From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751137AbdAXPkm (ORCPT ); Tue, 24 Jan 2017 10:40:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54540 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750714AbdAXPkl (ORCPT ); Tue, 24 Jan 2017 10:40:41 -0500 Date: Tue, 24 Jan 2017 17:40:38 +0200 From: "Michael S. Tsirkin" To: Michal Hocko Cc: Andrew Morton , Vlastimil Babka , David Rientjes , Mel Gorman , Johannes Weiner , Al Viro , linux-mm@kvack.org, LKML , Michal Hocko Subject: Re: [PATCH 2/6] mm: support __GFP_REPEAT in kvmalloc_node for >=64kB Message-ID: <20170124173956-mutt-send-email-mst@kernel.org> References: <20170112153717.28943-1-mhocko@kernel.org> <20170112153717.28943-3-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170112153717.28943-3-mhocko@kernel.org> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 24 Jan 2017 15:40:41 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 12, 2017 at 04:37:13PM +0100, Michal Hocko wrote: > From: Michal Hocko > > vhost code uses __GFP_REPEAT when allocating vhost_virtqueue resp. > vhost_vsock because it would really like to prefer kmalloc to the > vmalloc fallback - see 23cc5a991c7a ("vhost-net: extend device > allocation to vmalloc") for more context. Michael Tsirkin has also > noted: > " > __GFP_REPEAT overhead is during allocation time. Using vmalloc means all > accesses are slowed down. Allocation is not on data path, accesses are. > " > > The similar applies to other vhost_kvzalloc users. > > Let's teach kvmalloc_node to handle __GFP_REPEAT properly. There are two > things to be careful about. First we should prevent from the OOM killer > and so have to involve __GFP_NORETRY by default and secondly override > __GFP_REPEAT for !costly order requests as the __GFP_REPEAT is ignored > for !costly orders. > > Supporting __GFP_REPEAT like semantic for !costly request is possible > it would require changes in the page allocator. This is out of scope of > this patch. > > This patch shouldn't introduce any functional change. > > Cc: "Michael S. Tsirkin" > Acked-by: Vlastimil Babka > Signed-off-by: Michal Hocko Assuming the new APIs are upstream I see no reason not to use them in vhost. For vhost bits: Acked-by: Michael S. Tsirkin > --- > drivers/vhost/net.c | 9 +++------ > drivers/vhost/vhost.c | 15 +++------------ > drivers/vhost/vsock.c | 9 +++------ > mm/util.c | 17 ++++++++++++++--- > 4 files changed, 23 insertions(+), 27 deletions(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index 5dc34653274a..105cd04c7414 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -797,12 +797,9 @@ static int vhost_net_open(struct inode *inode, struct file *f) > struct vhost_virtqueue **vqs; > int i; > > - n = kmalloc(sizeof *n, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); > - if (!n) { > - n = vmalloc(sizeof *n); > - if (!n) > - return -ENOMEM; > - } > + n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_REPEAT); > + if (!n) > + return -ENOMEM; > vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL); > if (!vqs) { > kvfree(n); > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index d6432603880c..d2bf8a41f55e 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -515,18 +515,9 @@ long vhost_dev_set_owner(struct vhost_dev *dev) > } > EXPORT_SYMBOL_GPL(vhost_dev_set_owner); > > -static void *vhost_kvzalloc(unsigned long size) > -{ > - void *n = kzalloc(size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); > - > - if (!n) > - n = vzalloc(size); > - return n; > -} > - > struct vhost_umem *vhost_dev_reset_owner_prepare(void) > { > - return vhost_kvzalloc(sizeof(struct vhost_umem)); > + return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL); > } > EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare); > > @@ -1190,7 +1181,7 @@ EXPORT_SYMBOL_GPL(vhost_vq_access_ok); > > static struct vhost_umem *vhost_umem_alloc(void) > { > - struct vhost_umem *umem = vhost_kvzalloc(sizeof(*umem)); > + struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL); > > if (!umem) > return NULL; > @@ -1216,7 +1207,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) > return -EOPNOTSUPP; > if (mem.nregions > max_mem_regions) > return -E2BIG; > - newmem = vhost_kvzalloc(size + mem.nregions * sizeof(*m->regions)); > + newmem = kvzalloc(size + mem.nregions * sizeof(*m->regions), GFP_KERNEL); > if (!newmem) > return -ENOMEM; > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > index bbbf588540ed..7e0159867553 100644 > --- a/drivers/vhost/vsock.c > +++ b/drivers/vhost/vsock.c > @@ -455,12 +455,9 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file) > /* This struct is large and allocation could fail, fall back to vmalloc > * if there is no other way. > */ > - vsock = kzalloc(sizeof(*vsock), GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); > - if (!vsock) { > - vsock = vmalloc(sizeof(*vsock)); > - if (!vsock) > - return -ENOMEM; > - } > + vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_REPEAT); > + if (!vsock) > + return -ENOMEM; > > vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL); > if (!vqs) { > diff --git a/mm/util.c b/mm/util.c > index 7e0c240b5760..9306244b9f41 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -333,7 +333,8 @@ EXPORT_SYMBOL(vm_mmap); > * Uses kmalloc to get the memory but if the allocation fails then falls back > * to the vmalloc allocator. Use kvfree for freeing the memory. > * > - * Reclaim modifiers - __GFP_NORETRY, __GFP_REPEAT and __GFP_NOFAIL are not supported > + * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported. __GFP_REPEAT > + * is supported only for large (>64kB) allocations > */ > void *kvmalloc_node(size_t size, gfp_t flags, int node) > { > @@ -350,8 +351,18 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) > * Make sure that larger requests are not too disruptive - no OOM > * killer and no allocation failure warnings as we have a fallback > */ > - if (size > PAGE_SIZE) > - kmalloc_flags |= __GFP_NORETRY | __GFP_NOWARN; > + if (size > PAGE_SIZE) { > + kmalloc_flags |= __GFP_NOWARN; > + > + /* > + * We have to override __GFP_REPEAT by __GFP_NORETRY for !costly > + * requests because there is no other way to tell the allocator > + * that we want to fail rather than retry endlessly. > + */ > + if (!(kmalloc_flags & __GFP_REPEAT) || > + (size <= PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) > + kmalloc_flags |= __GFP_NORETRY; > + } > > ret = kmalloc_node(size, kmalloc_flags, node); > > -- > 2.11.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f198.google.com (mail-qt0-f198.google.com [209.85.216.198]) by kanga.kvack.org (Postfix) with ESMTP id 739636B0280 for ; Tue, 24 Jan 2017 10:40:42 -0500 (EST) Received: by mail-qt0-f198.google.com with SMTP id l7so156196907qtd.2 for ; Tue, 24 Jan 2017 07:40:42 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id a79si4311323qkj.23.2017.01.24.07.40.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Jan 2017 07:40:41 -0800 (PST) Date: Tue, 24 Jan 2017 17:40:38 +0200 From: "Michael S. Tsirkin" Subject: Re: [PATCH 2/6] mm: support __GFP_REPEAT in kvmalloc_node for >=64kB Message-ID: <20170124173956-mutt-send-email-mst@kernel.org> References: <20170112153717.28943-1-mhocko@kernel.org> <20170112153717.28943-3-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170112153717.28943-3-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , Vlastimil Babka , David Rientjes , Mel Gorman , Johannes Weiner , Al Viro , linux-mm@kvack.org, LKML , Michal Hocko On Thu, Jan 12, 2017 at 04:37:13PM +0100, Michal Hocko wrote: > From: Michal Hocko > > vhost code uses __GFP_REPEAT when allocating vhost_virtqueue resp. > vhost_vsock because it would really like to prefer kmalloc to the > vmalloc fallback - see 23cc5a991c7a ("vhost-net: extend device > allocation to vmalloc") for more context. Michael Tsirkin has also > noted: > " > __GFP_REPEAT overhead is during allocation time. Using vmalloc means all > accesses are slowed down. Allocation is not on data path, accesses are. > " > > The similar applies to other vhost_kvzalloc users. > > Let's teach kvmalloc_node to handle __GFP_REPEAT properly. There are two > things to be careful about. First we should prevent from the OOM killer > and so have to involve __GFP_NORETRY by default and secondly override > __GFP_REPEAT for !costly order requests as the __GFP_REPEAT is ignored > for !costly orders. > > Supporting __GFP_REPEAT like semantic for !costly request is possible > it would require changes in the page allocator. This is out of scope of > this patch. > > This patch shouldn't introduce any functional change. > > Cc: "Michael S. Tsirkin" > Acked-by: Vlastimil Babka > Signed-off-by: Michal Hocko Assuming the new APIs are upstream I see no