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From: Laurentiu Tudor <b10716@freescale.com>
To: Michael Neuling <mikey@neuling.org>, <greg@kroah.com>,
	<arnd@arndb.de>, <mpe@ellerman.id.au>, <benh@kernel.crashing.org>
Cc: <cbe-oss-dev@lists.ozlabs.org>, <imunsie@au.ibm.com>,
	<linux-kernel@vger.kernel.org>, <linuxppc-dev@ozlabs.org>,
	<jk@ozlabs.org>, <anton@samba.org>
Subject: Re: [PATCH 03/15] powerpc/msi: Improve IRQ bitmap allocator
Date: Mon, 22 Sep 2014 11:29:10 +0300	[thread overview]
Message-ID: <541FDDD6.9040009@freescale.com> (raw)
In-Reply-To: <1411028820-29933-4-git-send-email-mikey@neuling.org>

Hi Michael,

Minor comment inline.

On 09/18/2014 11:26 AM, Michael Neuling wrote:
> From: Ian Munsie <imunsie@au1.ibm.com>
> 
> Currently msi_bitmap_alloc_hwirqs() will round up any IRQ allocation requests
> to the nearest power of 2.  eg. ask for 5 IRQs and you'll get 8.  This wastes a
> lot of IRQs which can be a scarce resource.
> 
> For cxl we can require multiple IRQs for every contexts that is attached to the
> accelerator.  For AFU directed accelerators, there may be 1000s of contexts
> attached, hence we can easily run out of IRQs, especially if we are needlessly
> wasting them.
> 
> This changes the msi_bitmap_alloc_hwirqs() to allocate only the required number
> of IRQs, hence avoiding this wastage.
> 
> Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
> Signed-off-by: Michael Neuling <mikey@neuling.org>
> ---
>  arch/powerpc/sysdev/msi_bitmap.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/sysdev/msi_bitmap.c b/arch/powerpc/sysdev/msi_bitmap.c
> index 2ff6302..e001559 100644
> --- a/arch/powerpc/sysdev/msi_bitmap.c
> +++ b/arch/powerpc/sysdev/msi_bitmap.c
> @@ -24,28 +24,36 @@ int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
>  	 * This is fast, but stricter than we need. We might want to add
>  	 * a fallback routine which does a linear search with no alignment.
>  	 */

Is this comment still relevant (especially the part mentioning "fast")?

---
Best Regards, Laurentiu

WARNING: multiple messages have this Message-ID (diff)
From: Laurentiu Tudor <b10716@freescale.com>
To: Michael Neuling <mikey@neuling.org>, <greg@kroah.com>,
	<arnd@arndb.de>, <mpe@ellerman.id.au>, <benh@kernel.crashing.org>
Cc: cbe-oss-dev@lists.ozlabs.org, imunsie@au.ibm.com,
	linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
	anton@samba.org, jk@ozlabs.org
Subject: Re: [PATCH 03/15] powerpc/msi: Improve IRQ bitmap allocator
Date: Mon, 22 Sep 2014 11:29:10 +0300	[thread overview]
Message-ID: <541FDDD6.9040009@freescale.com> (raw)
In-Reply-To: <1411028820-29933-4-git-send-email-mikey@neuling.org>

Hi Michael,

Minor comment inline.

On 09/18/2014 11:26 AM, Michael Neuling wrote:
> From: Ian Munsie <imunsie@au1.ibm.com>
> 
> Currently msi_bitmap_alloc_hwirqs() will round up any IRQ allocation requests
> to the nearest power of 2.  eg. ask for 5 IRQs and you'll get 8.  This wastes a
> lot of IRQs which can be a scarce resource.
> 
> For cxl we can require multiple IRQs for every contexts that is attached to the
> accelerator.  For AFU directed accelerators, there may be 1000s of contexts
> attached, hence we can easily run out of IRQs, especially if we are needlessly
> wasting them.
> 
> This changes the msi_bitmap_alloc_hwirqs() to allocate only the required number
> of IRQs, hence avoiding this wastage.
> 
> Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
> Signed-off-by: Michael Neuling <mikey@neuling.org>
> ---
>  arch/powerpc/sysdev/msi_bitmap.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/sysdev/msi_bitmap.c b/arch/powerpc/sysdev/msi_bitmap.c
> index 2ff6302..e001559 100644
> --- a/arch/powerpc/sysdev/msi_bitmap.c
> +++ b/arch/powerpc/sysdev/msi_bitmap.c
> @@ -24,28 +24,36 @@ int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
>  	 * This is fast, but stricter than we need. We might want to add
>  	 * a fallback routine which does a linear search with no alignment.
>  	 */

Is this comment still relevant (especially the part mentioning "fast")?

