]   [2008]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH] x86: avoid unnecessary low zone allocation in AMD IOMMU's alloc_coherent
From
This is for tip/iommu.

btw, Joery, what happens if map_sg (or map_single) gets
not-DMA-capable buffer in the case of !iommu || !domain?


==
From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Subject: [PATCH] x86: avoid unnecessary low zone allocation in AMD IOMMU's alloc_coherent

x86's common alloc_coherent (dma_alloc_coherent in dma-mapping.h) sets
up the gfp flag according to the device dma_mask but AMD IOMMU doesn't
need it for devices that the IOMMU can do virtual mappings for. This
patch avoids unnecessary low zone allocation.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
---
arch/x86/kernel/amd_iommu.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 01c68c3..8efd249 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -999,6 +999,11 @@ static void *alloc_coherent(struct device *dev, size_t size,
u16 devid;
phys_addr_t paddr;

+ get_device_resources(dev, &iommu, &domain, &devid);
+
+ if (iommu && domain)
+ flag &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
+
virt_addr = (void *)__get_free_pages(flag, get_order(size));
if (!virt_addr)
return 0;
@@ -1006,8 +1011,6 @@ static void *alloc_coherent(struct device *dev, size_t size,
memset(virt_addr, 0, size);
paddr = virt_to_phys(virt_addr);

- get_device_resources(dev, &iommu, &domain, &devid);
-
if (!iommu || !domain) {
*dma_addr = (dma_addr_t)paddr;
return virt_addr;
--
1.5.4.2


\
 
 \ /
  Last update: 2008-09-10 13:23    [W:0.794 / U:0.608 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site