From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e1.ny.us.ibm.com (e1.ny.us.ibm.com [32.97.182.141]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e1.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id E9CC51007D8 for ; Thu, 14 Apr 2011 08:33:16 +1000 (EST) Received: from d01dlp02.pok.ibm.com (d01dlp02.pok.ibm.com [9.56.224.85]) by e1.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p3DMMgJ2032447 for ; Wed, 13 Apr 2011 18:22:42 -0400 Received: from d01relay05.pok.ibm.com (d01relay05.pok.ibm.com [9.56.227.237]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 7FAA86E803C for ; Wed, 13 Apr 2011 18:33:13 -0400 (EDT) Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay05.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p3DMXDUe202856 for ; Wed, 13 Apr 2011 18:33:13 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p3DMXCc1029743 for ; Wed, 13 Apr 2011 18:33:13 -0400 From: Nishanth Aravamudan To: Ben Herrenschmidt Subject: [PATCH v2] powerpc: align DTL buffer to AMS boundary Date: Wed, 13 Apr 2011 15:33:08 -0700 Message-Id: <1302733988-23037-1-git-send-email-nacc@us.ibm.com> In-Reply-To: <1302706373-11653-1-git-send-email-nacc@us.ibm.com> References: <1302706373-11653-1-git-send-email-nacc@us.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras , Anton Blanchard List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , PAPR specifies that DTL buffers can not cross AMS environments (aka CMO in the PAPR) and can not cross a memory entitlement granule boundary (4k). This is found in section 14.11.3.2 H_REGISTER_VPA of the PAPR. kmalloc does not guarantee an alignment of the allocation, though, beyond 8 bytes (at least in my understanding). Over-allocate and align the resulting address. Tested both with and without AMS on a p7 partition. --- Change from v1: removed extraneous #include. Note, I initially put this in a firmware check if-block, but we have also seen some issues with alignment with non-AMS partitions. The wasted memory is unfortunate, though. Cc: Paul Mackerras Cc: Anton Blanchard Cc: linuxppc-dev@lists.ozlabs.org arch/powerpc/platforms/pseries/setup.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 0007241..a67be48 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -293,14 +293,15 @@ static int alloc_dispatch_logs(void) for_each_possible_cpu(cpu) { pp = &paca[cpu]; - dtl = kmalloc_node(DISPATCH_LOG_BYTES, GFP_KERNEL, - cpu_to_node(cpu)); + dtl = kmalloc_node(DISPATCH_LOG_BYTES + DISPATCH_LOG_BYTES - 1, + GFP_KERNEL, cpu_to_node(cpu)); if (!dtl) { pr_warn("Failed to allocate dispatch trace log for cpu %d\n", cpu); pr_warn("Stolen time statistics will be unreliable\n"); break; } + dtl = PTR_ALIGN(dtl, DISPATCH_LOG_BYTES); pp->dtl_ridx = 0; pp->dispatch_log = dtl; -- 1.7.4.1