diff mbox

[dpdk-dev,1/2] eal/ppc: fix mmap for memory initialization

Message ID 1491473170-25160-2-git-send-email-chaozhu@linux.vnet.ibm.com (mailing list archive)
State Accepted, archived
Delegated to: Thomas Monjalon
Headers

Checks

Context Check Description
ci/checkpatch warning coding style issues
ci/Intel-compilation success Compilation OK

Commit Message

Chao Zhu April 6, 2017, 10:06 a.m. UTC 
  On IBM POWER platform, when mapping /dev/zero file to hugepage memory
space, mmap will not respect the requested address hint. This will cause
the memory initilization for the second process fails. This patch adds
the required mmap flags to make it work. Beside this, users need to set
the nr_overcommit_hugepages to expand the VA range. When
doing the initilization, users need to set both nr_hugepages and
nr_overcommit_hugepages to the same value, like 64, 128, etc.

Signed-off-by: Chao Zhu <chaozhu@linux.vnet.ibm.com>
---
 lib/librte_eal/linuxapp/eal/eal_memory.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Sergio Gonzalez Monroy April 6, 2017, 12:58 p.m. UTC | #1 
Hi Chao,

You mentioned that 'mmap will not respect the requested address hint', 
how does the proposed change solves that?

Is it that hugepages map to a specific VA region, and without 
MAP_HUGETLB you may get address from wrong region?

If mmap were to respect the hinted address, we could do this change 
multi-arch without having to set overcommit hugepages?

fd = -1
addr = mmap(addr, (*size) + hugepage_sz, PROT_READ, MAP_PRIVATE | 
MAP_ANONYMOUS | MAP_HUGETLB, fd, 0)
# Free hugepages mapping
addr = mmap(addr, (*size) + hugepage_sz, PROT_READ, MAP_PRIVATE | 
MAP_ANONYMOUS, fd, 0)

What do you think?

Regards,
Sergio

On 06/04/2017 11:06, Chao Zhu wrote:
> On IBM POWER platform, when mapping /dev/zero file to hugepage memory
> space, mmap will not respect the requested address hint. This will cause
> the memory initilization for the second process fails. This patch adds
> the required mmap flags to make it work. Beside this, users need to set
> the nr_overcommit_hugepages to expand the VA range. When
> doing the initilization, users need to set both nr_hugepages and
> nr_overcommit_hugepages to the same value, like 64, 128, etc.
>
> Signed-off-by: Chao Zhu <chaozhu@linux.vnet.ibm.com>
> ---
>   lib/librte_eal/linuxapp/eal/eal_memory.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index a956bb2..e06186b 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -313,7 +313,11 @@ int rte_xen_dom0_supported(void)
>   	}
>   	do {
>   		addr = mmap(addr,
> +#ifndef RTE_ARCH_PPC_64
>   				(*size) + hugepage_sz, PROT_READ, MAP_PRIVATE, fd, 0);
> +#else
> +                (*size) + hugepage_sz, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, fd, 0);
> +#endif
>   		if (addr == MAP_FAILED)
>   			*size -= hugepage_sz;
>   	} while (addr == MAP_FAILED && *size > 0);
> @@ -1330,7 +1334,11 @@ static int huge_wrap_sigsetjmp(void)
>   		 * use mmap to get identical addresses as the primary process.
>   		 */
>   		base_addr = mmap(mcfg->memseg[s].addr, mcfg->memseg[s].len,
> +#ifndef RTE_ARCH_PPC_64
>   				 PROT_READ, MAP_PRIVATE, fd_zero, 0);
> +#else
> +                 PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, fd_zero, 0);
> +#endif
>   		if (base_addr == MAP_FAILED ||
>   		    base_addr != mcfg->memseg[s].addr) {
>   			max_seg = s;
Chao Zhu April 13, 2017, 1:40 a.m. UTC | #2 
Sergio,

Thanks for the comments!
On POWER, if it doesn't specify the MAP_HUGETLB flag when doing mapping, it
may get the addresses from other regions. However, the address space size of
hugepages is exactly the same as the value specified by user when doing
initialization. There will be not enough space for mmap twice in DPDK.
That's why we need to set the overcommit to expand the address space.

