From: Alex Williamson <alex.williamson@redhat.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Alexander Graf <agraf@suse.de>,
Gavin Shan <gwshan@linux.vnet.ibm.com>,
Alexander Gordeev <agordeev@redhat.com>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 05/24] vfio: powerpc/spapr: Move locked_vm accounting to helpers
Date: Mon, 02 Feb 2015 17:12:06 -0700 [thread overview]
Message-ID: <1422922326.22865.447.camel@redhat.com> (raw)
In-Reply-To: <1422523325-1389-6-git-send-email-aik@ozlabs.ru>
On Thu, 2015-01-29 at 20:21 +1100, Alexey Kardashevskiy wrote:
> There moves locked pages accounting to helpers.
> Later they will be reused for Dynamic DMA windows (DDW).
>
> While we are here, update the comment explaining why RLIMIT_MEMLOCK
> might be required to be bigger than the guest RAM. This also prints
> pid of the current process in pr_warn/pr_debug.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> drivers/vfio/vfio_iommu_spapr_tce.c | 72 +++++++++++++++++++++++++++----------
> 1 file changed, 53 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index c596053..29d5708 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -29,6 +29,47 @@
> static void tce_iommu_detach_group(void *iommu_data,
> struct iommu_group *iommu_group);
>
> +#define IOMMU_TABLE_PAGES(tbl) \
> + (((tbl)->it_size << (tbl)->it_page_shift) >> PAGE_SHIFT)
A bit of an infringement on the global namespace with such a generic
name.
> +
> +static long try_increment_locked_vm(long npages)
> +{
> + long ret = 0, locked, lock_limit;
> +
> + if (!current || !current->mm)
> + return -ESRCH; /* process exited */
> +
> + down_write(¤t->mm->mmap_sem);
> + locked = current->mm->locked_vm + npages;
> + lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
> + if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
> + pr_warn("[%d] RLIMIT_MEMLOCK (%ld) exceeded\n",
> + current->pid, rlimit(RLIMIT_MEMLOCK));
> + ret = -ENOMEM;
> + } else {
> + current->mm->locked_vm += npages;
> + }
> + pr_debug("[%d] RLIMIT_MEMLOCK+ %ld pages\n", current->pid,
> + current->mm->locked_vm);
> + up_write(¤t->mm->mmap_sem);
> +
> + return ret;
> +}
> +
> +static void decrement_locked_vm(long npages)
> +{
> + if (!current || !current->mm)
> + return; /* process exited */
> +
> + down_write(¤t->mm->mmap_sem);
> + if (npages > current->mm->locked_vm)
> + npages = current->mm->locked_vm;
> + current->mm->locked_vm -= npages;
> + pr_debug("[%d] RLIMIT_MEMLOCK- %ld pages\n", current->pid,
> + current->mm->locked_vm);
> + up_write(¤t->mm->mmap_sem);
> +}
> +
> /*
> * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
> *
> @@ -66,8 +107,6 @@ static bool tce_check_page_size(struct page *page, unsigned page_shift)
> static int tce_iommu_enable(struct tce_container *container)
> {
> int ret = 0;
> - unsigned long locked, lock_limit, npages;
> - struct iommu_table *tbl = container->tbl;
>
> if (!container->tbl)
> return -ENXIO;
> @@ -95,21 +134,19 @@ static int tce_iommu_enable(struct tce_container *container)
> * Also we don't have a nice way to fail on H_PUT_TCE due to ulimits,
> * that would effectively kill the guest at random points, much better
> * enforcing the limit based on the max that the guest can map.
> + *
> + * Unfortunately at the moment it counts whole tables, no matter how
> + * much memory the guest has. I.e. for 4GB guest and 4 IOMMU groups
> + * each with 2GB DMA window, 8GB will be counted here. The reason for
> + * this is that we cannot tell here the amount of RAM used by the guest
> + * as this information is only available from KVM and VFIO is
> + * KVM agnostic.
