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authorNishanth Aravamudan <nacc@linux.vnet.ibm.com>2013-10-01 14:04:53 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-10-13 16:08:31 -0700
commite98d86aaa251cbd7c9745a3743ec4fa0c7c54c25 (patch)
tree54352986c0f6b1c5580eccc445904f09fd49b7af /arch/powerpc
parent7a7e86e4ef76e20e0e945c8216bbb0afa695d8ab (diff)
downloadlinaro-lsk-e98d86aaa251cbd7c9745a3743ec4fa0c7c54c25.tar.gz
powerpc/iommu: Use GFP_KERNEL instead of GFP_ATOMIC in iommu_init_table()
commit 1cf389df090194a0976dc867b7fffe99d9d490cb upstream. Under heavy (DLPAR?) stress, we tripped this panic() in arch/powerpc/kernel/iommu.c::iommu_init_table(): page = alloc_pages_node(nid, GFP_ATOMIC, get_order(sz)); if (!page) panic("iommu_init_table: Can't allocate %ld bytes\n", sz); Before the panic() we got a page allocation failure for an order-2 allocation. There appears to be memory free, but perhaps not in the ATOMIC context. I looked through all the call-sites of iommu_init_table() and didn't see any obvious reason to need an ATOMIC allocation. Most call-sites in fact have an explicit GFP_KERNEL allocation shortly before the call to iommu_init_table(), indicating we are not in an atomic context. There is some indirection for some paths, but I didn't see any locks indicating that GFP_KERNEL is inappropriate. With this change under the same conditions, we have not been able to reproduce the panic. Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/iommu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index c0d0dbddfba..93d8d96840b 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -658,7 +658,7 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
/* number of bytes needed for the bitmap */
sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
- page = alloc_pages_node(nid, GFP_ATOMIC, get_order(sz));
+ page = alloc_pages_node(nid, GFP_KERNEL, get_order(sz));
if (!page)
panic("iommu_init_table: Can't allocate %ld bytes\n", sz);
tbl->it_map = page_address(page);