linux/drivers/iommu/iova.c

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/*
* Copyright © 2006-2009, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*
* Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
*/
#include <linux/iova.h>
#include <linux/module.h>
#include <linux/slab.h>
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
#include <linux/smp.h>
#include <linux/bitops.h>
static bool iova_rcache_insert(struct iova_domain *iovad,
unsigned long pfn,
unsigned long size);
static unsigned long iova_rcache_get(struct iova_domain *iovad,
unsigned long size,
unsigned long limit_pfn);
static void init_iova_rcaches(struct iova_domain *iovad);
static void free_iova_rcaches(struct iova_domain *iovad);
void
init_iova_domain(struct iova_domain *iovad, unsigned long granule,
unsigned long start_pfn, unsigned long pfn_32bit)
{
/*
* IOVA granularity will normally be equal to the smallest
* supported IOMMU page size; both *must* be capable of
* representing individual CPU pages exactly.
*/
BUG_ON((granule > PAGE_SIZE) || !is_power_of_2(granule));
spin_lock_init(&iovad->iova_rbtree_lock);
iovad->rbroot = RB_ROOT;
iovad->cached32_node = NULL;
iovad->granule = granule;
iovad->start_pfn = start_pfn;
iovad->dma_32bit_pfn = pfn_32bit;
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
init_iova_rcaches(iovad);
}
EXPORT_SYMBOL_GPL(init_iova_domain);
static struct rb_node *
__get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
{
if ((*limit_pfn > iovad->dma_32bit_pfn) ||
(iovad->cached32_node == NULL))
return rb_last(&iovad->rbroot);
else {
struct rb_node *prev_node = rb_prev(iovad->cached32_node);
struct iova *curr_iova =
rb_entry(iovad->cached32_node, struct iova, node);
*limit_pfn = curr_iova->pfn_lo - 1;
return prev_node;
}
}
static void
__cached_rbnode_insert_update(struct iova_domain *iovad,
unsigned long limit_pfn, struct iova *new)
{
if (limit_pfn != iovad->dma_32bit_pfn)
return;
iovad->cached32_node = &new->node;
}
static void
__cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
{
struct iova *cached_iova;
struct rb_node *curr;
if (!iovad->cached32_node)
return;
curr = iovad->cached32_node;
cached_iova = rb_entry(curr, struct iova, node);
if (free->pfn_lo >= cached_iova->pfn_lo) {
struct rb_node *node = rb_next(&free->node);
struct iova *iova = rb_entry(node, struct iova, node);
/* only cache if it's below 32bit pfn */
if (node && iova->pfn_lo < iovad->dma_32bit_pfn)
iovad->cached32_node = node;
else
iovad->cached32_node = NULL;
}
}
/* Insert the iova into domain rbtree by holding writer lock */
static void
iova_insert_rbtree(struct rb_root *root, struct iova *iova,
struct rb_node *start)
{
struct rb_node **new, *parent = NULL;
new = (start) ? &start : &(root->rb_node);
/* Figure out where to put new node */
while (*new) {
struct iova *this = rb_entry(*new, struct iova, node);
parent = *new;
if (iova->pfn_lo < this->pfn_lo)
new = &((*new)->rb_left);
else if (iova->pfn_lo > this->pfn_lo)
new = &((*new)->rb_right);
else {
WARN_ON(1); /* this should not happen */
return;
}
}
/* Add new node and rebalance tree. */
rb_link_node(&iova->node, parent, new);
rb_insert_color(&iova->node, root);
}
/*
* Computes the padding size required, to make the start address
* naturally aligned on the power-of-two order of its size
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
*/
static unsigned int
iova_get_pad_size(unsigned int size, unsigned int limit_pfn)
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
{
return (limit_pfn + 1 - size) & (__roundup_pow_of_two(size) - 1);
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
}
static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
unsigned long size, unsigned long limit_pfn,
struct iova *new, bool size_aligned)
{
struct rb_node *prev, *curr = NULL;
unsigned long flags;
unsigned long saved_pfn;
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
unsigned int pad_size = 0;
/* Walk the tree backwards */
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
saved_pfn = limit_pfn;
curr = __get_cached_rbnode(iovad, &limit_pfn);
prev = curr;
while (curr) {
struct iova *curr_iova = rb_entry(curr, struct iova, node);
if (limit_pfn < curr_iova->pfn_lo)
goto move_left;
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
else if (limit_pfn < curr_iova->pfn_hi)
goto adjust_limit_pfn;
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
else {
if (size_aligned)
pad_size = iova_get_pad_size(size, limit_pfn);
if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn)
break; /* found a free slot */
}
adjust_limit_pfn:
iommu/iova: Fix underflow bug in __alloc_and_insert_iova_range Normally, calling alloc_iova() using an iova_domain with insufficient pfns remaining between start_pfn and dma_limit will fail and return a NULL pointer. Unexpectedly, if such a "full" iova_domain contains an iova with pfn_lo == 0, the alloc_iova() call will instead succeed and return an iova containing invalid pfns. This is caused by an underflow bug in __alloc_and_insert_iova_range() that occurs after walking the "full" iova tree when the search ends at the iova with pfn_lo == 0 and limit_pfn is then adjusted to be just below that (-1). This (now huge) limit_pfn gives the impression that a vast amount of space is available between it and start_pfn and thus a new iova is allocated with the invalid pfn_hi value, 0xFFF.... . To rememdy this, a check is introduced to ensure that adjustments to limit_pfn will not underflow. This issue has been observed in the wild, and is easily reproduced with the following sample code. struct iova_domain *iovad = kzalloc(sizeof(*iovad), GFP_KERNEL); struct iova *rsvd_iova, *good_iova, *bad_iova; unsigned long limit_pfn = 3; unsigned long start_pfn = 1; unsigned long va_size = 2; init_iova_domain(iovad, SZ_4K, start_pfn, limit_pfn); rsvd_iova = reserve_iova(iovad, 0, 0); good_iova = alloc_iova(iovad, va_size, limit_pfn, true); bad_iova = alloc_iova(iovad, va_size, limit_pfn, true); Prior to the patch, this yielded: *rsvd_iova == {0, 0} /* Expected */ *good_iova == {2, 3} /* Expected */ *bad_iova == {-2, -1} /* Oh no... */ After the patch, bad_iova is NULL as expected since inadequate space remains between limit_pfn and start_pfn after allocating good_iova. Signed-off-by: Nate Watterson <nwatters@codeaurora.org> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2017-04-07 05:36:20 +00:00
limit_pfn = curr_iova->pfn_lo ? (curr_iova->pfn_lo - 1) : 0;
move_left:
prev = curr;
curr = rb_prev(curr);
}
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
