eal: change max hugepage sizes to 4
Checks
Commit Message
DPDK currently is supporting maximum 3 hugepage,
sizes whereas system can support more than this e.g.
64K, 2M, 32M and 1G.
Having these four hugepage sizes available to use by DPDK,
which is valid in case of '--in-memory' EAL option or
using 4 separate mount points for each hugepage size;
hugepage_info_init() API reports an error.
This change increases the maximum supported mount points
to 4.
Signed-off-by: Gagandeep Singh <g.singh@nxp.com>
Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
---
On ARM platform when the translation granule is 4KB,
there are 4 hugepage sizes supported.
On kernel 5.2, we can see below directories in
/sys/kernel/mm/hugepages:
hugepages-1048576kB
hugepages-2048kB
hugepages-32768kB
hugepages-64kB
lib/librte_eal/common/eal_internal_cfg.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Comments
On Wed, Aug 7, 2019 at 12:26 PM Gagandeep Singh <g.singh@nxp.com> wrote:
>
> DPDK currently is supporting maximum 3 hugepage,
> sizes whereas system can support more than this e.g.
> 64K, 2M, 32M and 1G.
You can mention ARM platform here, and that this issue starts with
kernel 5.2 (and I would try to mention this in the title as well).
This is better than an annotation that will be lost.
> Having these four hugepage sizes available to use by DPDK,
> which is valid in case of '--in-memory' EAL option or
> using 4 separate mount points for each hugepage size;
> hugepage_info_init() API reports an error.
Can you describe what is the impact from a user point of view rather
than mentioning this internal function?
> This change increases the maximum supported mount points
> to 4.
I suppose this fix does the trick for you.
However, we are in internal structures and I can't think of an impact
on datapath.
So we might as well use dynamic allocations rather than just enlarge this array.
Did you consider this?
07/08/2019 14:00, David Marchand:
> On Wed, Aug 7, 2019 at 12:26 PM Gagandeep Singh <g.singh@nxp.com> wrote:
> >
> > DPDK currently is supporting maximum 3 hugepage,
> > sizes whereas system can support more than this e.g.
> > 64K, 2M, 32M and 1G.
>
> You can mention ARM platform here, and that this issue starts with
> kernel 5.2 (and I would try to mention this in the title as well).
> This is better than an annotation that will be lost.
>
>
> > Having these four hugepage sizes available to use by DPDK,
> > which is valid in case of '--in-memory' EAL option or
> > using 4 separate mount points for each hugepage size;
> > hugepage_info_init() API reports an error.
>
> Can you describe what is the impact from a user point of view rather
> than mentioning this internal function?
Yes please, we need to understand how much it is critical.
Should we Cc stable@dpdk.org for backport?
Should it be merged at the last minute in 19.08?
> > This change increases the maximum supported mount points
> > to 4.
>
> I suppose this fix does the trick for you.
> However, we are in internal structures and I can't think of an impact
> on datapath.
> So we might as well use dynamic allocations rather than just enlarge this array.
>
> Did you consider this?
HI Thomas,
> > > DPDK currently is supporting maximum 3 hugepage, sizes whereas
> > > system can support more than this e.g.
> > > 64K, 2M, 32M and 1G.
> >
> > You can mention ARM platform here, and that this issue starts with
> > kernel 5.2 (and I would try to mention this in the title as well).
> > This is better than an annotation that will be lost.
> >
> >
> > > Having these four hugepage sizes available to use by DPDK, which is
> > > valid in case of '--in-memory' EAL option or using 4 separate mount
> > > points for each hugepage size;
> > > hugepage_info_init() API reports an error.
> >
> > Can you describe what is the impact from a user point of view rather
> > than mentioning this internal function?
>
> Yes please, we need to understand how much it is critical.
> Should we Cc stable@dpdk.org for backport?
> Should it be merged at the last minute in 19.08?
>
VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work without this patch.
On Wed, 7 Aug 2019 15:42:04 +0530
Gagandeep Singh <g.singh@nxp.com> wrote:
> DPDK currently is supporting maximum 3 hugepage,
> sizes whereas system can support more than this e.g.
> 64K, 2M, 32M and 1G.
>
> Having these four hugepage sizes available to use by DPDK,
> which is valid in case of '--in-memory' EAL option or
> using 4 separate mount points for each hugepage size;
> hugepage_info_init() API reports an error.
>
> This change increases the maximum supported mount points
> to 4.
>
> Signed-off-by: Gagandeep Singh <g.singh@nxp.com>
> Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
> ---
>
> On ARM platform when the translation granule is 4KB,
> there are 4 hugepage sizes supported.
