diff mbox series

[net-next] sock: make SKB_FRAG_PAGE_ORDER equal to PAGE_ALLOC_COSTLY_ORDER

Message ID 20241217105659.2215649-1-yajun.deng@linux.dev (mailing list archive)
State Rejected
Delegated to: Netdev Maintainers
Headers show
Series [net-next] sock: make SKB_FRAG_PAGE_ORDER equal to PAGE_ALLOC_COSTLY_ORDER | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 15 this patch: 15
netdev/build_tools success Errors and warnings before: 0 (+23) this patch: 0 (+23)
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 16422 this patch: 16422
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 2596 this patch: 2596
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 17 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 13 this patch: 13
netdev/source_inline success Was 0 now: 0
netdev/contest fail net-next-2024-12-17--21-00 (tests: 883)

Commit Message

Yajun Deng Dec. 17, 2024, 10:56 a.m. UTC 
The SKB_FRAG_PAGE_ORDER will be 3 if PAGE_SIZE is 4096, and less than 3
if it is not. So it will increase the number of memory allocations if
PAGE_SIZE is greater than 4096.

alloc_pages() only relates to the order, if an order is less than or equal
to PAGE_ALLOC_COSTLY_ORDER, it will get the page from rmqueue_pcplist() in
rmqueue(). So there's no need for the order to be less than
PAGE_ALLOC_COSTLY_ORDER.

To decrease the number of memory allocations, make SKB_FRAG_PAGE_ORDER
equal to PAGE_ALLOC_COSTLY_ORDER even if PAGE_SIZE isn't 4096.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
 include/net/sock.h | 2 +-
 net/core/sock.c    | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

Comments

Eric Dumazet Dec. 17, 2024, 11:09 a.m. UTC | #1 
On Tue, Dec 17, 2024 at 11:56 AM Yajun Deng <yajun.deng@linux.dev> wrote:
>
> The SKB_FRAG_PAGE_ORDER will be 3 if PAGE_SIZE is 4096, and less than 3
> if it is not. So it will increase the number of memory allocations if
> PAGE_SIZE is greater than 4096.
>
> alloc_pages() only relates to the order, if an order is less than or equal
> to PAGE_ALLOC_COSTLY_ORDER, it will get the page from rmqueue_pcplist() in
> rmqueue(). So there's no need for the order to be less than
> PAGE_ALLOC_COSTLY_ORDER.
>
> To decrease the number of memory allocations, make SKB_FRAG_PAGE_ORDER
> equal to PAGE_ALLOC_COSTLY_ORDER even if PAGE_SIZE isn't 4096.
>
> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> ---
>  include/net/sock.h | 2 +-
>  net/core/sock.c    | 3 +--
>  2 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/include/net/sock.h b/include/net/sock.h
> index 7464e9f9f47c..a33645226577 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -2853,7 +2853,7 @@ extern __u32 sysctl_rmem_max;
>  extern __u32 sysctl_wmem_default;
>  extern __u32 sysctl_rmem_default;
>
> -#define SKB_FRAG_PAGE_ORDER    get_order(32768)

We do not want to allow some programs to work on arches with 64K page
sizes, and not work on 4K page sizes.

Please post your precise use case.
kernel test robot Dec. 20, 2024, 1:42 p.m. UTC | #2 
Hi Yajun,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Yajun-Deng/sock-make-SKB_FRAG_PAGE_ORDER-equal-to-PAGE_ALLOC_COSTLY_ORDER/20241217-185748
base:   net-next/main
patch link:    https://lore.kernel.org/r/20241217105659.2215649-1-yajun.deng%40linux.dev
patch subject: [PATCH net-next] sock: make SKB_FRAG_PAGE_ORDER equal to PAGE_ALLOC_COSTLY_ORDER
config: openrisc-defconfig (https://download.01.org/0day-ci/archive/20241220/202412202122.04V0tnNx-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241220/202412202122.04V0tnNx-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202412202122.04V0tnNx-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from arch/openrisc/include/asm/page.h:18,
                    from arch/openrisc/include/asm/processor.h:19,
                    from arch/openrisc/include/asm/thread_info.h:22,
                    from include/linux/thread_info.h:60,
                    from include/asm-generic/preempt.h:5,
                    from ./arch/openrisc/include/generated/asm/preempt.h:1,
                    from include/linux/preempt.h:79,
                    from include/linux/spinlock.h:56,
                    from include/linux/wait.h:9,
                    from include/linux/wait_bit.h:8,
                    from include/linux/fs.h:6,
                    from include/linux/highmem.h:5,
                    from include/linux/bvec.h:10,
                    from include/linux/skbuff.h:17,
                    from include/linux/ip.h:16,
                    from include/net/ip.h:22,
                    from include/linux/errqueue.h:6,
                    from net/core/sock.c:91:
   net/core/sock.c: In function 'skb_page_frag_refill':
>> include/vdso/page.h:15:25: warning: conversion from 'long unsigned int' to '__u16' {aka 'short unsigned int'} changes value from '65536' to '0' [-Woverflow]
      15 | #define PAGE_SIZE       (_AC(1,UL) << CONFIG_PAGE_SHIFT)
         |                         ^
   net/core/sock.c:3044:39: note: in expansion of macro 'PAGE_SIZE'
    3044 |                         pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
         |                                       ^~~~~~~~~