if (!curr) {
if (size_aligned)
pad_size = iova_get_pad_size(size, limit_pfn);
if ((iovad->start_pfn + size + pad_size) > limit_pfn) {
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return -ENOMEM;
}
}
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
/* pfn_lo will point to size aligned address if size_aligned is set */
new->pfn_lo = limit_pfn - (size + pad_size) + 1;
new->pfn_hi = new->pfn_lo + size - 1;
/* If we have 'prev', it's a valid place to start the insertion. */
iova_insert_rbtree(&iovad->rbroot, new, prev);
__cached_rbnode_insert_update(iovad, saved_pfn, new);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return 0;
}
static struct kmem_cache *iova_cache;
static unsigned int iova_cache_users;
static DEFINE_MUTEX(iova_cache_mutex);
struct iova *alloc_iova_mem(void)
{
return kmem_cache_alloc(iova_cache, GFP_ATOMIC);
}
EXPORT_SYMBOL(alloc_iova_mem);
void free_iova_mem(struct iova *iova)
{
kmem_cache_free(iova_cache, iova);
}
EXPORT_SYMBOL(free_iova_mem);
int iova_cache_get(void)
{
mutex_lock(&iova_cache_mutex);
if (!iova_cache_users) {
iova_cache = kmem_cache_create(
"iommu_iova", sizeof(struct iova), 0,
SLAB_HWCACHE_ALIGN, NULL);
if (!iova_cache) {
mutex_unlock(&iova_cache_mutex);
printk(KERN_ERR "Couldn't create iova cache\n");
return -ENOMEM;
}
}
iova_cache_users++;
mutex_unlock(&iova_cache_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(iova_cache_get);
void iova_cache_put(void)
{
mutex_lock(&iova_cache_mutex);
if (WARN_ON(!iova_cache_users)) {
mutex_unlock(&iova_cache_mutex);
return;
}
iova_cache_users--;
if (!iova_cache_users)
kmem_cache_destroy(iova_cache);
mutex_unlock(&iova_cache_mutex);
}
EXPORT_SYMBOL_GPL(iova_cache_put);
/**
* alloc_iova - allocates an iova
* @iovad: - iova domain in question
* @size: - size of page frames to allocate
* @limit_pfn: - max limit address
* @size_aligned: - set if size_aligned address range is required
* This function allocates an iova in the range iovad->start_pfn to limit_pfn,
* searching top-down from limit_pfn to iovad->start_pfn. If the size_aligned
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
* flag is set then the allocated address iova->pfn_lo will be naturally
* aligned on roundup_power_of_two(size).
*/
struct iova *
alloc_iova(struct iova_domain *iovad, unsigned long size,
intel-iommu: optimize sg map/unmap calls This patch adds PageSelectiveInvalidation support replacing existing DomainSelectiveInvalidation for intel_{map/unmap}_sg() calls and also enables to mapping one big contiguous DMA virtual address which is mapped to discontiguous physical address for SG map/unmap calls. "Doamin selective invalidations" wipes out the IOMMU address translation cache based on domain ID where as "Page selective invalidations" wipes out the IOMMU address translation cache for that address mask range which is more cache friendly when compared to Domain selective invalidations. Here is how it is done. 1) changes to iova.c alloc_iova() now takes a bool size_aligned argument, which when when set, returns the io virtual address that is naturally aligned to 2 ^ x, where x is the order of the size requested. Returning this io vitual address which is naturally aligned helps iommu to do the "page selective invalidations" which is IOMMU cache friendly over "domain selective invalidations". 2) Changes to driver/pci/intel-iommu.c Clean up intel_{map/unmap}_{single/sg} () calls so that s/g map/unamp calls is no more dependent on intel_{map/unmap}_single() intel_map_sg() now computes the total DMA virtual address required and allocates the size aligned total DMA virtual address and maps the discontiguous physical address to the allocated contiguous DMA virtual address. In the intel_unmap_sg() case since the DMA virtual address is contiguous and size_aligned, PageSelectiveInvalidation is used replacing earlier DomainSelectiveInvalidations. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Greg KH <greg@kroah.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Suresh B <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21 23:41:58 +00:00
unsigned long limit_pfn,
bool size_aligned)
{
struct iova *new_iova;
int ret;
new_iova = alloc_iova_mem();
if (!new_iova)
return NULL;
ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn,
new_iova, size_aligned);
if (ret) {
free_iova_mem(new_iova);
return NULL;
}
return new_iova;
}
EXPORT_SYMBOL_GPL(alloc_iova);
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
static struct iova *
private_find_iova(struct iova_domain *iovad, unsigned long pfn)
{
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
struct rb_node *node = iovad->rbroot.rb_node;
assert_spin_locked(&iovad->iova_rbtree_lock);
while (node) {
struct iova *iova = rb_entry(node, struct iova, node);
/* If pfn falls within iova's range, return iova */
if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
return iova;
}
if (pfn < iova->pfn_lo)
node = node->rb_left;
else if (pfn > iova->pfn_lo)
node = node->rb_right;
}
return NULL;
}
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
static void private_free_iova(struct iova_domain *iovad, struct iova *iova)
{
assert_spin_locked(&iovad->iova_rbtree_lock);
__cached_rbnode_delete_update(iovad, iova);
rb_erase(&iova->node, &iovad->rbroot);
free_iova_mem(iova);
}
/**
* find_iova - finds an iova for a given pfn
* @iovad: - iova domain in question.
* @pfn: - page frame number
* This function finds and returns an iova belonging to the
* given doamin which matches the given pfn.
*/
struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
{
unsigned long flags;
struct iova *iova;
/* Take the lock so that no other thread is manipulating the rbtree */
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
iova = private_find_iova(iovad, pfn);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return iova;
}
EXPORT_SYMBOL_GPL(find_iova);
/**
* __free_iova - frees the given iova
* @iovad: iova domain in question.
* @iova: iova in question.
* Frees the given iova belonging to the giving domain
*/
void
__free_iova(struct iova_domain *iovad, struct iova *iova)
{
unsigned long flags;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
private_free_iova(iovad, iova);
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
}
EXPORT_SYMBOL_GPL(__free_iova);
/**
* free_iova - finds and frees the iova for a given pfn
* @iovad: - iova domain in question.
* @pfn: - pfn that is allocated previously
* This functions finds an iova for a given pfn and then
* frees the iova from that domain.