> */
> - down_write(¤t->mm->mmap_sem);
> - npages = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
> - locked = current->mm->locked_vm + npages;
> - lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
> - if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
> - pr_warn("RLIMIT_MEMLOCK (%ld) exceeded\n",
> - rlimit(RLIMIT_MEMLOCK));
> - ret = -ENOMEM;
> - } else {
> + ret = try_increment_locked_vm(IOMMU_TABLE_PAGES(container->tbl));
> + if (ret)
> + return ret;
>
> - current->mm->locked_vm += npages;
> - container->enabled = true;
> - }
> - up_write(¤t->mm->mmap_sem);
> + container->enabled = true;
>
> return ret;
> }
> @@ -124,10 +161,7 @@ static void tce_iommu_disable(struct tce_container *container)
> if (!container->tbl || !current->mm)
> return;
>
> - down_write(¤t->mm->mmap_sem);
> - current->mm->locked_vm -= (container->tbl->it_size <<
> - container->tbl->it_page_shift) >> PAGE_SHIFT;
> - up_write(¤t->mm->mmap_sem);
> + decrement_locked_vm(IOMMU_TABLE_PAGES(container->tbl));
> }
>
> static void *tce_iommu_open(unsigned long arg)
next prev parent reply other threads:[~2015-02-03 0:12 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-29 9:21 [PATCH v3 00/24] powerpc/iommu/vfio: Enable Dynamic DMA windows Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 01/24] vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU driver Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 02/24] vfio: powerpc/iommu: Check that TCE page size is equal to it_page_size Alexey Kardashevskiy
2015-02-02 21:45 ` Alex Williamson
2015-01-29 9:21 ` [PATCH v3 03/24] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 04/24] vfio: powerpc/spapr: Use it_page_size Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 05/24] vfio: powerpc/spapr: Move locked_vm accounting to helpers Alexey Kardashevskiy
2015-02-03 0:12 ` Alex Williamson [this message]
2015-01-29 9:21 ` [PATCH v3 06/24] powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 07/24] powerpc/iommu: Introduce iommu_table_alloc() helper Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 08/24] powerpc/spapr: vfio: Switch from iommu_table to new powerpc_iommu Alexey Kardashevskiy
2015-02-03 0:12 ` Alex Williamson
2015-02-04 13:32 ` Alexander Graf
2015-02-05 4:58 ` Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 09/24] powerpc/iommu: Fix IOMMU ownership control functions Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 10/24] powerpc/powernv/ioda2: Rework IOMMU ownership control Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 11/24] powerpc/powernv/ioda/ioda2: Rework tce_build()/tce_free() Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 12/24] powerpc/iommu/powernv: Release replaced TCE Alexey Kardashevskiy
2015-02-04 6:08 ` Paul Mackerras
2015-02-05 4:57 ` Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 13/24] powerpc/pseries/lpar: Enable VFIO Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 14/24] vfio: powerpc/spapr: Register memory Alexey Kardashevskiy
2015-02-03 0:11 ` Alex Williamson
2015-02-03 5:51 ` Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 15/24] poweppc/powernv/ioda2: Rework iommu_table creation Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 16/24] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_create_table Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 17/24] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window Alexey Kardashevskiy
2015-01-29 9:21 ` [PATCH v3 18/24] powerpc/iommu: Split iommu_free_table into 2 helpers Alexey Kardashevskiy
2015-01-29 9:22 ` [PATCH v3 19/24] powerpc/powernv: Implement multilevel TCE tables Alexey Kardashevskiy
2015-01-29 9:22 ` [PATCH v3 20/24] powerpc/powernv: Change prototypes to receive iommu Alexey Kardashevskiy
2015-01-29 9:22 ` [PATCH v3 21/24] powerpc/powernv/ioda: Define and implement DMA table/window management callbacks Alexey Kardashevskiy
2015-01-29 9:22 ` [PATCH v3 22/24] powerpc/iommu: Get rid of ownership helpers Alexey Kardashevskiy
2015-01-29 9:22 ` [PATCH v3 23/24] vfio/spapr: Enable multiple groups in a container Alexey Kardashevskiy
2015-01-29 9:22 ` [PATCH v3 24/24] vfio: powerpc/spapr: Support Dynamic DMA windows Alexey Kardashevskiy
2015-02-03 2:53 ` Alex Williamson
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