> On kernel 5.2, we can see below directories in
> /sys/kernel/mm/hugepages:
>
> hugepages-1048576kB
> hugepages-2048kB
> hugepages-32768kB
> hugepages-64kB
>
> lib/librte_eal/common/eal_internal_cfg.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/librte_eal/common/eal_internal_cfg.h b/lib/librte_eal/common/eal_internal_cfg.h
> index edff09d07..abb7ec913 100644
> --- a/lib/librte_eal/common/eal_internal_cfg.h
> +++ b/lib/librte_eal/common/eal_internal_cfg.h
> @@ -15,7 +15,7 @@
>
> #include "eal_thread.h"
>
> -#define MAX_HUGEPAGE_SIZES 3 /**< support up to 3 page sizes */
> +#define MAX_HUGEPAGE_SIZES 4 /**< support up to 4 page sizes */
At least this is hidden in internal config.
07/08/2019 15:28, Hemant Agrawal:
> HI Thomas,
>
> > > > DPDK currently is supporting maximum 3 hugepage, sizes whereas
> > > > system can support more than this e.g.
> > > > 64K, 2M, 32M and 1G.
> > >
> > > You can mention ARM platform here, and that this issue starts with
> > > kernel 5.2 (and I would try to mention this in the title as well).
> > > This is better than an annotation that will be lost.
> > >
> > >
> > > > Having these four hugepage sizes available to use by DPDK, which is
> > > > valid in case of '--in-memory' EAL option or using 4 separate mount
> > > > points for each hugepage size;
> > > > hugepage_info_init() API reports an error.
> > >
> > > Can you describe what is the impact from a user point of view rather
> > > than mentioning this internal function?
> >
> > Yes please, we need to understand how much it is critical.
> > Should we Cc stable@dpdk.org for backport?
> > Should it be merged at the last minute in 19.08?
>
> VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work without this patch.
Do you want to send a v2 with a better explanation?
I would suggest to restrict the change to Arm only with an ifdef,
in order to limit the risk for this release.
We can think about a dynamic hugepage scan in the next release.
On Wed, Aug 7, 2019 at 3:28 PM Hemant Agrawal <hemant.agrawal@nxp.com> wrote:
>
> HI Thomas,
>
> > > > DPDK currently is supporting maximum 3 hugepage, sizes whereas
> > > > system can support more than this e.g.
> > > > 64K, 2M, 32M and 1G.
> > >
> > > You can mention ARM platform here, and that this issue starts with
> > > kernel 5.2 (and I would try to mention this in the title as well).
> > > This is better than an annotation that will be lost.
> > >
> > >
> > > > Having these four hugepage sizes available to use by DPDK, which is
> > > > valid in case of '--in-memory' EAL option or using 4 separate mount
> > > > points for each hugepage size;
> > > > hugepage_info_init() API reports an error.
> > >
> > > Can you describe what is the impact from a user point of view rather
> > > than mentioning this internal function?
> >
> > Yes please, we need to understand how much it is critical.
> > Should we Cc stable@dpdk.org for backport?
> > Should it be merged at the last minute in 19.08?
> >
>
> VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work without this patch.
>
I have been looking at the changes in the linux kernel.
Can you pinpoint at the commit that changed this in 5.2?
I can see a change in the code, but in 5.0, or maybe something changed
in the configuration.
The patch you propose is not that risky (x86 supports two pagesizes,
and max hugepage is already at 3, so we know the code works fine with
less than the max).
Yet, I want to understand why this is urgent now.
CCing other architecture maintainers.
> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Thursday, August 8, 2019 1:03 PM
> To: Hemant Agrawal <hemant.agrawal@nxp.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>; Gagandeep Singh
> <G.Singh@nxp.com>; dev <dev@dpdk.org>; Burakov, Anatoly
> <anatoly.burakov@intel.com>; Olivier Matz <olivier.matz@6wind.com>;
> Andrew Rybchenko <arybchenko@solarflare.com>; Nipun Gupta
> <nipun.gupta@nxp.com>; Jerin Jacob Kollanukkaran <jerinj@marvell.com>;
> Gavin Hu <gavin.hu@arm.com>; Bruce Richardson
> <bruce.richardson@intel.com>
> Subject: [EXT] Re: [dpdk-dev] [PATCH] eal: change max hugepage sizes to 4
> On Wed, Aug 7, 2019 at 3:28 PM Hemant Agrawal <hemant.agrawal@nxp.com>
> wrote:
> >
> > HI Thomas,
> >
> > > > > DPDK currently is supporting maximum 3 hugepage, sizes whereas
> > > > > system can support more than this e.g.
> > > > > 64K, 2M, 32M and 1G.
> > > >
> > > > You can mention ARM platform here, and that this issue starts with
> > > > kernel 5.2 (and I would try to mention this in the title as well).
> > > > This is better than an annotation that will be lost.