*/
void
free_iova(struct iova_domain *iovad, unsigned long pfn)
{
struct iova *iova = find_iova(iovad, pfn);
if (iova)
__free_iova(iovad, iova);
}
EXPORT_SYMBOL_GPL(free_iova);
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
/**
* alloc_iova_fast - allocates an iova from rcache
* @iovad: - iova domain in question
* @size: - size of page frames to allocate
* @limit_pfn: - max limit address
* This function tries to satisfy an iova allocation from the rcache,
* and falls back to regular allocation on failure.
*/
unsigned long
alloc_iova_fast(struct iova_domain *iovad, unsigned long size,
unsigned long limit_pfn)
{
bool flushed_rcache = false;
unsigned long iova_pfn;
struct iova *new_iova;
iova_pfn = iova_rcache_get(iovad, size, limit_pfn);
if (iova_pfn)
return iova_pfn;
retry:
new_iova = alloc_iova(iovad, size, limit_pfn, true);
if (!new_iova) {
unsigned int cpu;
if (flushed_rcache)
return 0;
/* Try replenishing IOVAs by flushing rcache. */
flushed_rcache = true;
iommu/iova: Disable preemption around use of this_cpu_ptr() Between acquiring the this_cpu_ptr() and using it, ideally we don't want to be preempted and work on another CPU's private data. this_cpu_ptr() checks whether or not preemption is disable, and get_cpu_ptr() provides a convenient wrapper for operating on the cpu ptr inside a preemption disabled critical section (which currently is provided by the spinlock). [ 167.997877] BUG: using smp_processor_id() in preemptible [00000000] code: usb-storage/216 [ 167.997940] caller is debug_smp_processor_id+0x17/0x20 [ 167.997945] CPU: 7 PID: 216 Comm: usb-storage Tainted: G U 4.7.0-rc1-gfxbench-RO_Patchwork_1057+ #1 [ 167.997948] Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012 [ 167.997951] 0000000000000000 ffff880118b7f9c8 ffffffff8140dca5 0000000000000007 [ 167.997958] ffffffff81a3a7e9 ffff880118b7f9f8 ffffffff8142a927 0000000000000000 [ 167.997965] ffff8800d499ed58 0000000000000001 00000000000fffff ffff880118b7fa08 [ 167.997971] Call Trace: [ 167.997977] [<ffffffff8140dca5>] dump_stack+0x67/0x92 [ 167.997981] [<ffffffff8142a927>] check_preemption_disabled+0xd7/0xe0 [ 167.997985] [<ffffffff8142a947>] debug_smp_processor_id+0x17/0x20 [ 167.997990] [<ffffffff81507e17>] alloc_iova_fast+0xb7/0x210 [ 167.997994] [<ffffffff8150c55f>] intel_alloc_iova+0x7f/0xd0 [ 167.997998] [<ffffffff8151021d>] intel_map_sg+0xbd/0x240 [ 167.998002] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998009] [<ffffffff81596059>] usb_hcd_map_urb_for_dma+0x4b9/0x5a0 [ 167.998013] [<ffffffff81596d19>] usb_hcd_submit_urb+0xe9/0xaa0 [ 167.998017] [<ffffffff810cff2f>] ? mark_held_locks+0x6f/0xa0 [ 167.998022] [<ffffffff810d525c>] ? __raw_spin_lock_init+0x1c/0x50 [ 167.998025] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998028] [<ffffffff815988f3>] usb_submit_urb+0x3f3/0x5a0 [ 167.998032] [<ffffffff810d0082>] ? trace_hardirqs_on_caller+0x122/0x1b0 [ 167.998035] [<ffffffff81599ae7>] usb_sg_wait+0x67/0x150 [ 167.998039] [<ffffffff815dc202>] usb_stor_bulk_transfer_sglist.part.3+0x82/0xd0 [ 167.998042] [<ffffffff815dc29c>] usb_stor_bulk_srb+0x4c/0x60 [ 167.998045] [<ffffffff815dc42e>] usb_stor_Bulk_transport+0x17e/0x420 [ 167.998049] [<ffffffff815dcf32>] usb_stor_invoke_transport+0x242/0x540 [ 167.998052] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998058] [<ffffffff815dba19>] usb_stor_transparent_scsi_command+0x9/0x10 [ 167.998061] [<ffffffff815de518>] usb_stor_control_thread+0x158/0x260 [ 167.998064] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998067] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998071] [<ffffffff8109ddfa>] kthread+0xea/0x100 [ 167.998078] [<ffffffff817ac6af>] ret_from_fork+0x1f/0x40 [ 167.998081] [<ffffffff8109dd10>] ? kthread_create_on_node+0x1f0/0x1f0 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96293 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Fixes: 9257b4a206fc ('iommu/iova: introduce per-cpu caching to iova allocation') Signed-off-by: Joerg Roedel <jroedel@suse.de>
2016-06-01 11:10:08 +00:00
preempt_disable();
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
for_each_online_cpu(cpu)
free_cpu_cached_iovas(cpu, iovad);
iommu/iova: Disable preemption around use of this_cpu_ptr() Between acquiring the this_cpu_ptr() and using it, ideally we don't want to be preempted and work on another CPU's private data. this_cpu_ptr() checks whether or not preemption is disable, and get_cpu_ptr() provides a convenient wrapper for operating on the cpu ptr inside a preemption disabled critical section (which currently is provided by the spinlock). [ 167.997877] BUG: using smp_processor_id() in preemptible [00000000] code: usb-storage/216 [ 167.997940] caller is debug_smp_processor_id+0x17/0x20 [ 167.997945] CPU: 7 PID: 216 Comm: usb-storage Tainted: G U 4.7.0-rc1-gfxbench-RO_Patchwork_1057+ #1 [ 167.997948] Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012 [ 167.997951] 0000000000000000 ffff880118b7f9c8 ffffffff8140dca5 0000000000000007 [ 167.997958] ffffffff81a3a7e9 ffff880118b7f9f8 ffffffff8142a927 0000000000000000 [ 167.997965] ffff8800d499ed58 0000000000000001 00000000000fffff ffff880118b7fa08 [ 167.997971] Call Trace: [ 167.997977] [<ffffffff8140dca5>] dump_stack+0x67/0x92 [ 167.997981] [<ffffffff8142a927>] check_preemption_disabled+0xd7/0xe0 [ 167.997985] [<ffffffff8142a947>] debug_smp_processor_id+0x17/0x20 [ 167.997990] [<ffffffff81507e17>] alloc_iova_fast+0xb7/0x210 [ 167.997994] [<ffffffff8150c55f>] intel_alloc_iova+0x7f/0xd0 [ 167.997998] [<ffffffff8151021d>] intel_map_sg+0xbd/0x240 [ 167.998002] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998009] [<ffffffff81596059>] usb_hcd_map_urb_for_dma+0x4b9/0x5a0 [ 167.998013] [<ffffffff81596d19>] usb_hcd_submit_urb+0xe9/0xaa0 [ 167.998017] [<ffffffff810cff2f>] ? mark_held_locks+0x6f/0xa0 [ 167.998022] [<ffffffff810d525c>] ? __raw_spin_lock_init+0x1c/0x50 [ 167.998025] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998028] [<ffffffff815988f3>] usb_submit_urb+0x3f3/0x5a0 [ 167.998032] [<ffffffff810d0082>] ? trace_hardirqs_on_caller+0x122/0x1b0 [ 167.998035] [<ffffffff81599ae7>] usb_sg_wait+0x67/0x150 [ 167.998039] [<ffffffff815dc202>] usb_stor_bulk_transfer_sglist.part.3+0x82/0xd0 [ 167.998042] [<ffffffff815dc29c>] usb_stor_bulk_srb+0x4c/0x60 [ 167.998045] [<ffffffff815dc42e>] usb_stor_Bulk_transport+0x17e/0x420 [ 167.998049] [<ffffffff815dcf32>] usb_stor_invoke_transport+0x242/0x540 [ 167.998052] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998058] [<ffffffff815dba19>] usb_stor_transparent_scsi_command+0x9/0x10 [ 167.998061] [<ffffffff815de518>] usb_stor_control_thread+0x158/0x260 [ 167.998064] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998067] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998071] [<ffffffff8109ddfa>] kthread+0xea/0x100 [ 167.998078] [<ffffffff817ac6af>] ret_from_fork+0x1f/0x40 [ 167.998081] [<ffffffff8109dd10>] ? kthread_create_on_node+0x1f0/0x1f0 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96293 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Fixes: 9257b4a206fc ('iommu/iova: introduce per-cpu caching to iova allocation') Signed-off-by: Joerg Roedel <jroedel@suse.de>
2016-06-01 11:10:08 +00:00
preempt_enable();
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
goto retry;
}
return new_iova->pfn_lo;
}
EXPORT_SYMBOL_GPL(alloc_iova_fast);
/**
* free_iova_fast - free iova pfn range into rcache
* @iovad: - iova domain in question.
* @pfn: - pfn that is allocated previously
* @size: - # of pages in range
* This functions frees an iova range by trying to put it into the rcache,
* falling back to regular iova deallocation via free_iova() if this fails.
*/
void
free_iova_fast(struct iova_domain *iovad, unsigned long pfn, unsigned long size)
{
if (iova_rcache_insert(iovad, pfn, size))
return;
free_iova(iovad, pfn);
}
EXPORT_SYMBOL_GPL(free_iova_fast);
/**
* put_iova_domain - destroys the iova doamin
* @iovad: - iova domain in question.
* All the iova's in that domain are destroyed.
*/
void put_iova_domain(struct iova_domain *iovad)
{
struct rb_node *node;
unsigned long flags;
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
free_iova_rcaches(iovad);
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
node = rb_first(&iovad->rbroot);
while (node) {
struct iova *iova = rb_entry(node, struct iova, node);
rb_erase(node, &iovad->rbroot);
free_iova_mem(iova);
node = rb_first(&iovad->rbroot);
}
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
}
EXPORT_SYMBOL_GPL(put_iova_domain);
static int
__is_range_overlap(struct rb_node *node,
unsigned long pfn_lo, unsigned long pfn_hi)
{
struct iova *iova = rb_entry(node, struct iova, node);
if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo))
return 1;
return 0;
}
static inline struct iova *
alloc_and_init_iova(unsigned long pfn_lo, unsigned long pfn_hi)
{
struct iova *iova;
iova = alloc_iova_mem();
if (iova) {
iova->pfn_lo = pfn_lo;
iova->pfn_hi = pfn_hi;
}
return iova;
}
static struct iova *
__insert_new_range(struct iova_domain *iovad,
unsigned long pfn_lo, unsigned long pfn_hi)
{
struct iova *iova;
iova = alloc_and_init_iova(pfn_lo, pfn_hi);
if (iova)
iova_insert_rbtree(&iovad->rbroot, iova, NULL);
return iova;
}
static void
__adjust_overlap_range(struct iova *iova,
unsigned long *pfn_lo, unsigned long *pfn_hi)
{
if (*pfn_lo < iova->pfn_lo)
iova->pfn_lo = *pfn_lo;
if (*pfn_hi > iova->pfn_hi)
*pfn_lo = iova->pfn_hi + 1;
}
/**
* reserve_iova - reserves an iova in the given range
* @iovad: - iova domain pointer
* @pfn_lo: - lower page frame address
* @pfn_hi:- higher pfn adderss
* This function allocates reserves the address range from pfn_lo to pfn_hi so
* that this address is not dished out as part of alloc_iova.
*/
struct iova *
reserve_iova(struct iova_domain *iovad,
unsigned long pfn_lo, unsigned long pfn_hi)
{
struct rb_node *node;
unsigned long flags;
struct iova *iova;
unsigned int overlap = 0;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) {
if (__is_range_overlap(node, pfn_lo, pfn_hi)) {
iova = rb_entry(node, struct iova, node);
__adjust_overlap_range(iova, &pfn_lo, &pfn_hi);
if ((pfn_lo >= iova->pfn_lo) &&
(pfn_hi <= iova->pfn_hi))
goto finish;
overlap = 1;
} else if (overlap)
break;
}
/* We are here either because this is the first reserver node
* or need to insert remaining non overlap addr range
*/
iova = __insert_new_range(iovad, pfn_lo, pfn_hi);
finish:
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return iova;
}
EXPORT_SYMBOL_GPL(reserve_iova);
/**
* copy_reserved_iova - copies the reserved between domains
* @from: - source doamin from where to copy
* @to: - destination domin where to copy
* This function copies reserved iova's from one doamin to
* other.