reason not to use them in vhost. For vhost bits: Acked-by: Michael S. Tsirkin > --- > drivers/vhost/net.c | 9 +++------ > drivers/vhost/vhost.c | 15 +++------------ > drivers/vhost/vsock.c | 9 +++------ > mm/util.c | 17 ++++++++++++++--- > 4 files changed, 23 insertions(+), 27 deletions(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index 5dc34653274a..105cd04c7414 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -797,12 +797,9 @@ static int vhost_net_open(struct inode *inode, struct file *f) > struct vhost_virtqueue **vqs; > int i; > > - n = kmalloc(sizeof *n, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); > - if (!n) { > - n = vmalloc(sizeof *n); > - if (!n) > - return -ENOMEM; > - } > + n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_REPEAT); > + if (!n) > + return -ENOMEM; > vqs = kmalloc(VHOST_NET_VQ_MAX * sizeof(*vqs), GFP_KERNEL); > if (!vqs) { > kvfree(n); > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index d6432603880c..d2bf8a41f55e 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -515,18 +515,9 @@ long vhost_dev_set_owner(struct vhost_dev *dev) > } > EXPORT_SYMBOL_GPL(vhost_dev_set_owner); > > -static void *vhost_kvzalloc(unsigned long size) > -{ > - void *n = kzalloc(size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); > - > - if (!n) > - n = vzalloc(size); > - return n; > -} > - > struct vhost_umem *vhost_dev_reset_owner_prepare(void) > { > - return vhost_kvzalloc(sizeof(struct vhost_umem)); > + return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL); > } > EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare); > > @@ -1190,7 +1181,7 @@ EXPORT_SYMBOL_GPL(vhost_vq_access_ok); > > static struct vhost_umem *vhost_umem_alloc(void) > { > - struct vhost_umem *umem = vhost_kvzalloc(sizeof(*umem)); > + struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL); > > if (!umem) > return NULL; > @@ -1216,7 +1207,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) > return -EOPNOTSUPP; > if (mem.nregions > max_mem_regions) > return -E2BIG; > - newmem = vhost_kvzalloc(size + mem.nregions * sizeof(*m->regions)); > + newmem = kvzalloc(size + mem.nregions * sizeof(*m->regions), GFP_KERNEL); > if (!newmem) > return -ENOMEM; > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > index bbbf588540ed..7e0159867553 100644 > --- a/drivers/vhost/vsock.c > +++ b/drivers/vhost/vsock.c > @@ -455,12 +455,9 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file) > /* This struct is large and allocation could fail, fall back to vmalloc > * if there is no other way. > */ > - vsock = kzalloc(sizeof(*vsock), GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); > - if (!vsock) { > - vsock = vmalloc(sizeof(*vsock)); > - if (!vsock) > - return -ENOMEM; > - } > + vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_REPEAT); > + if (!vsock) > + return -ENOMEM; > > vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL); > if (!vqs) { > diff --git a/mm/util.c b/mm/util.c > index 7e0c240b5760..9306244b9f41 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -333,7 +333,8 @@ EXPORT_SYMBOL(vm_mmap); > * Uses kmalloc to get the memory but if the allocation fails then falls back > * to the vmalloc allocator. Use kvfree for freeing the memory. > * > - * Reclaim modifiers - __GFP_NORETRY, __GFP_REPEAT and __GFP_NOFAIL are not supported > + * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported. __GFP_REPEAT > + * is supported only for large (>64kB) allocations > */ > void *kvmalloc_node(size_t size, gfp_t flags, int node) > { > @@ -350,8 +351,18 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) > * Make sure that larger requests are not too disruptive - no OOM > * killer and no allocation failure warnings as we have a fallback > */ > - if (size > PAGE_SIZE) > - kmalloc_flags |= __GFP_NORETRY | __GFP_NOWARN; > + if (size > PAGE_SIZE) { > + kmalloc_flags |= __GFP_NOWARN; > + > + /* > + * We have to override __GFP_REPEAT by __GFP_NORETRY for !costly > + * requests because there is no other way to tell the allocator > + * that we want to fail rather than retry endlessly. > + */ > + if (!(kmalloc_flags & __GFP_REPEAT) || > + (size <= PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) > + kmalloc_flags |= __GFP_NORETRY; > + } > > ret = kmalloc_node(size, kmalloc_flags, node); > > -- > 2.11.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org