From f011c2dae6cffc50ef67d9bd937b488ba5db8913 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 19 Nov 2008 15:36:32 -0800 Subject: mm: vmalloc allocator off by one Fix off by one bug in the KVA allocator that can leave gaps in the address space. Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/vmalloc.c') diff --git a/mm/vmalloc.c b/mm/vmalloc.c index ba6b0f5f7fac..46aab4dbf618 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -362,7 +362,7 @@ retry: goto found; } - while (addr + size >= first->va_start && addr + size <= vend) { + while (addr + size > first->va_start && addr + size <= vend) { addr = ALIGN(first->va_end + PAGE_SIZE, align); n = rb_next(&first->rb_node); -- cgit v1.2.3 From 496850e5f5a372029ceb2b35c811770a9bb073b6 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 19 Nov 2008 15:36:33 -0800 Subject: mm: vmalloc failure flush fix An initial vmalloc failure should start off a synchronous flush of lazy areas, in case someone is in progress flushing them already, which could cause us to return an allocation failure even if there is plenty of KVA free. Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmalloc.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'mm/vmalloc.c') diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 46aab4dbf618..04f5e320e744 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -521,6 +521,17 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end, spin_unlock(&purge_lock); } +/* + * Kick off a purge of the outstanding lazy areas. Don't bother if somebody + * is already purging. + */ +static void try_purge_vmap_area_lazy(void) +{ + unsigned long start = ULONG_MAX, end = 0; + + __purge_vmap_area_lazy(&start, &end, 0, 0); +} + /* * Kick off a purge of the outstanding lazy areas. */ @@ -528,7 +539,7 @@ static void purge_vmap_area_lazy(void) { unsigned long start = ULONG_MAX, end = 0; - __purge_vmap_area_lazy(&start, &end, 0, 0); + __purge_vmap_area_lazy(&start, &end, 1, 0); } /* @@ -539,7 +550,7 @@ static void free_unmap_vmap_area(struct vmap_area *va) va->flags |= VM_LAZY_FREE; atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr); if (unlikely(atomic_read(&vmap_lazy_nr) > lazy_max_pages())) - purge_vmap_area_lazy(); + try_purge_vmap_area_lazy(); } static struct vmap_area *find_vmap_area(unsigned long addr) -- cgit v1.2.3 From 0ae15132a4f5c758a6ffcde74495641dc3f62ba1 Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Wed, 19 Nov 2008 15:36:33 -0800 Subject: mm: vmalloc search restart fix Current vmalloc restart search for a free area in case we can't find one. The reason is there are areas which are lazily freed, and could be possibly freed now. However, current implementation start searching the tree from the last failing address, which is pretty much by definition at the end of address space. So, we fail. The proposal of this patch is to restart the search from the beginning of the requested vstart address. This fixes the regression in running KVM virtual machines for me, described in http://lkml.org/lkml/2008/10/28/349, caused by commit db64fe02258f1507e13fe5212a989922323685ce. Signed-off-by: Glauber Costa Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmalloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/vmalloc.c') diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 04f5e320e744..30f826d484f0 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -324,14 +324,14 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, BUG_ON(size & ~PAGE_MASK); - addr = ALIGN(vstart, align); - va = kmalloc_node(sizeof(struct vmap_area), gfp_mask & GFP_RECLAIM_MASK, node); if (unlikely(!va)) return ERR_PTR(-ENOMEM); retry: + addr = ALIGN(vstart, align); + spin_lock(&vmap_area_lock); /* XXX: could have a last_hole cache */ n = vmap_area_root.rb_node; -- cgit v1.2.3