*/
void
copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
{
unsigned long flags;
struct rb_node *node;
spin_lock_irqsave(&from->iova_rbtree_lock, flags);
for (node = rb_first(&from->rbroot); node; node = rb_next(node)) {
struct iova *iova = rb_entry(node, struct iova, node);
struct iova *new_iova;
new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi);
if (!new_iova)
printk(KERN_ERR "Reserve iova range %lx@%lx failed\n",
iova->pfn_lo, iova->pfn_lo);
}
spin_unlock_irqrestore(&from->iova_rbtree_lock, flags);
}
EXPORT_SYMBOL_GPL(copy_reserved_iova);
struct iova *
split_and_remove_iova(struct iova_domain *iovad, struct iova *iova,
unsigned long pfn_lo, unsigned long pfn_hi)
{
unsigned long flags;
struct iova *prev = NULL, *next = NULL;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
if (iova->pfn_lo < pfn_lo) {
prev = alloc_and_init_iova(iova->pfn_lo, pfn_lo - 1);
if (prev == NULL)
goto error;
}
if (iova->pfn_hi > pfn_hi) {
next = alloc_and_init_iova(pfn_hi + 1, iova->pfn_hi);
if (next == NULL)
goto error;
}
__cached_rbnode_delete_update(iovad, iova);
rb_erase(&iova->node, &iovad->rbroot);
if (prev) {
iova_insert_rbtree(&iovad->rbroot, prev, NULL);
iova->pfn_lo = pfn_lo;
}
if (next) {
iova_insert_rbtree(&iovad->rbroot, next, NULL);
iova->pfn_hi = pfn_hi;
}
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
return iova;
error:
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
if (prev)
free_iova_mem(prev);
return NULL;
}
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
/*
* Magazine caches for IOVA ranges. For an introduction to magazines,
* see the USENIX 2001 paper "Magazines and Vmem: Extending the Slab
* Allocator to Many CPUs and Arbitrary Resources" by Bonwick and Adams.
* For simplicity, we use a static magazine size and don't implement the
* dynamic size tuning described in the paper.
*/
#define IOVA_MAG_SIZE 128
struct iova_magazine {
unsigned long size;
unsigned long pfns[IOVA_MAG_SIZE];
};
struct iova_cpu_rcache {
spinlock_t lock;
struct iova_magazine *loaded;
struct iova_magazine *prev;
};
static struct iova_magazine *iova_magazine_alloc(gfp_t flags)
{
return kzalloc(sizeof(struct iova_magazine), flags);
}
static void iova_magazine_free(struct iova_magazine *mag)
{
kfree(mag);
}
static void
iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
{
unsigned long flags;
int i;
if (!mag)
return;
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
for (i = 0 ; i < mag->size; ++i) {
struct iova *iova = private_find_iova(iovad, mag->pfns[i]);
BUG_ON(!iova);
private_free_iova(iovad, iova);
}
spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
mag->size = 0;
}
static bool iova_magazine_full(struct iova_magazine *mag)
{
return (mag && mag->size == IOVA_MAG_SIZE);
}
static bool iova_magazine_empty(struct iova_magazine *mag)
{
return (!mag || mag->size == 0);
}
static unsigned long iova_magazine_pop(struct iova_magazine *mag,
unsigned long limit_pfn)
{
BUG_ON(iova_magazine_empty(mag));
if (mag->pfns[mag->size - 1] >= limit_pfn)
return 0;
return mag->pfns[--mag->size];
}
static void iova_magazine_push(struct iova_magazine *mag, unsigned long pfn)
{
BUG_ON(iova_magazine_full(mag));
mag->pfns[mag->size++] = pfn;
}
static void init_iova_rcaches(struct iova_domain *iovad)
{
struct iova_cpu_rcache *cpu_rcache;
struct iova_rcache *rcache;
unsigned int cpu;
int i;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
spin_lock_init(&rcache->lock);
rcache->depot_size = 0;
rcache->cpu_rcaches = __alloc_percpu(sizeof(*cpu_rcache), cache_line_size());
if (WARN_ON(!rcache->cpu_rcaches))
continue;
for_each_possible_cpu(cpu) {
cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
spin_lock_init(&cpu_rcache->lock);
cpu_rcache->loaded = iova_magazine_alloc(GFP_KERNEL);
cpu_rcache->prev = iova_magazine_alloc(GFP_KERNEL);
}
}
}
/*
* Try inserting IOVA range starting with 'iova_pfn' into 'rcache', and
* return true on success. Can fail if rcache is full and we can't free
* space, and free_iova() (our only caller) will then return the IOVA
* range to the rbtree instead.
*/
static bool __iova_rcache_insert(struct iova_domain *iovad,
struct iova_rcache *rcache,
unsigned long iova_pfn)
{
struct iova_magazine *mag_to_free = NULL;
struct iova_cpu_rcache *cpu_rcache;
bool can_insert = false;
unsigned long flags;
iommu/iova: Disable preemption around use of this_cpu_ptr() Between acquiring the this_cpu_ptr() and using it, ideally we don't want to be preempted and work on another CPU's private data. this_cpu_ptr() checks whether or not preemption is disable, and get_cpu_ptr() provides a convenient wrapper for operating on the cpu ptr inside a preemption disabled critical section (which currently is provided by the spinlock). [ 167.997877] BUG: using smp_processor_id() in preemptible [00000000] code: usb-storage/216 [ 167.997940] caller is debug_smp_processor_id+0x17/0x20 [ 167.997945] CPU: 7 PID: 216 Comm: usb-storage Tainted: G U 4.7.0-rc1-gfxbench-RO_Patchwork_1057+ #1 [ 167.997948] Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012 [ 167.997951] 0000000000000000 ffff880118b7f9c8 ffffffff8140dca5 0000000000000007 [ 167.997958] ffffffff81a3a7e9 ffff880118b7f9f8 ffffffff8142a927 0000000000000000 [ 167.997965] ffff8800d499ed58 0000000000000001 00000000000fffff ffff880118b7fa08 [ 167.997971] Call Trace: [ 167.997977] [<ffffffff8140dca5>] dump_stack+0x67/0x92 [ 167.997981] [<ffffffff8142a927>] check_preemption_disabled+0xd7/0xe0 [ 167.997985] [<ffffffff8142a947>] debug_smp_processor_id+0x17/0x20 [ 167.997990] [<ffffffff81507e17>] alloc_iova_fast+0xb7/0x210 [ 167.997994] [<ffffffff8150c55f>] intel_alloc_iova+0x7f/0xd0 [ 167.997998] [<ffffffff8151021d>] intel_map_sg+0xbd/0x240 [ 167.998002] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998009] [<ffffffff81596059>] usb_hcd_map_urb_for_dma+0x4b9/0x5a0 [ 167.998013] [<ffffffff81596d19>] usb_hcd_submit_urb+0xe9/0xaa0 [ 