[ofa-general] Re: [PATCH v3] mlx4_ib: Optimize hugetlab pages support
Yossi Etigin
yosefe at voltaire.com
Mon Apr 13 12:19:08 PDT 2009
Eli Cohen wrote:
> On Mon, Apr 06, 2009 at 08:49:43PM +0300, Yossi Etigin wrote:
>> I don't understand - if all area is huge pages, it does not mean that
>> it fills full huge pages - I can have just 4096 bytes in huge page memory
>> and umem->hugetlb will remain 1, right?
>
> You may call ib_umem_get() with a fraction of a huge page but I expect
> the number of pages returned from get_user_pages() will fill up a huge
> page. Can you check that with the mckey test you were using?
The number of pages is 1.
I got this in dmesg with the modified mckey (see the last line):
umem: addr=508000 size=1024 hugetlb=0 npages=1
umem: addr=50a000 size=4096 hugetlb=0 npages=1
umem: addr=50c000 size=4352 hugetlb=0 npages=2
umem: addr=50f000 size=4096 hugetlb=0 npages=1
umem: addr=2aaaaac00000 size=140 hugetlb=1 npages=1
After applying this to umem.c:
--- ofa_kernel-1.4.1/drivers/infiniband/core/umem.c 2009-04-13 22:15:19.000000000 +0300
+++ ofa_kernel-1.4.1.patched/drivers/infiniband/core/umem.c 2009-04-13 22:09:36.000000000 +0300
@@ -137,6 +137,7 @@
int ret;
int off;
int i;
+ int ntotalpages;
DEFINE_DMA_ATTRS(attrs);
if (dmasync)
@@ -196,6 +197,7 @@
cur_base = addr & PAGE_MASK;
ret = 0;
+ ntotalpages = 0;
while (npages) {
ret = get_user_pages(current, current->mm, cur_base,
min_t(unsigned long, npages,
@@ -226,6 +228,7 @@
!is_vm_hugetlb_page(vma_list[i + off]))
umem->hugetlb = 0;
sg_set_page(&chunk->page_list[i], page_list[i + off], PAGE_SIZE, 0);
+ ntotalpages++;
}
chunk->nmap = ib_dma_map_sg_attrs(context->device,
@@ -254,8 +257,11 @@
if (ret < 0) {
__ib_umem_release(context->device, umem, 0);
kfree(umem);
- } else
+ } else {
current->mm->locked_vm = locked;
+ printk(KERN_DEBUG "umem: addr=%lx size=%ld hugetlb=%d npages=%d\n",
+ addr, size, umem->hugetlb, ntotalpages);
+ }
up_write(¤t->mm->mmap_sem);
if (vma_list)
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