| Message ID | 1459777603-23618-3-git-send-email-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On ma, 2016-04-04 at 14:46 +0100, Chris Wilson wrote: > vmaps are temporary kernel mappings that may be of long duration. > Reusing a vmap on an object is preferrable for a driver as the cost of > setting up the vmap can otherwise dominate the operation on the object. > However, the vmap address space is rather limited on 32bit systems and > so we add a notification for vmap pressure in order for the driver to > release any cached vmappings. > > The interface is styled after the oom-notifier where the callees are > passed a pointer to an unsigned long counter for them to indicate if they > have freed any space. > > v2: Guard the blocking notifier call with gfpflags_allow_blocking() > v3: Correct typo in forward declaration and move to head of file > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: David Rientjes <rientjes@google.com> > Cc: Roman Peniaev <r.peniaev@gmail.com> > Cc: Mel Gorman <mgorman@techsingularity.net> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Acked-by: Andrew Morton <akpm@linux-foundation.org> # for inclusion via DRM > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> > --- > include/linux/vmalloc.h | 4 ++++ > mm/vmalloc.c | 27 +++++++++++++++++++++++++++ > 2 files changed, 31 insertions(+) > > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h > index d1f1d338af20..8b51df3ab334 100644 > --- a/include/linux/vmalloc.h > +++ b/include/linux/vmalloc.h > @@ -8,6 +8,7 @@ > #include > > struct vm_area_struct; /* vma defining user mapping in mm_types.h */ > +struct notifier_block; /* in notifier.h */ > > /* bits in flags of vmalloc's vm_struct below */ > #define VM_IOREMAP 0x00000001 /* ioremap() and friends */ > @@ -187,4 +188,7 @@ pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) > #define VMALLOC_TOTAL 0UL > #endif > > +int register_vmap_purge_notifier(struct notifier_block *nb); > +int unregister_vmap_purge_notifier(struct notifier_block *nb); > + > #endif /* _LINUX_VMALLOC_H */ > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index ae7d20b447ff..293889d7f482 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -344,6 +345,8 @@ static void __insert_vmap_area(struct vmap_area *va) > > static void purge_vmap_area_lazy(void); > > +static BLOCKING_NOTIFIER_HEAD(vmap_notify_list); > + > /* > * Allocate a region of KVA of the specified size and alignment, within the > * vstart and vend. > @@ -363,6 +366,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > BUG_ON(offset_in_page(size)); > BUG_ON(!is_power_of_2(align)); > > + might_sleep_if(gfpflags_allow_blocking(gfp_mask)); > + > va = kmalloc_node(sizeof(struct vmap_area), > gfp_mask & GFP_RECLAIM_MASK, node); > if (unlikely(!va)) > @@ -468,6 +473,16 @@ overflow: > purged = 1; > goto retry; > } > + > + if (gfpflags_allow_blocking(gfp_mask)) { > + unsigned long freed = 0; > + blocking_notifier_call_chain(&vmap_notify_list, 0, &freed); > + if (freed > 0) { > + purged = 0; > + goto retry; > + } > + } > + > if (printk_ratelimit()) > pr_warn("vmap allocation for size %lu failed: use vmalloc= to increase size\n", > size); > @@ -475,6 +490,18 @@ overflow: > return ERR_PTR(-EBUSY); > } > > +int register_vmap_purge_notifier(struct notifier_block *nb) > +{ > + return blocking_notifier_chain_register(&vmap_notify_list, nb); > +} > +EXPORT_SYMBOL_GPL(register_vmap_purge_notifier); > + > +int unregister_vmap_purge_notifier(struct notifier_block *nb) > +{ > + return blocking_notifier_chain_unregister(&vmap_notify_list, nb); > +} > +EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier); > + > static void __free_vmap_area(struct vmap_area *va) > { > BUG_ON(RB_EMPTY_NODE(&va->rb_node));
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index d1f1d338af20..8b51df3ab334 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -8,6 +8,7 @@ #include <linux/rbtree.h> struct vm_area_struct; /* vma defining user mapping in mm_types.h */ +struct notifier_block; /* in notifier.h */ /* bits in flags of vmalloc's vm_struct below */ #define VM_IOREMAP 0x00000001 /* ioremap() and friends */ @@ -187,4 +188,7 @@ pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) #define VMALLOC_TOTAL 0UL #endif +int register_vmap_purge_notifier(struct notifier_block *nb); +int unregister_vmap_purge_notifier(struct notifier_block *nb); + #endif /* _LINUX_VMALLOC_H */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index ae7d20b447ff..293889d7f482 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -21,6 +21,7 @@ #include <linux/debugobjects.h> #include <linux/kallsyms.h> #include <linux/list.h> +#include <linux/notifier.h> #include <linux/rbtree.h> #include <linux/radix-tree.h> #include <linux/rcupdate.h> @@ -344,6 +345,8 @@ static void __insert_vmap_area(struct vmap_area *va) static void purge_vmap_area_lazy(void); +static BLOCKING_NOTIFIER_HEAD(vmap_notify_list); + /* * Allocate a region of KVA of the specified size and alignment, within the * vstart and vend. @@ -363,6 +366,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, BUG_ON(offset_in_page(size)); BUG_ON(!is_power_of_2(align)); + might_sleep_if(gfpflags_allow_blocking(gfp_mask)); + va = kmalloc_node(sizeof(struct vmap_area), gfp_mask & GFP_RECLAIM_MASK, node); if (unlikely(!va)) @@ -468,6 +473,16 @@ overflow: purged = 1; goto retry; } + + if (gfpflags_allow_blocking(gfp_mask)) { + unsigned long freed = 0; + blocking_notifier_call_chain(&vmap_notify_list, 0, &freed); + if (freed > 0) { + purged = 0; + goto retry; + } + } + if (printk_ratelimit()) pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n", size); @@ -475,6 +490,18 @@ overflow: return ERR_PTR(-EBUSY); } +int register_vmap_purge_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&vmap_notify_list, nb); +} +EXPORT_SYMBOL_GPL(register_vmap_purge_notifier); + +int unregister_vmap_purge_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&vmap_notify_list, nb); +} +EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier); + static void __free_vmap_area(struct vmap_area *va) { BUG_ON(RB_EMPTY_NODE(&va->rb_node));