167.998017] [<ffffffff810cff2f>] ? mark_held_locks+0x6f/0xa0 [ 167.998022] [<ffffffff810d525c>] ? __raw_spin_lock_init+0x1c/0x50 [ 167.998025] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998028] [<ffffffff815988f3>] usb_submit_urb+0x3f3/0x5a0 [ 167.998032] [<ffffffff810d0082>] ? trace_hardirqs_on_caller+0x122/0x1b0 [ 167.998035] [<ffffffff81599ae7>] usb_sg_wait+0x67/0x150 [ 167.998039] [<ffffffff815dc202>] usb_stor_bulk_transfer_sglist.part.3+0x82/0xd0 [ 167.998042] [<ffffffff815dc29c>] usb_stor_bulk_srb+0x4c/0x60 [ 167.998045] [<ffffffff815dc42e>] usb_stor_Bulk_transport+0x17e/0x420 [ 167.998049] [<ffffffff815dcf32>] usb_stor_invoke_transport+0x242/0x540 [ 167.998052] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998058] [<ffffffff815dba19>] usb_stor_transparent_scsi_command+0x9/0x10 [ 167.998061] [<ffffffff815de518>] usb_stor_control_thread+0x158/0x260 [ 167.998064] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998067] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998071] [<ffffffff8109ddfa>] kthread+0xea/0x100 [ 167.998078] [<ffffffff817ac6af>] ret_from_fork+0x1f/0x40 [ 167.998081] [<ffffffff8109dd10>] ? kthread_create_on_node+0x1f0/0x1f0 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96293 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Fixes: 9257b4a206fc ('iommu/iova: introduce per-cpu caching to iova allocation') Signed-off-by: Joerg Roedel <jroedel@suse.de>
2016-06-01 11:10:08 +00:00
cpu_rcache = get_cpu_ptr(rcache->cpu_rcaches);
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
spin_lock_irqsave(&cpu_rcache->lock, flags);
if (!iova_magazine_full(cpu_rcache->loaded)) {
can_insert = true;
} else if (!iova_magazine_full(cpu_rcache->prev)) {
swap(cpu_rcache->prev, cpu_rcache->loaded);
can_insert = true;
} else {
struct iova_magazine *new_mag = iova_magazine_alloc(GFP_ATOMIC);
if (new_mag) {
spin_lock(&rcache->lock);
if (rcache->depot_size < MAX_GLOBAL_MAGS) {
rcache->depot[rcache->depot_size++] =
cpu_rcache->loaded;
} else {
mag_to_free = cpu_rcache->loaded;
}
spin_unlock(&rcache->lock);
cpu_rcache->loaded = new_mag;
can_insert = true;
}
}
if (can_insert)
iova_magazine_push(cpu_rcache->loaded, iova_pfn);
spin_unlock_irqrestore(&cpu_rcache->lock, flags);
iommu/iova: Disable preemption around use of this_cpu_ptr() Between acquiring the this_cpu_ptr() and using it, ideally we don't want to be preempted and work on another CPU's private data. this_cpu_ptr() checks whether or not preemption is disable, and get_cpu_ptr() provides a convenient wrapper for operating on the cpu ptr inside a preemption disabled critical section (which currently is provided by the spinlock). [ 167.997877] BUG: using smp_processor_id() in preemptible [00000000] code: usb-storage/216 [ 167.997940] caller is debug_smp_processor_id+0x17/0x20 [ 167.997945] CPU: 7 PID: 216 Comm: usb-storage Tainted: G U 4.7.0-rc1-gfxbench-RO_Patchwork_1057+ #1 [ 167.997948] Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012 [ 167.997951] 0000000000000000 ffff880118b7f9c8 ffffffff8140dca5 0000000000000007 [ 167.997958] ffffffff81a3a7e9 ffff880118b7f9f8 ffffffff8142a927 0000000000000000 [ 167.997965] ffff8800d499ed58 0000000000000001 00000000000fffff ffff880118b7fa08 [ 167.997971] Call Trace: [ 167.997977] [<ffffffff8140dca5>] dump_stack+0x67/0x92 [ 167.997981] [<ffffffff8142a927>] check_preemption_disabled+0xd7/0xe0 [ 167.997985] [<ffffffff8142a947>] debug_smp_processor_id+0x17/0x20 [ 167.997990] [<ffffffff81507e17>] alloc_iova_fast+0xb7/0x210 [ 167.997994] [<ffffffff8150c55f>] intel_alloc_iova+0x7f/0xd0 [ 167.997998] [<ffffffff8151021d>] intel_map_sg+0xbd/0x240 [ 167.998002] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998009] [<ffffffff81596059>] usb_hcd_map_urb_for_dma+0x4b9/0x5a0 [ 167.998013] [<ffffffff81596d19>] usb_hcd_submit_urb+0xe9/0xaa0 [ 167.998017] [<ffffffff810cff2f>] ? mark_held_locks+0x6f/0xa0 [ 167.998022] [<ffffffff810d525c>] ? __raw_spin_lock_init+0x1c/0x50 [ 167.998025] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998028] [<ffffffff815988f3>] usb_submit_urb+0x3f3/0x5a0 [ 167.998032] [<ffffffff810d0082>] ? trace_hardirqs_on_caller+0x122/0x1b0 [ 167.998035] [<ffffffff81599ae7>] usb_sg_wait+0x67/0x150 [ 167.998039] [<ffffffff815dc202>] usb_stor_bulk_transfer_sglist.part.3+0x82/0xd0 [ 167.998042] [<ffffffff815dc29c>] usb_stor_bulk_srb+0x4c/0x60 [ 167.998045] [<ffffffff815dc42e>] usb_stor_Bulk_transport+0x17e/0x420 [ 167.998049] [<ffffffff815dcf32>] usb_stor_invoke_transport+0x242/0x540 [ 167.998052] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998058] [<ffffffff815dba19>] usb_stor_transparent_scsi_command+0x9/0x10 [ 167.998061] [<ffffffff815de518>] usb_stor_control_thread+0x158/0x260 [ 167.998064] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998067] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998071] [<ffffffff8109ddfa>] kthread+0xea/0x100 [ 167.998078] [<ffffffff817ac6af>] ret_from_fork+0x1f/0x40 [ 167.998081] [<ffffffff8109dd10>] ? kthread_create_on_node+0x1f0/0x1f0 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96293 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Fixes: 9257b4a206fc ('iommu/iova: introduce per-cpu caching to iova allocation') Signed-off-by: Joerg Roedel <jroedel@suse.de>
2016-06-01 11:10:08 +00:00
put_cpu_ptr(rcache->cpu_rcaches);
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
if (mag_to_free) {
iova_magazine_free_pfns(mag_to_free, iovad);
iova_magazine_free(mag_to_free);
}
return can_insert;
}
static bool iova_rcache_insert(struct iova_domain *iovad, unsigned long pfn,
unsigned long size)
{
unsigned int log_size = order_base_2(size);
if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
return false;
return __iova_rcache_insert(iovad, &iovad->rcaches[log_size], pfn);
}
/*
* Caller wants to allocate a new IOVA range from 'rcache'. If we can
* satisfy the request, return a matching non-NULL range and remove
* it from the 'rcache'.