> > > >
> > > >
> > > > > Having these four hugepage sizes available to use by DPDK, which
> > > > > is valid in case of '--in-memory' EAL option or using 4 separate
> > > > > mount points for each hugepage size;
> > > > > hugepage_info_init() API reports an error.
> > > >
> > > > Can you describe what is the impact from a user point of view
> > > > rather than mentioning this internal function?
> > >
> > > Yes please, we need to understand how much it is critical.
> > > Should we Cc stable@dpdk.org for backport?
> > > Should it be merged at the last minute in 19.08?
> > >
> >
> > VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work
> without this patch.
> >
>
> I have been looking at the changes in the linux kernel.
> Can you pinpoint at the commit that changed this in 5.2?
>
> I can see a change in the code, but in 5.0, or maybe something changed in the
> configuration.
>
> The patch you propose is not that risky (x86 supports two pagesizes, and max
> hugepage is already at 3, so we know the code works fine with less than the
> max).
> Yet, I want to understand why this is urgent now.
>
> CCing other architecture maintainers.
Tested this change with an arm64 machine + 4.18 kernel. Looks OK.
Tested-by: Jerin Jacob <jerinj@marvell.com>
>
>
> --
> David Marchand
Hi David,
> > VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work
> without this patch.
> >
>
> I have been looking at the changes in the linux kernel.
> Can you pinpoint at the commit that changed this in 5.2?
>
> I can see a change in the code, but in 5.0, or maybe something changed in the
> configuration.
[Hemant] I am not aware of exact patch, which changed the behavior. May be Honnappa/Steve can help here.
Regards,
Hemant
>
> The patch you propose is not that risky (x86 supports two pagesizes, and max
> hugepage is already at 3, so we know the code works fine with less than the
> max).
> Yet, I want to understand why this is urgent now.
>
> CCing other architecture maintainers.
>
>
> --
> David Marchand
Hello,
On Thu, Aug 08, 2019 at 10:37:20AM +0000, Hemant Agrawal wrote:
> Hi David,
>
> > > VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work
> > without this patch.
> > >
> >
> > I have been looking at the changes in the linux kernel.
> > Can you pinpoint at the commit that changed this in 5.2?
> >
> > I can see a change in the code, but in 5.0, or maybe something changed in the
> > configuration.
>
> [Hemant] I am not aware of exact patch, which changed the behavior. May be Honnappa/Steve can help here.
>
All the possible hugetlb sizes being advertised was added in v5.0 by:
a21b0b78eaf7 arm64: hugetlb: Register hugepages during arch init
(Some more recent patches changed the constants used but the logic
remained the same).
Cheers,
On Thu, Aug 8, 2019 at 2:29 PM Steve Capper <Steve.Capper@arm.com> wrote:
>
> Hello,
>
> On Thu, Aug 08, 2019 at 10:37:20AM +0000, Hemant Agrawal wrote:
> > Hi David,
> >
> > > > VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work
> > > without this patch.
> > > >
> > >
> > > I have been looking at the changes in the linux kernel.
> > > Can you pinpoint at the commit that changed this in 5.2?
> > >
> > > I can see a change in the code, but in 5.0, or maybe something changed in the
> > > configuration.
> >
> > [Hemant] I am not aware of exact patch, which changed the behavior. May be Honnappa/Steve can help here.
> >
>
> All the possible hugetlb sizes being advertised was added in v5.0 by:
> a21b0b78eaf7 arm64: hugetlb: Register hugepages during arch init
>
> (Some more recent patches changed the constants used but the logic
> remained the same).
Ah, thanks for confirming :-).
On 07-Aug-19 2:28 PM, Hemant Agrawal wrote:
> HI Thomas,
>
>>>> DPDK currently is supporting maximum 3 hugepage, sizes whereas
>>>> system can support more than this e.g.
>>>> 64K, 2M, 32M and 1G.
>>>
>>> You can mention ARM platform here, and that this issue starts with
>>> kernel 5.2 (and I would try to mention this in the title as well).
>>> This is better than an annotation that will be lost.
>>>
>>>
>>>> Having these four hugepage sizes available to use by DPDK, which is
>>>> valid in case of '--in-memory' EAL option or using 4 separate mount
>>>> points for each hugepage size;
>>>> hugepage_info_init() API reports an error.
>>>
>>> Can you describe what is the impact from a user point of view rather
>>> than mentioning this internal function?
>>
>> Yes please, we need to understand how much it is critical.
>> Should we Cc stable@dpdk.org for backport?
>> Should it be merged at the last minute in 19.08?
>>
>
> VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work without this patch.
>
Off-topic, but it's nice to see real-world usage for this option!
