On 03/05/2015 12:53 AM, David Rientjes wrote:
On Wed, 4 Mar 2015, Kazutomo Yoshii wrote:
I noticed that numa_alloc_onnode() failed to allocate memory on a
specified node in v4.0-rc1. I added a code to check the return value
of walk_page_range() in queue_pages_range() so that do_mbind() only
returns an error number or zero.
I assume this is libnuma-2.0.10?
I used libnuma-2.0.9. Here is a strace output related to
numa_alloc_onnode()
mmap(NULL, 4194304, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0) =
0x7fe9b8334000
mbind(0x7fe9b8334000, 4194304, MPOL_BIND, 0x1b43bf0, 1025, 0) = 1
I believe mbind() returning a positive number is just a wrong behavior.
A tricky part is that libnuma only checks a negative error,
so numa_alloc_onnode() itself didn't fail. I noticed this first when I
was checking
memory placement using the proc pagemap.
Signed-off-by: Kazutomo Yoshii <kazutomo.yos...@gmail.com>
---
mm/mempolicy.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4721046..ea79171 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -644,6 +644,7 @@ queue_pages_range(struct mm_struct *mm, unsigned long
start, unsigned long end,
.nmask = nodes,
.prev = NULL,
};
+ int err;
struct mm_walk queue_pages_walk = {
.hugetlb_entry = queue_pages_hugetlb,
.pmd_entry = queue_pages_pte_range,
@@ -652,7 +653,10 @@ queue_pages_range(struct mm_struct *mm, unsigned long
start, unsigned long end,
.private = &qp,
};
- return walk_page_range(start, end, &queue_pages_walk);
+ err = walk_page_range(start, end, &queue_pages_walk);
+ if (err < 0)
+ return err;
+ return 0;
}
/*
I'm afraid I don't think this is the right fix, if walk_page_range()
returns a positive value then it should be supplied by one of the
callbacks in the struct mm_walk, which none of these happen to do. I
think this may be a problem with commit 6f4576e3687b ("mempolicy: apply
page table walker on queue_pages_range()"), so let's add Naoya to the
thread.
Thank you for the pointer!
I think queue_pages_test_walk() returns 1.
My fix may not be in a right place but someone needs to fix this.
- kaz
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