From fe5c1c8fb937022820d4c04c89c4e972ee2b9639 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 12 Dec 2016 16:44:20 -0800 Subject: mm: mark all calls into the vmalloc subsystem as potentially sleeping We will take a sleeping lock in later in this series, so this adds the proper safeguards. Change-Id: Iba7efcb690ad584a30ac31cfb7937889bab44e2e Link: http://lkml.kernel.org/r/1479474236-4139-9-git-send-email-hch@lst.de Signed-off-by: Christoph Hellwig Tested-by: Jisheng Zhang Cc: Andrey Ryabinin Cc: Joel Fernandes Cc: Chris Wilson Cc: John Dias Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Git-commit: 5803ed292e63a1bf00722d6655d0229794607183 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Vinayak Menon --- mm/vmalloc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 7e31c5d3b3cb..db37a7208c03 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -413,6 +413,8 @@ 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(); + va = kmalloc_node(sizeof(struct vmap_area), gfp_mask & GFP_RECLAIM_MASK, node); if (unlikely(!va)) @@ -1063,6 +1065,8 @@ void vm_unmap_aliases(void) if (unlikely(!vmap_initialized)) return; + might_sleep(); + for_each_possible_cpu(cpu) { struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu); struct vmap_block *vb; @@ -1106,6 +1110,7 @@ void vm_unmap_ram(const void *mem, unsigned int count) unsigned long addr = (unsigned long)mem; struct vmap_area *va; + might_sleep(); BUG_ON(!addr); BUG_ON(addr < VMALLOC_START); BUG_ON(addr > VMALLOC_END); @@ -1495,6 +1500,8 @@ struct vm_struct *remove_vm_area(const void *addr) { struct vmap_area *va; + might_sleep(); + va = find_vmap_area((unsigned long)addr); if (va && va->flags & VM_VM_AREA) { struct vm_struct *vm = va->vm; -- cgit v1.2.3 From bcfa0a914033438a4e8812496f32f3bd512332a9 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 12 Dec 2016 16:44:23 -0800 Subject: mm: turn vmap_purge_lock into a mutex The purge_lock spinlock causes high latencies with non RT kernel. This has been reported multiple times on lkml [1] [2] and affects applications like audio. This patch replaces it with a mutex to allow preemption while holding the lock. Thanks to Joel Fernandes for the detailed report and analysis as well as an earlier attempt at fixing this issue. [1] http://lists.openwall.net/linux-kernel/2016/03/23/29 [2] https://lkml.org/lkml/2016/10/9/59 Change-Id: I57d4e9c7ce5aeb3273574026da2a8b737ef0b809 Link: http://lkml.kernel.org/r/1479474236-4139-10-git-send-email-hch@lst.de Signed-off-by: Christoph Hellwig Tested-by: Jisheng Zhang Cc: Andrey Ryabinin Cc: Joel Fernandes Cc: Chris Wilson Cc: John Dias Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Git-commit: f9e09977671b618aeb25ddc0d4c9a84d5b5cde9d Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Vinayak Menon --- mm/vmalloc.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index db37a7208c03..30818930331f 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -634,7 +634,7 @@ static atomic_t vmap_lazy_nr = ATOMIC_INIT(0); * by this look, but we want to avoid concurrent calls for performance * reasons and to make the pcpu_get_vm_areas more deterministic. */ -static DEFINE_SPINLOCK(vmap_purge_lock); +static DEFINE_MUTEX(vmap_purge_lock); /* for per-CPU blocks */ static void purge_fragmented_blocks_allcpus(void); @@ -688,9 +688,9 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) */ static void try_purge_vmap_area_lazy(void) { - if (spin_trylock(&vmap_purge_lock)) { + if (mutex_trylock(&vmap_purge_lock)) { __purge_vmap_area_lazy(ULONG_MAX, 0); - spin_unlock(&vmap_purge_lock); + mutex_unlock(&vmap_purge_lock); } } @@ -699,10 +699,10 @@ static void try_purge_vmap_area_lazy(void) */ static void purge_vmap_area_lazy(void) { - spin_lock(&vmap_purge_lock); + mutex_lock(&vmap_purge_lock); purge_fragmented_blocks_allcpus(); __purge_vmap_area_lazy(ULONG_MAX, 0); - spin_unlock(&vmap_purge_lock); + mutex_unlock(&vmap_purge_lock); } /* @@ -1091,11 +1091,11 @@ void vm_unmap_aliases(void) rcu_read_unlock(); } - spin_lock(&vmap_purge_lock); + mutex_lock(&vmap_purge_lock); purge_fragmented_blocks_allcpus(); if (!__purge_vmap_area_lazy(start, end) && flush) flush_tlb_kernel_range(start, end); - spin_unlock(&vmap_purge_lock); + mutex_unlock(&vmap_purge_lock); } EXPORT_SYMBOL_GPL(vm_unmap_aliases); -- cgit v1.2.3