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<blockquote cite="mid:87y4893ar2.fsf@skywalker.in.ibm.com"
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<pre wrap="">Michael Ellerman <a class="moz-txt-link-rfc2396E" href="mailto:mpe@ellerman.id.au"><mpe@ellerman.id.au></a> writes:
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<pre wrap="">On Fri, 2016-19-02 at 05:38:47 UTC, Rashmica Gupta wrote:
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<pre wrap="">Currently on PPC64 changing kernel pagesize from 4K to 64K leaves
FORCE_MAX_ZONEORDER set to 13 - which produces a compile error.
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<pre wrap="">...
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<pre wrap="">So, update the range of FORCE_MAX_ZONEORDER from 9-64 to 8-9 for 64K pages
and from 13-64 to 9-13 for 4K pages.
Signed-off-by: Rashmica Gupta <a class="moz-txt-link-rfc2396E" href="mailto:rashmicy@gmail.com"><rashmicy@gmail.com></a>
Reviewed-by: Balbir Singh <a class="moz-txt-link-rfc2396E" href="mailto:bsingharora@gmail.com"><bsingharora@gmail.com></a>
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Applied to powerpc next, thanks.
<a class="moz-txt-link-freetext" href="https://git.kernel.org/powerpc/c/a7ee539584acf4a565b7439cea">https://git.kernel.org/powerpc/c/a7ee539584acf4a565b7439cea</a>
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<pre wrap="">
HPAGE_PMD_ORDER is not something we should check w.r.t 4k linux page
size. We do have the below constraint w.r.t hugetlb pages
static inline bool hstate_is_gigantic(struct hstate *h)
{
return huge_page_order(h) >= MAX_ORDER;
}
That require MAX_ORDER to be greater than 12.
Did we test hugetlbfs 4k config with this patch ? Will it work if we
start marking hugepage as gigantic page ?
-aneesh
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Hello Rashmica,<br>
<br>
With upstream linux kernel 4.8.0-rc1-00006-gbae9cc6 compiled with
linux 4k page size we are not able set hugepages, Aneesh had a look
at the problem and he mentioned this commit is causing the issue.<br>
<br>
<b>Details:</b><br>
We are using pkvm ubuntu 16.04 guest with upstream kernel
[4.8.0-rc1-00006-gbae9cc6] compiled with 4k page size<br>
<br>
o/p from guest:<br>
HugePages_Total: 0<br>
HugePages_Free: 0<br>
HugePages_Rsvd: 0<br>
HugePages_Surp: 0<br>
Hugepagesize: 16384 kB<br>
<br>
Page sizes from device-tree: [dmesg]<br>
[ 0.000000] base_shift=12: shift=12, sllp=0x0000,
avpnm=0x00000000, tlbiel=1, penc=0<br>
[ 0.000000] base_shift=12: shift=24, sllp=0x0000,
avpnm=0x00000000, tlbiel=1, penc=56<br>
[ 0.000000] base_shift=24: shift=24, sllp=0x0100,
avpnm=0x00000001, tlbiel=0, penc=0<br>
<br>
while trying to configure the hugepages inside the guest it throws
the below error:<br>
<br>
echo 100 > /proc/sys/vm/nr_hugepages<br>
-bash: echo: write error: Invalid argument<br>
<br>
<b>Note</b>: we do not see the problem when the linux page is 64k<br>
<br>
Thanks,<br>
Santhosh G<br>
<br>
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