*/
static unsigned long __iova_rcache_get(struct iova_rcache *rcache,
unsigned long limit_pfn)
{
struct iova_cpu_rcache *cpu_rcache;
unsigned long iova_pfn = 0;
bool has_pfn = false;
unsigned long flags;
iommu/iova: Disable preemption around use of this_cpu_ptr() Between acquiring the this_cpu_ptr() and using it, ideally we don't want to be preempted and work on another CPU's private data. this_cpu_ptr() checks whether or not preemption is disable, and get_cpu_ptr() provides a convenient wrapper for operating on the cpu ptr inside a preemption disabled critical section (which currently is provided by the spinlock). [ 167.997877] BUG: using smp_processor_id() in preemptible [00000000] code: usb-storage/216 [ 167.997940] caller is debug_smp_processor_id+0x17/0x20 [ 167.997945] CPU: 7 PID: 216 Comm: usb-storage Tainted: G U 4.7.0-rc1-gfxbench-RO_Patchwork_1057+ #1 [ 167.997948] Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012 [ 167.997951] 0000000000000000 ffff880118b7f9c8 ffffffff8140dca5 0000000000000007 [ 167.997958] ffffffff81a3a7e9 ffff880118b7f9f8 ffffffff8142a927 0000000000000000 [ 167.997965] ffff8800d499ed58 0000000000000001 00000000000fffff ffff880118b7fa08 [ 167.997971] Call Trace: [ 167.997977] [<ffffffff8140dca5>] dump_stack+0x67/0x92 [ 167.997981] [<ffffffff8142a927>] check_preemption_disabled+0xd7/0xe0 [ 167.997985] [<ffffffff8142a947>] debug_smp_processor_id+0x17/0x20 [ 167.997990] [<ffffffff81507e17>] alloc_iova_fast+0xb7/0x210 [ 167.997994] [<ffffffff8150c55f>] intel_alloc_iova+0x7f/0xd0 [ 167.997998] [<ffffffff8151021d>] intel_map_sg+0xbd/0x240 [ 167.998002] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998009] [<ffffffff81596059>] usb_hcd_map_urb_for_dma+0x4b9/0x5a0 [ 167.998013] [<ffffffff81596d19>] usb_hcd_submit_urb+0xe9/0xaa0 [ 167.998017] [<ffffffff810cff2f>] ? mark_held_locks+0x6f/0xa0 [ 167.998022] [<ffffffff810d525c>] ? __raw_spin_lock_init+0x1c/0x50 [ 167.998025] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998028] [<ffffffff815988f3>] usb_submit_urb+0x3f3/0x5a0 [ 167.998032] [<ffffffff810d0082>] ? trace_hardirqs_on_caller+0x122/0x1b0 [ 167.998035] [<ffffffff81599ae7>] usb_sg_wait+0x67/0x150 [ 167.998039] [<ffffffff815dc202>] usb_stor_bulk_transfer_sglist.part.3+0x82/0xd0 [ 167.998042] [<ffffffff815dc29c>] usb_stor_bulk_srb+0x4c/0x60 [ 167.998045] [<ffffffff815dc42e>] usb_stor_Bulk_transport+0x17e/0x420 [ 167.998049] [<ffffffff815dcf32>] usb_stor_invoke_transport+0x242/0x540 [ 167.998052] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998058] [<ffffffff815dba19>] usb_stor_transparent_scsi_command+0x9/0x10 [ 167.998061] [<ffffffff815de518>] usb_stor_control_thread+0x158/0x260 [ 167.998064] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998067] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998071] [<ffffffff8109ddfa>] kthread+0xea/0x100 [ 167.998078] [<ffffffff817ac6af>] ret_from_fork+0x1f/0x40 [ 167.998081] [<ffffffff8109dd10>] ? kthread_create_on_node+0x1f0/0x1f0 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96293 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Fixes: 9257b4a206fc ('iommu/iova: introduce per-cpu caching to iova allocation') Signed-off-by: Joerg Roedel <jroedel@suse.de>
2016-06-01 11:10:08 +00:00
cpu_rcache = get_cpu_ptr(rcache->cpu_rcaches);
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
spin_lock_irqsave(&cpu_rcache->lock, flags);
if (!iova_magazine_empty(cpu_rcache->loaded)) {
has_pfn = true;
} else if (!iova_magazine_empty(cpu_rcache->prev)) {
swap(cpu_rcache->prev, cpu_rcache->loaded);
has_pfn = true;
} else {
spin_lock(&rcache->lock);
if (rcache->depot_size > 0) {
iova_magazine_free(cpu_rcache->loaded);
cpu_rcache->loaded = rcache->depot[--rcache->depot_size];
has_pfn = true;
}
spin_unlock(&rcache->lock);
}
if (has_pfn)
iova_pfn = iova_magazine_pop(cpu_rcache->loaded, limit_pfn);
spin_unlock_irqrestore(&cpu_rcache->lock, flags);
iommu/iova: Disable preemption around use of this_cpu_ptr() Between acquiring the this_cpu_ptr() and using it, ideally we don't want to be preempted and work on another CPU's private data. this_cpu_ptr() checks whether or not preemption is disable, and get_cpu_ptr() provides a convenient wrapper for operating on the cpu ptr inside a preemption disabled critical section (which currently is provided by the spinlock). [ 167.997877] BUG: using smp_processor_id() in preemptible [00000000] code: usb-storage/216 [ 167.997940] caller is debug_smp_processor_id+0x17/0x20 [ 167.997945] CPU: 7 PID: 216 Comm: usb-storage Tainted: G U 4.7.0-rc1-gfxbench-RO_Patchwork_1057+ #1 [ 167.997948] Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012 [ 167.997951] 0000000000000000 ffff880118b7f9c8 ffffffff8140dca5 0000000000000007 [ 167.997958] ffffffff81a3a7e9 ffff880118b7f9f8 ffffffff8142a927 0000000000000000 [ 167.997965] ffff8800d499ed58 0000000000000001 00000000000fffff ffff880118b7fa08 [ 167.997971] Call Trace: [ 167.997977] [<ffffffff8140dca5>] dump_stack+0x67/0x92 [ 167.997981] [<ffffffff8142a927>] check_preemption_disabled+0xd7/0xe0 [ 167.997985] [<ffffffff8142a947>] debug_smp_processor_id+0x17/0x20 [ 167.997990] [<ffffffff81507e17>] alloc_iova_fast+0xb7/0x210 [ 167.997994] [<ffffffff8150c55f>] intel_alloc_iova+0x7f/0xd0 [ 167.997998] [<ffffffff8151021d>] intel_map_sg+0xbd/0x240 [ 167.998002] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998009] [<ffffffff81596059>] usb_hcd_map_urb_for_dma+0x4b9/0x5a0 [ 