From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from panicking.kicks-ass.org (unknown [77.224.194.88]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 391C0DDED1 for ; Thu, 23 Apr 2009 02:01:49 +1000 (EST) Message-ID: <49EF254A.6020106@evidence.eu.com> Date: Wed, 22 Apr 2009 16:10:18 +0200 From: michael MIME-Version: 1.0 To: Stefan Roscher Subject: Re: [PATCH 1/3] IB/ehca: Replace vmalloc with kmalloc References: <200904211716.45245.ossrosch@linux.vnet.ibm.com> <200904221602.29028.ossrosch@linux.vnet.ibm.com> In-Reply-To: <200904221602.29028.ossrosch@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: Roland Dreier , fenkes@de.ibm.com, LKML , OF-EWG , LinuxPPC-Dev , raisch@de.ibm.com, alexschm@de.ibm.com, stefan.roscher@de.ibm.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, Stefan Roscher wrote: > In case of large queue pairs there is the possibillity of allocation failures > due to memory fragmentationo with kmalloc().To ensure the memory is allocated even > if kmalloc() can not find chunks which are big enough, we try to allocate the memory > with vmalloc(). > > Signed-off-by: Stefan Roscher > --- > > On Tuesday 21 April 2009 07:34:30 pm Roland Dreier wrote: > >> > + queue->queue_pages = kmalloc(nr_of_pages * sizeof(void *), GFP_KERNEL); >> >> How big might this buffer be? Any chance of allocation failure due to >> memory fragmentation? >> >> - R. >> > Hey Roland, > yes you are right and here is the patch to circumvent the described problem. > It will apply on top of the patchset. > regards Stefan > > I don't take the point, if it is not import use the vmalloc. Why you try with a kmalloc alloc first? and why do not use kzalloc? > > drivers/infiniband/hw/ehca/ipz_pt_fn.c | 17 +++++++++++++---- > 1 files changed, 13 insertions(+), 4 deletions(-) > > diff --git a/drivers/infiniband/hw/ehca/ipz_pt_fn.c b/drivers/infiniband/hw/ehca/ipz_pt_fn.c > index a260559..1227c59 100644 > --- a/drivers/infiniband/hw/ehca/ipz_pt_fn.c > +++ b/drivers/infiniband/hw/ehca/ipz_pt_fn.c > @@ -222,8 +222,11 @@ int ipz_queue_ctor(struct ehca_pd *pd, struct ipz_queue *queue, > /* allocate queue page pointers */ > queue->queue_pages = kmalloc(nr_of_pages * sizeof(void *), GFP_KERNEL); > if (!queue->queue_pages) { > - ehca_gen_err("Couldn't allocate queue page list"); > - return 0; > + queue->queue_pages = vmalloc(nr_of_pages * sizeof(void *)); > + if (!queue->queue_pages) { > + ehca_gen_err("Couldn't allocate queue page list"); > + return 0; > + } > } > memset(queue->queue_pages, 0, nr_of_pages * sizeof(void *)); > > @@ -240,7 +243,10 @@ int ipz_queue_ctor(struct ehca_pd *pd, struct ipz_queue *queue, > ipz_queue_ctor_exit0: > ehca_gen_err("Couldn't alloc pages queue=%p " > "nr_of_pages=%x", queue, nr_of_pages); > - kfree(queue->queue_pages); > + if (is_vmalloc_addr(queue->queue_pages)) > + vfree(queue->queue_pages); > + else > + kfree(queue->queue_pages); > > return 0; > } > @@ -262,7 +268,10 @@ int ipz_queue_dtor(struct ehca_pd *pd, struct ipz_queue *queue) > free_page((unsigned long)queue->queue_pages[i]); > } > > - kfree(queue->queue_pages); > + if (is_vmalloc_addr(queue->queue_pages)) > + vfree(queue->queue_pages); > + else > + kfree(queue->queue_pages); > > return 1; > } > Regards Michael