* [PATCH] mm/hugetlb: Fix incorrect proc nr_hugepages value
@ 2016-02-16 19:43 Vaishali Thakkar
2016-02-17 3:37 ` Naoya Horiguchi
2016-02-17 9:59 ` Kirill A. Shutemov
0 siblings, 2 replies; 4+ messages in thread
From: Vaishali Thakkar @ 2016-02-16 19:43 UTC (permalink / raw)
To: Andrew Morton
Cc: n-horiguchi, mike.kravetz, hillf.zj, kirill.shutemov,
dave.hansen, paul.gortmaker, linux-mm, linux-kernel,
Vaishali Thakkar
Currently incorrect default hugepage pool size is reported by proc
nr_hugepages when number of pages for the default huge page size is
specified twice.
When multiple huge page sizes are supported, /proc/sys/vm/nr_hugepages
indicates the current number of pre-allocated huge pages of the default
size. Basically /proc/sys/vm/nr_hugepages displays default_hstate->
max_huge_pages and after boot time pre-allocation, max_huge_pages should
equal the number of pre-allocated pages (nr_hugepages).
Test case:
Note that this is specific to x86 architecture.
Boot the kernel with command line option 'default_hugepagesz=1G
hugepages=X hugepagesz=2M hugepages=Y hugepagesz=1G hugepages=Z'. After
boot, 'cat /proc/sys/vm/nr_hugepages' and 'sysctl -a | grep hugepages'
returns the value X. However, dmesg output shows that Z huge pages were
pre-allocated.
So, the root cause of the problem here is that the global variable
default_hstate_max_huge_pages is set if a default huge page size is
specified (directly or indirectly) on the command line. After the
command line processing in hugetlb_init, if default_hstate_max_huge_pages
is set, the value is assigned to default_hstae.max_huge_pages. However,
default_hstate.max_huge_pages may have already been set based on the
number of pre-allocated huge pages of default_hstate size.
The solution to this problem is if hstate->max_huge_pages is already set
then it should not set as a result of global max_huge_pages value.
Basically if the value of the variable hugepages is set multiple times
on a command line for a specific supported hugepagesize then proc layer
should consider the last specified value.
Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
---
The patch contains one line over 80 characters as I think limiting that
line to 80 characters makes code look bit ugly. But if anyone is having
issue with that then I am fine with limiting it to 80 chracters.
---
mm/hugetlb.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 06ae13e..01f2b48 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2630,8 +2630,10 @@ static int __init hugetlb_init(void)
hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
}
default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
- if (default_hstate_max_huge_pages)
- default_hstate.max_huge_pages = default_hstate_max_huge_pages;
+ if (default_hstate_max_huge_pages) {
+ if (!default_hstate.max_huge_pages)
+ default_hstate.max_huge_pages = default_hstate_max_huge_pages;
+ }
hugetlb_init_hstates();
gather_bootmem_prealloc();
--
2.1.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/hugetlb: Fix incorrect proc nr_hugepages value
2016-02-16 19:43 [PATCH] mm/hugetlb: Fix incorrect proc nr_hugepages value Vaishali Thakkar
@ 2016-02-17 3:37 ` Naoya Horiguchi
2016-02-17 9:59 ` Kirill A. Shutemov
1 sibling, 0 replies; 4+ messages in thread
From: Naoya Horiguchi @ 2016-02-17 3:37 UTC (permalink / raw)
To: Vaishali Thakkar
Cc: Andrew Morton, mike.kravetz, hillf.zj, kirill.shutemov,
dave.hansen, paul.gortmaker, linux-mm, linux-kernel
On Wed, Feb 17, 2016 at 01:13:26AM +0530, Vaishali Thakkar wrote:
> Currently incorrect default hugepage pool size is reported by proc
> nr_hugepages when number of pages for the default huge page size is
> specified twice.
>
> When multiple huge page sizes are supported, /proc/sys/vm/nr_hugepages
> indicates the current number of pre-allocated huge pages of the default
> size. Basically /proc/sys/vm/nr_hugepages displays default_hstate->
> max_huge_pages and after boot time pre-allocation, max_huge_pages should
> equal the number of pre-allocated pages (nr_hugepages).
>
> Test case:
>
> Note that this is specific to x86 architecture.
>
> Boot the kernel with command line option 'default_hugepagesz=1G
> hugepages=X hugepagesz=2M hugepages=Y hugepagesz=1G hugepages=Z'. After
> boot, 'cat /proc/sys/vm/nr_hugepages' and 'sysctl -a | grep hugepages'
> returns the value X. However, dmesg output shows that Z huge pages were
> pre-allocated.