On 08-Aug-19 8:31 AM, Thomas Monjalon wrote:
> 07/08/2019 15:28, Hemant Agrawal:
>> HI Thomas,
>>
>>>>> DPDK currently is supporting maximum 3 hugepage, sizes whereas
>>>>> system can support more than this e.g.
>>>>> 64K, 2M, 32M and 1G.
>>>>
>>>> You can mention ARM platform here, and that this issue starts with
>>>> kernel 5.2 (and I would try to mention this in the title as well).
>>>> This is better than an annotation that will be lost.
>>>>
>>>>
>>>>> Having these four hugepage sizes available to use by DPDK, which is
>>>>> valid in case of '--in-memory' EAL option or using 4 separate mount
>>>>> points for each hugepage size;
>>>>> hugepage_info_init() API reports an error.
>>>>
>>>> Can you describe what is the impact from a user point of view rather
>>>> than mentioning this internal function?
>>>
>>> Yes please, we need to understand how much it is critical.
>>> Should we Cc stable@dpdk.org for backport?
>>> Should it be merged at the last minute in 19.08?
>>
>> VPP usages in-memory option. So, VPP on ARM with kernel 5.2 wont' work without this patch.
>
> Do you want to send a v2 with a better explanation?
>
> I would suggest to restrict the change to Arm only with an ifdef,
> in order to limit the risk for this release.
> We can think about a dynamic hugepage scan in the next release.
>
I don't see how this is necessary. The 3 is an arbitrary number here,
and the ABI isn't broken as this is an internal structure. We could
increase it to 16 for all i care, and it wouldn't make any difference to
the rest of the code - we never populate more than we can find anyway.
On Mon, Aug 12, 2019 at 11:43 AM Burakov, Anatoly
<anatoly.burakov@intel.com> wrote:
> On 08-Aug-19 8:31 AM, Thomas Monjalon wrote:
> > I would suggest to restrict the change to Arm only with an ifdef,
> > in order to limit the risk for this release.
> > We can think about a dynamic hugepage scan in the next release.
> >
>
> I don't see how this is necessary. The 3 is an arbitrary number here,
> and the ABI isn't broken as this is an internal structure. We could
> increase it to 16 for all i care, and it wouldn't make any difference to
> the rest of the code - we never populate more than we can find anyway.
I agree on the principle.
But at the time this popped up, we were really close to the release.
It seemed a way to mitigate any unforeseen issue by limiting to the
platform that was affected.
12/08/2019 11:49, David Marchand:
> On Mon, Aug 12, 2019 at 11:43 AM Burakov, Anatoly
> <anatoly.burakov@intel.com> wrote:
> > On 08-Aug-19 8:31 AM, Thomas Monjalon wrote:
> > > I would suggest to restrict the change to Arm only with an ifdef,
> > > in order to limit the risk for this release.
> > > We can think about a dynamic hugepage scan in the next release.
> >
> > I don't see how this is necessary. The 3 is an arbitrary number here,
> > and the ABI isn't broken as this is an internal structure. We could
> > increase it to 16 for all i care, and it wouldn't make any difference to
> > the rest of the code - we never populate more than we can find anyway.
>
> I agree on the principle.
> But at the time this popped up, we were really close to the release.
> It seemed a way to mitigate any unforeseen issue by limiting to the
> platform that was affected.
Exactly, we were extra cautious.
Please increase the value for everybody, thanks.
On 12-Aug-19 10:49 AM, David Marchand wrote:
> On Mon, Aug 12, 2019 at 11:43 AM Burakov, Anatoly
> <anatoly.burakov@intel.com> wrote:
>> On 08-Aug-19 8:31 AM, Thomas Monjalon wrote:
>>> I would suggest to restrict the change to Arm only with an ifdef,
>>> in order to limit the risk for this release.
>>> We can think about a dynamic hugepage scan in the next release.
>>>
>>
>> I don't see how this is necessary. The 3 is an arbitrary number here,
>> and the ABI isn't broken as this is an internal structure. We could
>> increase it to 16 for all i care, and it wouldn't make any difference to
>> the rest of the code - we never populate more than we can find anyway.
>
> I agree on the principle.
> But at the time this popped up, we were really close to the release.
> It seemed a way to mitigate any unforeseen issue by limiting to the
> platform that was affected.
>
Fair enough. A follow up is needed so. Frankly, i don't see the need to
complicate things with "dynamic" stuff here - a static array of 8 or 16
page sizes should be enough for everyone (TM).
@@ -15,7 +15,7 @@
#include "eal_thread.h"
-#define MAX_HUGEPAGE_SIZES 3 /**< support up to 3 page sizes */
+#define MAX_HUGEPAGE_SIZES 4 /**< support up to 4 page sizes */
/*
* internal configuration structure for the number, size and