From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755865AbaIRI1Z (ORCPT ); Thu, 18 Sep 2014 04:27:25 -0400 Received: from ozlabs.org ([103.22.144.67]:36948 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754660AbaIRI1R (ORCPT ); Thu, 18 Sep 2014 04:27:17 -0400 From: Michael Neuling To: greg@kroah.com, arnd@arndb.de, mpe@ellerman.id.au, benh@kernel.crashing.org Cc: mikey@neuling.org, anton@samba.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, jk@ozlabs.org, imunsie@au.ibm.com, cbe-oss-dev@lists.ozlabs.org Subject: [PATCH 03/15] powerpc/msi: Improve IRQ bitmap allocator Date: Thu, 18 Sep 2014 18:26:48 +1000 Message-Id: <1411028820-29933-4-git-send-email-mikey@neuling.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1411028820-29933-1-git-send-email-mikey@neuling.org> References: <1411028820-29933-1-git-send-email-mikey@neuling.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ian Munsie 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 Signed-off-by: Michael Neuling --- 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. */ - offset = bitmap_find_free_region(bmp->bitmap, bmp->irq_count, order); + offset = bitmap_find_next_zero_area(bmp->bitmap, bmp->irq_count, 0, + num, (1 << order) - 1); + if (offset > bmp->irq_count) + goto err; + bitmap_set(bmp->bitmap, offset, num); spin_unlock_irqrestore(&bmp->lock, flags); pr_debug("msi_bitmap: allocated 0x%x (2^%d) at offset 0x%x\n", num, order, offset); return offset; +err: + spin_unlock_irqrestore(&bmp->lock, flags); + return -ENOMEM; } +EXPORT_SYMBOL(msi_bitmap_alloc_hwirqs); void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset, unsigned int num) { unsigned long flags; - int order = get_count_order(num); - pr_debug("msi_bitmap: freeing 0x%x (2^%d) at offset 0x%x\n", - num, order, offset); + pr_debug("msi_bitmap: freeing 0x%x at offset 0x%x\n", + num, offset); spin_lock_irqsave(&bmp->lock, flags); - bitmap_release_region(bmp->bitmap, offset, order); + bitmap_clear(bmp->bitmap, offset, num); spin_unlock_irqrestore(&bmp->lock, flags); } +EXPORT_SYMBOL(msi_bitmap_free_hwirqs); void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq) { -- 1.9.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id AA6E01A0931 for ; Thu, 18 Sep 2014 18:27:16 +1000 (EST) From: Michael Neuling To: greg@kroah.com, arnd@arndb.de, mpe@ellerman.id.au, benh@kernel.crashing.org Subject: [PATCH 03/15] powerpc/msi: Improve IRQ bitmap allocator Date: Thu, 18 Sep 2014 18:26:48 +1000 Message-Id: <1411028820-29933-4-git-send-email-mikey@neuling.org> In-Reply-To: <1411028820-29933-1-git-send-email-mikey@neuling.org> References: <1411028820-29933-1-git-send-email-mikey@neuling.org> Cc: cbe-oss-dev@lists.ozlabs.org, mikey@neuling.org, imunsie@au.ibm.com, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, jk@ozlabs.org, anton@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Ian Munsie 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 Signed-off-by: Michael Neuling --- 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. */ - offset = bitmap_find_free_region(bmp->bitmap, bmp->irq_count, order); + offset = bitmap_find_next_zero_area(bmp->bitmap, bmp->irq_count, 0, + num, (1 << order) - 1); + if (offset > bmp->irq_count) + goto err; + bitmap_set(bmp->bitmap, offset, num); spin_unlock_irqrestore(&bmp->lock, flags); pr_debug("msi_bitmap: allocated 0x%x (2^%d) at offset 0x%x\n", num, order, offset); return offset; +err: + spin_unlock_irqrestore(&bmp->lock, flags); + return -ENOMEM; } +EXPORT_SYMBOL(msi_bitmap_alloc_hwirqs); void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset, unsigned int num) { unsigned long flags; - int order = get_count_order(num); - pr_debug("msi_bitmap: freeing 0x%x (2^%d) at offset 0x%x\n", - num, order, offset); + pr_debug("msi_bitmap: freeing 0x%x at offset 0x%x\n", + num, offset); spin_lock_irqsave(&bmp->lock, flags); - bitmap_release_region(bmp->bitmap, offset, order); + bitmap_clear(bmp->bitmap, offset, num); spin_unlock_irqrestore(&bmp->lock, flags); } +EXPORT_SYMBOL(msi_bitmap_free_hwirqs); void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq) { -- 1.9.1