---
Best Regards, Laurentiu

  parent reply	other threads:[~2014-09-22  8:46 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-18  8:26 [PATCH 0/15] POWER8 Coherent Accelerator device driver Michael Neuling
2014-09-18  8:26 ` Michael Neuling
2014-09-18  8:26 ` [PATCH 01/15] powerpc/cell: Move spu_handle_mm_fault() out of cell platform Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-18 10:00   ` Jeremy Kerr
2014-09-18 10:00     ` Jeremy Kerr
2014-09-18 23:26     ` Michael Neuling
2014-09-18 23:26       ` Michael Neuling
2014-09-26  3:57   ` Anton Blanchard
2014-09-26  3:57     ` Anton Blanchard
2014-09-18  8:26 ` [PATCH 02/15] powerpc/cell: Move data segment faulting code " Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-18 10:27   ` Jeremy Kerr
2014-09-18 10:27     ` Jeremy Kerr
2014-09-18 23:45     ` Michael Neuling
2014-09-18 23:45       ` Michael Neuling
2014-09-26  4:05   ` Anton Blanchard
2014-09-26  4:05     ` Anton Blanchard
2014-09-26 11:19     ` Michael Neuling
2014-09-26 11:19       ` Michael Neuling
2014-09-29  8:30   ` Aneesh Kumar K.V
2014-09-29  8:30     ` Aneesh Kumar K.V
2014-09-30  4:40     ` Michael Neuling
2014-09-30  4:40       ` Michael Neuling
2014-09-18  8:26 ` [PATCH 03/15] powerpc/msi: Improve IRQ bitmap allocator Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-19 20:16   ` Scott Wood
2014-09-19 20:16     ` Scott Wood
2014-09-19 20:19     ` Scott Wood
2014-09-19 20:19       ` Scott Wood
2014-09-22  8:26       ` Laurentiu Tudor
2014-09-22  8:26         ` Laurentiu Tudor
2014-09-22 23:50         ` Scott Wood
2014-09-22 23:50           ` Scott Wood
2014-09-22  8:25     ` Laurentiu Tudor
2014-09-22  8:25       ` Laurentiu Tudor
2014-09-22  8:29   ` Laurentiu Tudor [this message]
2014-09-22  8:29     ` Laurentiu Tudor
2014-09-22 22:59     ` Michael Neuling
2014-09-22 22:59       ` Michael Neuling
2014-09-18  8:26 ` [PATCH 04/15] powerpc/mm: Export mmu_kernel_ssize and mmu_linear_psize Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-18  8:26 ` [PATCH 05/15] powerpc/powernv: Split out set MSI IRQ chip code Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-19  6:54   ` Gavin Shan
2014-09-19  6:54     ` Gavin Shan
2014-09-22  4:31     ` Michael Neuling
2014-09-22  4:31       ` Michael Neuling
2014-09-18  8:26 ` [PATCH 06/15] cxl: Add new header for call backs and structs Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-18  8:26 ` [PATCH 07/15] powerpc/powerpc: Add new PCIe functions for allocating cxl interrupts Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-19  7:09   ` Gavin Shan
2014-09-19  7:09     ` Gavin Shan
2014-09-22  5:01     ` Michael Neuling
2014-09-22  5:01       ` Michael Neuling
2014-09-18  8:26 ` [PATCH 08/15] powerpc/mm: Add new hash_page_mm() Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-29  8:50   ` Aneesh Kumar K.V
2014-09-29  8:50     ` Aneesh Kumar K.V
     [not found]     ` <1412054407.1733.77.camel@ale.ozlabs.ibm.com>
2014-09-30  6:13       ` Michael Neuling
2014-09-30  6:13         ` Michael Neuling
2014-09-18  8:26 ` [PATCH 09/15] powerpc/opal: Add PHB to cxl mode call Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-26  4:35   ` Anton Blanchard
2014-09-26  4:35     ` Anton Blanchard
2014-09-18  8:26 ` [PATCH 10/15] powerpc/mm: Add hooks for cxl Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-26  4:33   ` Anton Blanchard
2014-09-26  4:33     ` Anton Blanchard
2014-09-26 11:33     ` Michael Neuling
2014-09-26 11:33       ` Michael Neuling
2014-09-26 13:24       ` Anton Blanchard
2014-09-26 13:24         ` Anton Blanchard
2014-09-29  9:10   ` Aneesh Kumar K.V
2014-09-29  9:10     ` Aneesh Kumar K.V
2014-09-18  8:26 ` [PATCH 11/15] cxl: Add base builtin support Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-18  8:26 ` [PATCH 12/15] cxl: Driver code for powernv PCIe based cards for userspace access Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-18  8:26 ` [PATCH 13/15] cxl: Userspace header file Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-18  8:26 ` [PATCH 14/15] cxl: Add driver to Kbuild and Makefiles Michael Neuling
2014-09-18  8:26   ` Michael Neuling
2014-09-18  8:27 ` [PATCH 15/15] cxl: Add documentation for userspace APIs Michael Neuling
2014-09-18  8:27   ` Michael Neuling

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