vim +15 include/vdso/page.h

efe8419ae78d65 Vincenzo Frascino 2024-10-14  14  
efe8419ae78d65 Vincenzo Frascino 2024-10-14 @15  #define PAGE_SIZE	(_AC(1,UL) << CONFIG_PAGE_SHIFT)
efe8419ae78d65 Vincenzo Frascino 2024-10-14  16
kernel test robot Dec. 21, 2024, 12:05 a.m. UTC | #3 
Hi Yajun,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Yajun-Deng/sock-make-SKB_FRAG_PAGE_ORDER-equal-to-PAGE_ALLOC_COSTLY_ORDER/20241217-185748
base:   net-next/main
patch link:    https://lore.kernel.org/r/20241217105659.2215649-1-yajun.deng%40linux.dev
patch subject: [PATCH net-next] sock: make SKB_FRAG_PAGE_ORDER equal to PAGE_ALLOC_COSTLY_ORDER
config: openrisc-randconfig-r122-20241220 (https://download.01.org/0day-ci/archive/20241221/202412210700.fAOJ9ocm-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.2.0
reproduce: (https://download.01.org/0day-ci/archive/20241221/202412210700.fAOJ9ocm-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202412210700.fAOJ9ocm-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   net/core/sock.c:2496:9: sparse: sparse: context imbalance in 'sk_clone_lock' - wrong count at exit
   net/core/sock.c:2500:6: sparse: sparse: context imbalance in 'sk_free_unlock_clone' - unexpected unlock
>> net/core/sock.c:3044:49: sparse: sparse: cast truncates bits from constant value (10000 becomes 0)