167.998013] [<ffffffff81596d19>] usb_hcd_submit_urb+0xe9/0xaa0 [ 167.998017] [<ffffffff810cff2f>] ? mark_held_locks+0x6f/0xa0 [ 167.998022] [<ffffffff810d525c>] ? __raw_spin_lock_init+0x1c/0x50 [ 167.998025] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998028] [<ffffffff815988f3>] usb_submit_urb+0x3f3/0x5a0 [ 167.998032] [<ffffffff810d0082>] ? trace_hardirqs_on_caller+0x122/0x1b0 [ 167.998035] [<ffffffff81599ae7>] usb_sg_wait+0x67/0x150 [ 167.998039] [<ffffffff815dc202>] usb_stor_bulk_transfer_sglist.part.3+0x82/0xd0 [ 167.998042] [<ffffffff815dc29c>] usb_stor_bulk_srb+0x4c/0x60 [ 167.998045] [<ffffffff815dc42e>] usb_stor_Bulk_transport+0x17e/0x420 [ 167.998049] [<ffffffff815dcf32>] usb_stor_invoke_transport+0x242/0x540 [ 167.998052] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20 [ 167.998058] [<ffffffff815dba19>] usb_stor_transparent_scsi_command+0x9/0x10 [ 167.998061] [<ffffffff815de518>] usb_stor_control_thread+0x158/0x260 [ 167.998064] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998067] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20 [ 167.998071] [<ffffffff8109ddfa>] kthread+0xea/0x100 [ 167.998078] [<ffffffff817ac6af>] ret_from_fork+0x1f/0x40 [ 167.998081] [<ffffffff8109dd10>] ? kthread_create_on_node+0x1f0/0x1f0 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96293 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Fixes: 9257b4a206fc ('iommu/iova: introduce per-cpu caching to iova allocation') Signed-off-by: Joerg Roedel <jroedel@suse.de>
2016-06-01 11:10:08 +00:00
put_cpu_ptr(rcache->cpu_rcaches);
iommu/iova: introduce per-cpu caching to iova allocation IOVA allocation has two problems that impede high-throughput I/O. First, it can do a linear search over the allocated IOVA ranges. Second, the rbtree spinlock that serializes IOVA allocations becomes contended. Address these problems by creating an API for caching allocated IOVA ranges, so that the IOVA allocator isn't accessed frequently. This patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs without taking the rbtree spinlock. The per-CPU caches are backed by a global cache, to avoid invoking the (linear-time) IOVA allocator without needing to make the per-CPU cache size excessive. This design is based on magazines, as described in "Magazines and Vmem: Extending the Slab Allocator to Many CPUs and Arbitrary Resources" (currently available at https://www.usenix.org/legacy/event/usenix01/bonwick.html) Adding caching on top of the existing rbtree allocator maintains the property that IOVAs are densely packed in the IO virtual address space, which is important for keeping IOMMU page table usage low. To keep the cache size reasonable, we bound the IOVA space a CPU can cache by 32 MiB (we cache a bounded number of IOVA ranges, and only ranges of size <= 128 KiB). The shared global cache is bounded at 4 MiB of IOVA space. Signed-off-by: Omer Peleg <omer@cs.technion.ac.il> [mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message] Signed-off-by: Adam Morrison <mad@cs.technion.ac.il> Reviewed-by: Shaohua Li <shli@fb.com> Reviewed-by: Ben Serebrin <serebrin@google.com> [dwmw2: split out VT-d part into a separate patch] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2016-04-20 08:34:11 +00:00
return iova_pfn;
}
/*
* Try to satisfy IOVA allocation range from rcache. Fail if requested
* size is too big or the DMA limit we are given isn't satisfied by the
* top element in the magazine.
*/
static unsigned long iova_rcache_get(struct iova_domain *iovad,
unsigned long size,
unsigned long limit_pfn)
{
unsigned int log_size = order_base_2(size);
if (log_size >= IOVA_RANGE_CACHE_MAX_SIZE)
return 0;
return __iova_rcache_get(&iovad->rcaches[log_size], limit_pfn);
}
/*
* Free a cpu's rcache.
*/
static void free_cpu_iova_rcache(unsigned int cpu, struct iova_domain *iovad,
struct iova_rcache *rcache)
{
struct iova_cpu_rcache *cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
unsigned long flags;
spin_lock_irqsave(&cpu_rcache->lock, flags);
iova_magazine_free_pfns(cpu_rcache->loaded, iovad);
iova_magazine_free(cpu_rcache->loaded);
iova_magazine_free_pfns(cpu_rcache->prev, iovad);
iova_magazine_free(cpu_rcache->prev);
spin_unlock_irqrestore(&cpu_rcache->lock, flags);
}
/*
* free rcache data structures.
*/
static void free_iova_rcaches(struct iova_domain *iovad)
{
struct iova_rcache *rcache;
unsigned long flags;
unsigned int cpu;
int i, j;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
for_each_possible_cpu(cpu)
free_cpu_iova_rcache(cpu, iovad, rcache);
spin_lock_irqsave(&rcache->lock, flags);
free_percpu(rcache->cpu_rcaches);
for (j = 0; j < rcache->depot_size; ++j) {
iova_magazine_free_pfns(rcache->depot[j], iovad);
iova_magazine_free(rcache->depot[j]);
}
spin_unlock_irqrestore(&rcache->lock, flags);
}
}
/*
* free all the IOVA ranges cached by a cpu (used when cpu is unplugged)
*/
void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad)
{
struct iova_cpu_rcache *cpu_rcache;
struct iova_rcache *rcache;
unsigned long flags;
int i;
for (i = 0; i < IOVA_RANGE_CACHE_MAX_SIZE; ++i) {
rcache = &iovad->rcaches[i];
cpu_rcache = per_cpu_ptr(rcache->cpu_rcaches, cpu);
spin_lock_irqsave(&cpu_rcache->lock, flags);
iova_magazine_free_pfns(cpu_rcache->loaded, iovad);
iova_magazine_free_pfns(cpu_rcache->prev, iovad);
spin_unlock_irqrestore(&cpu_rcache->lock, flags);
}
}
MODULE_AUTHOR("Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>");
MODULE_LICENSE("GPL");