[Devel] [PATCH RHEL7 COMMIT] net/sctp: Suppress high order allocation warning

[Konstantin Khorenko]

Please, disregard, dropped.

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 04/02/2018 05:34 PM, Konstantin Khorenko wrote:
> The commit is pushed to "branch-rh7-3.10.0-693.21.1.vz7.46.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
> after rh7-3.10.0-693.21.1.vz7.46.2
> ------>
> commit 2f98c3fcb08a028de56103d6251ebefd2f611d7f
> Author: Oleg Babin <obabin at virtuozzo.com>
> Date:   Mon Apr 2 17:34:38 2018 +0300
>
>     net/sctp: Suppress high order allocation warning
>
>     SCTP protocol allocates TCB on INIT and COOKIE ECHO chunks, those
>     chunks specify input and output stream count (can be up to 65535
>     each), so the size of TCB depends on these values and can include
>     up to 65535 * 2 * 2 bytes describing input/output streams (2 bytes
>     per each stream), i.e. up to seventh order.
>
>     As the chunks are handled in softirq context, allocation is made
>     with kmalloc() with GFP_ATOMIC flag, so we can't just replace
>     kmalloc() call with kvmalloc().
>
>     So it was decided to introduce our own flag __GFP_NOWARNHIGHORDER
>     and update warn_high_order() function accordingly so that we could
>     selectively suppress high order warnings which can not be fixed
>     right now without proper algorithm refactoring.
>
>     https://jira.sw.ru/browse/PSBM-82552
>     Signed-off-by: Oleg Babin <obabin at virtuozzo.com>
> ---
>  include/linux/gfp.h | 3 +++
>  mm/page_alloc.c     | 4 +++-
>  net/sctp/ssnmap.c   | 2 +-
>  3 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/gfp.h b/include/linux/gfp.h
> index ec5ae8aa1085..a6f000f3702a 100644
> --- a/include/linux/gfp.h
> +++ b/include/linux/gfp.h
> @@ -41,6 +41,7 @@ struct vm_area_struct;
>  #define ___GFP_NO_KSWAPD	0x400000u
>  #define ___GFP_OTHER_NODE	0x800000u
>  #define ___GFP_WRITE		0x1000000u
> +#define ___GFP_NOWARNHIGHORDER	0x2000000u
>  /* If the above are modified, __GFP_BITS_SHIFT may need updating */
>
>  /*
> @@ -98,6 +99,8 @@ struct vm_area_struct;
>  #define __GFP_NO_KSWAPD	((__force gfp_t)___GFP_NO_KSWAPD)
>  #define __GFP_OTHER_NODE ((__force gfp_t)___GFP_OTHER_NODE) /* On behalf of other node */
>  #define __GFP_WRITE	((__force gfp_t)___GFP_WRITE)	/* Allocator intends to dirty page */
> +#define __GFP_NOWARNHIGHORDER ((__force gfp_t)___GFP_NOWARNHIGHORDER) /* Don't warn
> +							 * on high order allocations */
>
>  /*
>   * This may seem redundant, but it's a way of annotating false positives vs.
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 15575b24a97c..8cc264c56fb2 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3184,6 +3184,8 @@ int proc_warn_high_order(struct ctl_table *table, int write,
>  	return ret;
>  }
>
> +#define ORDER_NOWARN_MASK (__GFP_NOWARN | __GFP_NOWARNHIGHORDER)
> +
>  static __always_inline void warn_high_order(int order, gfp_t gfp_mask)
>  {
>  	static atomic_t warn_count = ATOMIC_INIT(32);
> @@ -3191,7 +3193,7 @@ static __always_inline void warn_high_order(int order, gfp_t gfp_mask)
>  	if (static_key_false(&warn_high_order_key)) {
>  		int tmp_warn_order = smp_load_acquire(&warn_order);
>
> -		if (order >= tmp_warn_order && !(gfp_mask & __GFP_NOWARN))
> +		if (order >= tmp_warn_order && !(gfp_mask & ORDER_NOWARN_MASK))
>  			WARN(atomic_dec_if_positive(&warn_count) >= 0,
>  				"order %d >= %d, gfp 0x%x\n",
>  				order, tmp_warn_order, gfp_mask);
> diff --git a/net/sctp/ssnmap.c b/net/sctp/ssnmap.c
> index da8603523808..989e1e8b4569 100644
> --- a/net/sctp/ssnmap.c
> +++ b/net/sctp/ssnmap.c
> @@ -64,7 +64,7 @@ struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
>
>  	size = sctp_ssnmap_size(in, out);
>  	if (size <= KMALLOC_MAX_SIZE)
> -		retval = kmalloc(size, gfp);
> +		retval = kmalloc(size, gfp | __GFP_NOWARNHIGHORDER);
>  	else
>  		retval = (struct sctp_ssnmap *)
>  			  __get_free_pages(gfp, get_order(size));
> .
>