vim +3044 net/core/sock.c

5640f7685831e08 Eric Dumazet 2012-09-23  3013  
400dfd3ae899849 Eric Dumazet 2013-10-17  3014  /**
400dfd3ae899849 Eric Dumazet 2013-10-17  3015   * skb_page_frag_refill - check that a page_frag contains enough room
400dfd3ae899849 Eric Dumazet 2013-10-17  3016   * @sz: minimum size of the fragment we want to get
400dfd3ae899849 Eric Dumazet 2013-10-17  3017   * @pfrag: pointer to page_frag
82d5e2b8b466d5b Eric Dumazet 2014-09-08  3018   * @gfp: priority for memory allocation
400dfd3ae899849 Eric Dumazet 2013-10-17  3019   *
400dfd3ae899849 Eric Dumazet 2013-10-17  3020   * Note: While this allocator tries to use high order pages, there is
400dfd3ae899849 Eric Dumazet 2013-10-17  3021   * no guarantee that allocations succeed. Therefore, @sz MUST be
400dfd3ae899849 Eric Dumazet 2013-10-17  3022   * less or equal than PAGE_SIZE.
400dfd3ae899849 Eric Dumazet 2013-10-17  3023   */
d9b2938aabf757d Eric Dumazet 2014-08-27  3024  bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t gfp)
5640f7685831e08 Eric Dumazet 2012-09-23  3025  {
5640f7685831e08 Eric Dumazet 2012-09-23  3026  	if (pfrag->page) {
fe896d1878949ea Joonsoo Kim  2016-03-17  3027  		if (page_ref_count(pfrag->page) == 1) {
5640f7685831e08 Eric Dumazet 2012-09-23  3028  			pfrag->offset = 0;
5640f7685831e08 Eric Dumazet 2012-09-23  3029  			return true;
5640f7685831e08 Eric Dumazet 2012-09-23  3030  		}
400dfd3ae899849 Eric Dumazet 2013-10-17  3031  		if (pfrag->offset + sz <= pfrag->size)
5640f7685831e08 Eric Dumazet 2012-09-23  3032  			return true;
5640f7685831e08 Eric Dumazet 2012-09-23  3033  		put_page(pfrag->page);
5640f7685831e08 Eric Dumazet 2012-09-23  3034  	}
5640f7685831e08 Eric Dumazet 2012-09-23  3035  
5640f7685831e08 Eric Dumazet 2012-09-23  3036  	pfrag->offset = 0;
af87ed7a96a9372 Yajun Deng   2024-12-17  3037  	if (!static_branch_unlikely(&net_high_order_alloc_disable_key)) {
d0164adc89f6bb3 Mel Gorman   2015-11-06  3038  		/* Avoid direct reclaim but allow kswapd to wake */
d0164adc89f6bb3 Mel Gorman   2015-11-06  3039  		pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
d0164adc89f6bb3 Mel Gorman   2015-11-06  3040  					  __GFP_COMP | __GFP_NOWARN |
d0164adc89f6bb3 Mel Gorman   2015-11-06  3041  					  __GFP_NORETRY,
d9b2938aabf757d Eric Dumazet 2014-08-27  3042  					  SKB_FRAG_PAGE_ORDER);
d9b2938aabf757d Eric Dumazet 2014-08-27  3043  		if (likely(pfrag->page)) {
d9b2938aabf757d Eric Dumazet 2014-08-27 @3044  			pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
d9b2938aabf757d Eric Dumazet 2014-08-27  3045  			return true;
d9b2938aabf757d Eric Dumazet 2014-08-27  3046  		}
d9b2938aabf757d Eric Dumazet 2014-08-27  3047  	}
d9b2938aabf757d Eric Dumazet 2014-08-27  3048  	pfrag->page = alloc_page(gfp);
d9b2938aabf757d Eric Dumazet 2014-08-27  3049  	if (likely(pfrag->page)) {
d9b2938aabf757d Eric Dumazet 2014-08-27  3050  		pfrag->size = PAGE_SIZE;
5640f7685831e08 Eric Dumazet 2012-09-23  3051  		return true;
5640f7685831e08 Eric Dumazet 2012-09-23  3052  	}
400dfd3ae899849 Eric Dumazet 2013-10-17  3053  	return false;
400dfd3ae899849 Eric Dumazet 2013-10-17  3054  }
400dfd3ae899849 Eric Dumazet 2013-10-17  3055  EXPORT_SYMBOL(skb_page_frag_refill);
400dfd3ae899849 Eric Dumazet 2013-10-17  3056
diff mbox series

Patch

diff --git a/include/net/sock.h b/include/net/sock.h
index 7464e9f9f47c..a33645226577 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2853,7 +2853,7 @@  extern __u32 sysctl_rmem_max;
 extern __u32 sysctl_wmem_default;
 extern __u32 sysctl_rmem_default;
 
-#define SKB_FRAG_PAGE_ORDER	get_order(32768)
+#define SKB_FRAG_PAGE_ORDER	PAGE_ALLOC_COSTLY_ORDER
 DECLARE_STATIC_KEY_FALSE(net_high_order_alloc_disable_key);
 
 static inline int sk_get_wmem0(const struct sock *sk, const struct proto *proto)
diff --git a/net/core/sock.c b/net/core/sock.c
index 74729d20cd00..0db306f4216c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3014,8 +3014,7 @@  bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t gfp)
 	}
 
 	pfrag->offset = 0;
-	if (SKB_FRAG_PAGE_ORDER &&
-	    !static_branch_unlikely(&net_high_order_alloc_disable_key)) {
+	if (!static_branch_unlikely(&net_high_order_alloc_disable_key)) {
 		/* Avoid direct reclaim but allow kswapd to wake */
 		pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
 					  __GFP_COMP | __GFP_NOWARN |