>
> So, the root cause of the problem here is that the global variable
> default_hstate_max_huge_pages is set if a default huge page size is
> specified (directly or indirectly) on the command line. After the
> command line processing in hugetlb_init, if default_hstate_max_huge_pages
> is set, the value is assigned to default_hstae.max_huge_pages. However,
> default_hstate.max_huge_pages may have already been set based on the
> number of pre-allocated huge pages of default_hstate size.
>
> The solution to this problem is if hstate->max_huge_pages is already set
> then it should not set as a result of global max_huge_pages value.
> Basically if the value of the variable hugepages is set multiple times
> on a command line for a specific supported hugepagesize then proc layer
> should consider the last specified value.
>
> Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Looks good to me.
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> ---
> The patch contains one line over 80 characters as I think limiting that
> line to 80 characters makes code look bit ugly. But if anyone is having
> issue with that then I am fine with limiting it to 80 chracters.
> ---
> mm/hugetlb.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 06ae13e..01f2b48 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2630,8 +2630,10 @@ static int __init hugetlb_init(void)
> hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
> }
> default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
> - if (default_hstate_max_huge_pages)
> - default_hstate.max_huge_pages = default_hstate_max_huge_pages;
> + if (default_hstate_max_huge_pages) {
> + if (!default_hstate.max_huge_pages)
> + default_hstate.max_huge_pages = default_hstate_max_huge_pages;
> + }
>
> hugetlb_init_hstates();
> gather_bootmem_prealloc();
> --
> 2.1.4
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/hugetlb: Fix incorrect proc nr_hugepages value
2016-02-16 19:43 [PATCH] mm/hugetlb: Fix incorrect proc nr_hugepages value Vaishali Thakkar
2016-02-17 3:37 ` Naoya Horiguchi
@ 2016-02-17 9:59 ` Kirill A. Shutemov
2016-02-17 10:30 ` Vaishali Thakkar
1 sibling, 1 reply; 4+ messages in thread
From: Kirill A. Shutemov @ 2016-02-17 9:59 UTC (permalink / raw)
To: Vaishali Thakkar
Cc: Andrew Morton, n-horiguchi, mike.kravetz, hillf.zj,
kirill.shutemov, dave.hansen, paul.gortmaker, linux-mm,
linux-kernel
On Wed, Feb 17, 2016 at 01:13:26AM +0530, Vaishali Thakkar wrote:
> Currently incorrect default hugepage pool size is reported by proc
> nr_hugepages when number of pages for the default huge page size is
> specified twice.
>
> When multiple huge page sizes are supported, /proc/sys/vm/nr_hugepages
> indicates the current number of pre-allocated huge pages of the default
> size. Basically /proc/sys/vm/nr_hugepages displays default_hstate->
> max_huge_pages and after boot time pre-allocation, max_huge_pages should
> equal the number of pre-allocated pages (nr_hugepages).
>
> Test case:
>
> Note that this is specific to x86 architecture.
>
> Boot the kernel with command line option 'default_hugepagesz=1G
> hugepages=X hugepagesz=2M hugepages=Y hugepagesz=1G hugepages=Z'. After
> boot, 'cat /proc/sys/vm/nr_hugepages' and 'sysctl -a | grep hugepages'
> returns the value X. However, dmesg output shows that Z huge pages were
> pre-allocated.
>
> So, the root cause of the problem here is that the global variable
> default_hstate_max_huge_pages is set if a default huge page size is
> specified (directly or indirectly) on the command line. After the
> command line processing in hugetlb_init, if default_hstate_max_huge_pages
> is set, the value is assigned to default_hstae.max_huge_pages. However,
> default_hstate.max_huge_pages may have already been set based on the
> number of pre-allocated huge pages of default_hstate size.
>
> The solution to this problem is if hstate->max_huge_pages is already set
> then it should not set as a result of global max_huge_pages value.
> Basically if the value of the variable hugepages is set multiple times
> on a command line for a specific supported hugepagesize then proc layer
> should consider the last specified value.
>
> Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
> ---
> The patch contains one line over 80 characters as I think limiting that
> line to 80 characters makes code look bit ugly. But if anyone is having
> issue with that then I am fine with limiting it to 80 chracters.
