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From: Jan Beulich <jbeulich@suse.com>
To: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Cc: George Dunlap <george.dunlap@citrix.com>,
	Julien Grall <julien@xen.org>,
	Stefano Stabellini <sstabellini@kernel.org>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Ping: [PATCH v2 8/8] Arm/optee: don't open-code xzalloc_flex_struct()
Date: Mon, 3 May 2021 15:53:16 +0200	[thread overview]
Message-ID: <d61a2123-b501-15d6-e2c1-f18aa4790b46@suse.com> (raw)
In-Reply-To: <5fa042ac-9609-eab7-b14d-a59782ef4141@suse.com>

Volodymyr,

On 21.04.2021 16:59, Jan Beulich wrote:
> The current use of xzalloc_bytes() in optee is nearly an open-coded
> version  of xzalloc_flex_struct(), which was introduced after the driver
> was merged.
> 
> The main difference is xzalloc_bytes() will also force the allocation to
> be SMP_CACHE_BYTES aligned and therefore avoid sharing the cache line.
> While sharing the cache line can have an impact on the performance, this
> is also true for most of the other users of x*alloc(), x*alloc_array(),
> and x*alloc_flex_struct(). So if we want to prevent sharing cache lines,
> arranging for this should be done in the allocator itself.
> 
> In this case, we don't need stricter alignment than what the allocator 
> provides. Hence replace the call to xzalloc_bytes() with one of
> xzalloc_flex_struct().
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> Signed-off-by: Julien Grall <julien@xen.org>
> ---
> v2: Use commit message very close to what was suggested by Julien.

I realize I forgot to Cc you on the v2 submission, but I didn't hear
back on v1 from you either. May I ask for an ack or otherwise?

Thanks, Jan

> --- a/xen/arch/arm/tee/optee.c
> +++ b/xen/arch/arm/tee/optee.c
> @@ -529,8 +529,7 @@ static struct optee_shm_buf *allocate_op
>      while ( unlikely(old != atomic_cmpxchg(&ctx->optee_shm_buf_pages,
>                                             old, new)) );
>  
> -    optee_shm_buf = xzalloc_bytes(sizeof(struct optee_shm_buf) +
> -                                  pages_cnt * sizeof(struct page *));
> +    optee_shm_buf = xzalloc_flex_struct(struct optee_shm_buf, pages, pages_cnt);
>      if ( !optee_shm_buf )
>      {
>          err_code = -ENOMEM;
> 
> 



  reply	other threads:[~2021-05-03 13:53 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-21 14:54 [PATCH v2 0/8] assorted replacement of x[mz]alloc_bytes() Jan Beulich
2021-04-21 14:56 ` [PATCH v2 1/8] x86/MCE: avoid effectively open-coding xmalloc_array() Jan Beulich
2021-04-21 14:56 ` [PATCH v2 2/8] x86/HVM: " Jan Beulich
2021-04-21 14:57 ` [PATCH v2 3/8] x86/oprofile: " Jan Beulich
2021-04-21 14:57 ` [PATCH v2 4/8] x86/IRQ: avoid over-alignment in alloc_pirq_struct() Jan Beulich
2021-04-21 14:58 ` [PATCH v2 5/8] EFI/runtime: avoid effectively open-coding x{m,z}alloc_array() Jan Beulich
2021-04-21 14:58 ` [PATCH v2 6/8] kexec: avoid effectively open-coding xzalloc_flex_struct() Jan Beulich
2021-04-21 14:59 ` [PATCH v2 7/8] video/lfb: avoid effectively open-coding xzalloc_array() Jan Beulich
2021-04-21 14:59 ` [PATCH v2 8/8] Arm/optee: don't open-code xzalloc_flex_struct() Jan Beulich
2021-05-03 13:53   ` Jan Beulich [this message]
2021-05-04 23:49     ` Ping: " Volodymyr Babchuk
2021-04-21 15:23 ` [PATCH v2 0/8] assorted replacement of x[mz]alloc_bytes() Andrew Cooper
2021-04-21 15:32   ` Jan Beulich
2021-04-23  9:44   ` Jan Beulich

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