> -----Original Message-----
> From: Sergio Gonzalez Monroy [mailto:sergio.gonzalez.monroy@intel.com]
> Sent: 2017年4月6日 20:59
> To: Chao Zhu <chaozhu@linux.vnet.ibm.com>; dev@dpdk.org
> Cc: Gowrishankar <gowrishankar.m@linux.vnet.ibm.com>;
> david.marchand@6wind.com
> Subject: Re: [PATCH 1/2] eal/ppc: fix mmap for memory initialization
> 
> Hi Chao,
> 
> You mentioned that 'mmap will not respect the requested address hint', how
> does the proposed change solves that?
> 
> Is it that hugepages map to a specific VA region, and without MAP_HUGETLB
> you may get address from wrong region?
> 
> If mmap were to respect the hinted address, we could do this change
> multi-arch without having to set overcommit hugepages?
> 
> fd = -1
> addr = mmap(addr, (*size) + hugepage_sz, PROT_READ, MAP_PRIVATE |
> MAP_ANONYMOUS | MAP_HUGETLB, fd, 0) # Free hugepages mapping addr =
> mmap(addr, (*size) + hugepage_sz, PROT_READ, MAP_PRIVATE |
> MAP_ANONYMOUS, fd, 0)
> 
> What do you think?
> 
> Regards,
> Sergio
> 
> On 06/04/2017 11:06, Chao Zhu wrote:
> > On IBM POWER platform, when mapping /dev/zero file to hugepage memory
> > space, mmap will not respect the requested address hint. This will
> > cause the memory initilization for the second process fails. This
> > patch adds the required mmap flags to make it work. Beside this, users
> > need to set the nr_overcommit_hugepages to expand the VA range. When
> > doing the initilization, users need to set both nr_hugepages and
> > nr_overcommit_hugepages to the same value, like 64, 128, etc.
> >
> > Signed-off-by: Chao Zhu <chaozhu@linux.vnet.ibm.com>
> > ---
> >   lib/librte_eal/linuxapp/eal/eal_memory.c | 8 ++++++++
> >   1 file changed, 8 insertions(+)
> >
> > diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c
> > b/lib/librte_eal/linuxapp/eal/eal_memory.c
> > index a956bb2..e06186b 100644
> > --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> > +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> > @@ -313,7 +313,11 @@ int rte_xen_dom0_supported(void)
> >   	}
> >   	do {
> >   		addr = mmap(addr,
> > +#ifndef RTE_ARCH_PPC_64
> >   				(*size) + hugepage_sz, PROT_READ,
MAP_PRIVATE, fd,
> 0);
> > +#else
> > +                (*size) + hugepage_sz, PROT_READ, MAP_PRIVATE |
> > +MAP_ANONYMOUS | MAP_HUGETLB, fd, 0); #endif
> >   		if (addr == MAP_FAILED)
> >   			*size -= hugepage_sz;
> >   	} while (addr == MAP_FAILED && *size > 0); @@ -1330,7 +1334,11
> @@
> > static int huge_wrap_sigsetjmp(void)
> >   		 * use mmap to get identical addresses as the primary
process.
> >   		 */
> >   		base_addr = mmap(mcfg->memseg[s].addr,
> mcfg->memseg[s].len,
> > +#ifndef RTE_ARCH_PPC_64
> >   				 PROT_READ, MAP_PRIVATE, fd_zero, 0);
> > +#else
> > +                 PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS |
> > +MAP_HUGETLB, fd_zero, 0); #endif
> >   		if (base_addr == MAP_FAILED ||
> >   		    base_addr != mcfg->memseg[s].addr) {
> >   			max_seg = s;
>
Sergio Gonzalez Monroy April 13, 2017, 8:14 a.m. UTC | #3 
On 06/04/2017 11:06, Chao Zhu wrote:
> On IBM POWER platform, when mapping /dev/zero file to hugepage memory
> space, mmap will not respect the requested address hint. This will cause
> the memory initilization for the second process fails. This patch adds
> the required mmap flags to make it work. Beside this, users need to set
> the nr_overcommit_hugepages to expand the VA range. When
> doing the initilization, users need to set both nr_hugepages and
> nr_overcommit_hugepages to the same value, like 64, 128, etc.
>
> Signed-off-by: Chao Zhu <chaozhu@linux.vnet.ibm.com>
> ---
>   lib/librte_eal/linuxapp/eal/eal_memory.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
> index a956bb2..e06186b 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
> @@ -313,7 +313,11 @@ int rte_xen_dom0_supported(void)
>   	}
>   	do {
>   		addr = mmap(addr,
> +#ifndef RTE_ARCH_PPC_64
>   				(*size) + hugepage_sz, PROT_READ, MAP_PRIVATE, fd, 0);
> +#else
> +                (*size) + hugepage_sz, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, fd, 0);
> +#endif
>   		if (addr == MAP_FAILED)
>   			*size -= hugepage_sz;
>   	} while (addr == MAP_FAILED && *size > 0);
> @@ -1330,7 +1334,11 @@ static int huge_wrap_sigsetjmp(void)
>   		 * use mmap to get identical addresses as the primary process.
>   		 */
>   		base_addr = mmap(mcfg->memseg[s].addr, mcfg->memseg[s].len,
> +#ifndef RTE_ARCH_PPC_64
>   				 PROT_READ, MAP_PRIVATE, fd_zero, 0);
> +#else
> +                 PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, fd_zero, 0);
> +#endif
>   		if (base_addr == MAP_FAILED ||
>   		    base_addr != mcfg->memseg[s].addr) {
>   			max_seg = s;


Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
Thomas Monjalon April 20, 2017, 7:41 a.m. UTC | #4 
13/04/2017 10:14, Sergio Gonzalez Monroy:
> On 06/04/2017 11:06, Chao Zhu wrote:
> > On IBM POWER platform, when mapping /dev/zero file to hugepage memory
> > space, mmap will not respect the requested address hint. This will cause
> > the memory initilization for the second process fails. This patch adds
> > the required mmap flags to make it work. Beside this, users need to set
> > the nr_overcommit_hugepages to expand the VA range. When
> > doing the initilization, users need to set both nr_hugepages and
> > nr_overcommit_hugepages to the same value, like 64, 128, etc.
> > 
> > Signed-off-by: Chao Zhu <chaozhu@linux.vnet.ibm.com>
> 
> Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>

Series fixed, squashed and applied, thanks
diff mbox

Patch

diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index a956bb2..e06186b 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -313,7 +313,11 @@  int rte_xen_dom0_supported(void)
 	}
 	do {
 		addr = mmap(addr,
+#ifndef RTE_ARCH_PPC_64
 				(*size) + hugepage_sz, PROT_READ, MAP_PRIVATE, fd, 0);
+#else
+                (*size) + hugepage_sz, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, fd, 0);
+#endif
 		if (addr == MAP_FAILED)
 			*size -= hugepage_sz;
 	} while (addr == MAP_FAILED && *size > 0);
@@ -1330,7 +1334,11 @@  static int huge_wrap_sigsetjmp(void)
 		 * use mmap to get identical addresses as the primary process.
 		 */
 		base_addr = mmap(mcfg->memseg[s].addr, mcfg->memseg[s].len,
+#ifndef RTE_ARCH_PPC_64
 				 PROT_READ, MAP_PRIVATE, fd_zero, 0);
+#else
+                 PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, fd_zero, 0);
+#endif
 		if (base_addr == MAP_FAILED ||
 		    base_addr != mcfg->memseg[s].addr) {
 			max_seg = s;