What about this?
if (default_hstate_max_huge_pages && !default_hstate.max_huge_pages)
default_hstate.max_huge_pages = default_hstate_max_huge_pages;
> ---
> mm/hugetlb.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 06ae13e..01f2b48 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2630,8 +2630,10 @@ static int __init hugetlb_init(void)
> hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
> }
> default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
> - if (default_hstate_max_huge_pages)
> - default_hstate.max_huge_pages = default_hstate_max_huge_pages;
> + if (default_hstate_max_huge_pages) {
> + if (!default_hstate.max_huge_pages)
> + default_hstate.max_huge_pages = default_hstate_max_huge_pages;
> + }
>
> hugetlb_init_hstates();
> gather_bootmem_prealloc();
> --
> 2.1.4
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
Kirill A. Shutemov
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/hugetlb: Fix incorrect proc nr_hugepages value
2016-02-17 9:59 ` Kirill A. Shutemov
@ 2016-02-17 10:30 ` Vaishali Thakkar
0 siblings, 0 replies; 4+ messages in thread
From: Vaishali Thakkar @ 2016-02-17 10:30 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: Andrew Morton, n-horiguchi, mike.kravetz, hillf.zj,
kirill.shutemov, dave.hansen, paul.gortmaker, linux-mm,
linux-kernel
On Wednesday 17 February 2016 03:29 PM, Kirill A. Shutemov wrote:
> On Wed, Feb 17, 2016 at 01:13:26AM +0530, Vaishali Thakkar wrote:
>> Currently incorrect default hugepage pool size is reported by proc
>> nr_hugepages when number of pages for the default huge page size is
>> specified twice.
>>
>> When multiple huge page sizes are supported, /proc/sys/vm/nr_hugepages
>> indicates the current number of pre-allocated huge pages of the default
>> size. Basically /proc/sys/vm/nr_hugepages displays default_hstate->
>> max_huge_pages and after boot time pre-allocation, max_huge_pages should
>> equal the number of pre-allocated pages (nr_hugepages).
>>
>> Test case:
>>
>> Note that this is specific to x86 architecture.
>>
>> Boot the kernel with command line option 'default_hugepagesz=1G
>> hugepages=X hugepagesz=2M hugepages=Y hugepagesz=1G hugepages=Z'. After
>> boot, 'cat /proc/sys/vm/nr_hugepages' and 'sysctl -a | grep hugepages'
>> returns the value X. However, dmesg output shows that Z huge pages were
>> pre-allocated.
>>
>> So, the root cause of the problem here is that the global variable
>> default_hstate_max_huge_pages is set if a default huge page size is
>> specified (directly or indirectly) on the command line. After the
>> command line processing in hugetlb_init, if default_hstate_max_huge_pages
>> is set, the value is assigned to default_hstae.max_huge_pages. However,
>> default_hstate.max_huge_pages may have already been set based on the
>> number of pre-allocated huge pages of default_hstate size.
>>
>> The solution to this problem is if hstate->max_huge_pages is already set
>> then it should not set as a result of global max_huge_pages value.
>> Basically if the value of the variable hugepages is set multiple times
>> on a command line for a specific supported hugepagesize then proc layer
>> should consider the last specified value.
>>
>> Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
>> ---
>> The patch contains one line over 80 characters as I think limiting that
>> line to 80 characters makes code look bit ugly. But if anyone is having
>> issue with that then I am fine with limiting it to 80 chracters.
> What about this?
>
> if (default_hstate_max_huge_pages && !default_hstate.max_huge_pages)
> default_hstate.max_huge_pages = default_hstate_max_huge_pages;
Yes, it does the same thing. I thought about it. But to me somehow it looks
hard to read. So, personally I don't prefer it.
Do you want me to change this?
>> ---
>> mm/hugetlb.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>> index 06ae13e..01f2b48 100644
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -2630,8 +2630,10 @@ static int __init hugetlb_init(void)
>> hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
>> }
>> default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
>> - if (default_hstate_max_huge_pages)
>> - default_hstate.max_huge_pages = default_hstate_max_huge_pages;
>> + if (default_hstate_max_huge_pages) {
>> + if (!default_hstate.max_huge_pages)
>> + default_hstate.max_huge_pages = default_hstate_max_huge_pages;
>> + }
>>
>> hugetlb_init_hstates();
>> gather_bootmem_prealloc();
>> --
>> 2.1.4
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@kvack.org. For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
>> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
Vaishali
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-02-17 10:31 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-02-16 19:43 [PATCH] mm/hugetlb: Fix incorrect proc nr_hugepages value Vaishali Thakkar
2016-02-17 3:37 ` Naoya Horiguchi
2016-02-17 9:59 ` Kirill A. Shutemov
2016-02-17 10:30 ` Vaishali Thakkar
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).