[PATCH 1/6] mm: change locked_vm's type from unsigned long to atomic64_t
Daniel Jordan
daniel.m.jordan at oracle.com
Wed Apr 3 07:41:53 AEDT 2019
Taking and dropping mmap_sem to modify a single counter, locked_vm, is
overkill when the counter could be synchronized separately.
Make mmap_sem a little less coarse by changing locked_vm to an atomic,
the 64-bit variety to avoid issues with overflow on 32-bit systems.
Signed-off-by: Daniel Jordan <daniel.m.jordan at oracle.com>
Cc: Alan Tull <atull at kernel.org>
Cc: Alexey Kardashevskiy <aik at ozlabs.ru>
Cc: Alex Williamson <alex.williamson at redhat.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Christoph Lameter <cl at linux.com>
Cc: Davidlohr Bueso <dave at stgolabs.net>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Moritz Fischer <mdf at kernel.org>
Cc: Paul Mackerras <paulus at ozlabs.org>
Cc: Wu Hao <hao.wu at intel.com>
Cc: <linux-mm at kvack.org>
Cc: <kvm at vger.kernel.org>
Cc: <kvm-ppc at vger.kernel.org>
Cc: <linuxppc-dev at lists.ozlabs.org>
Cc: <linux-fpga at vger.kernel.org>
Cc: <linux-kernel at vger.kernel.org>
---
arch/powerpc/kvm/book3s_64_vio.c | 14 ++++++++------
arch/powerpc/mm/mmu_context_iommu.c | 15 ++++++++-------
drivers/fpga/dfl-afu-dma-region.c | 18 ++++++++++--------
drivers/vfio/vfio_iommu_spapr_tce.c | 17 +++++++++--------
drivers/vfio/vfio_iommu_type1.c | 10 ++++++----
fs/proc/task_mmu.c | 2 +-
include/linux/mm_types.h | 2 +-
kernel/fork.c | 2 +-
mm/debug.c | 5 +++--
mm/mlock.c | 4 ++--
mm/mmap.c | 18 +++++++++---------
mm/mremap.c | 6 +++---
12 files changed, 61 insertions(+), 52 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index f02b04973710..e7fdb6d10eeb 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -59,32 +59,34 @@ static unsigned long kvmppc_stt_pages(unsigned long tce_pages)
static long kvmppc_account_memlimit(unsigned long stt_pages, bool inc)
{
long ret = 0;
+ s64 locked_vm;
if (!current || !current->mm)
return ret; /* process exited */
down_write(¤t->mm->mmap_sem);
+ locked_vm = atomic64_read(¤t->mm->locked_vm);
if (inc) {
unsigned long locked, lock_limit;
- locked = current->mm->locked_vm + stt_pages;
+ locked = locked_vm + stt_pages;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
ret = -ENOMEM;
else
- current->mm->locked_vm += stt_pages;
+ atomic64_add(stt_pages, ¤t->mm->locked_vm);
} else {
- if (WARN_ON_ONCE(stt_pages > current->mm->locked_vm))
- stt_pages = current->mm->locked_vm;
+ if (WARN_ON_ONCE(stt_pages > locked_vm))
+ stt_pages = locked_vm;
- current->mm->locked_vm -= stt_pages;
+ atomic64_sub(stt_pages, ¤t->mm->locked_vm);
}
pr_debug("[%d] RLIMIT_MEMLOCK KVM %c%ld %ld/%ld%s\n", current->pid,
inc ? '+' : '-',
stt_pages << PAGE_SHIFT,
- current->mm->locked_vm << PAGE_SHIFT,
+ atomic64_read(¤t->mm->locked_vm) << PAGE_SHIFT,
rlimit(RLIMIT_MEMLOCK),
ret ? " - exceeded" : "");
diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c
index e7a9c4f6bfca..8038ac24a312 100644
--- a/arch/powerpc/mm/mmu_context_iommu.c
+++ b/arch/powerpc/mm/mmu_context_iommu.c
@@ -55,30 +55,31 @@ static long mm_iommu_adjust_locked_vm(struct mm_struct *mm,
unsigned long npages, bool incr)
{
long ret = 0, locked, lock_limit;
+ s64 locked_vm;
if (!npages)
return 0;
down_write(&mm->mmap_sem);
-
+ locked_vm = atomic64_read(&mm->locked_vm);
if (incr) {
- locked = mm->locked_vm + npages;
+ locked = locked_vm + npages;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
ret = -ENOMEM;
else
- mm->locked_vm += npages;
+ atomic64_add(npages, &mm->locked_vm);
} else {
- if (WARN_ON_ONCE(npages > mm->locked_vm))
- npages = mm->locked_vm;
- mm->locked_vm -= npages;
+ if (WARN_ON_ONCE(npages > locked_vm))
+ npages = locked_vm;
+ atomic64_sub(npages, &mm->locked_vm);
}
pr_debug("[%d] RLIMIT_MEMLOCK HASH64 %c%ld %ld/%ld\n",
current ? current->pid : 0,
incr ? '+' : '-',
npages << PAGE_SHIFT,
- mm->locked_vm << PAGE_SHIFT,
+ atomic64_read(&mm->locked_vm) << PAGE_SHIFT,
rlimit(RLIMIT_MEMLOCK));
up_write(&mm->mmap_sem);
diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
index e18a786fc943..08132fd9b6b7 100644
--- a/drivers/fpga/dfl-afu-dma-region.c
+++ b/drivers/fpga/dfl-afu-dma-region.c
@@ -45,6 +45,7 @@ void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
static int afu_dma_adjust_locked_vm(struct device *dev, long npages, bool incr)
{
unsigned long locked, lock_limit;
+ s64 locked_vm;
int ret = 0;
/* the task is exiting. */
@@ -53,24 +54,25 @@ static int afu_dma_adjust_locked_vm(struct device *dev, long npages, bool incr)
down_write(¤t->mm->mmap_sem);
+ locked_vm = atomic64_read(¤t->mm->locked_vm);
if (incr) {
- locked = current->mm->locked_vm + npages;
+ locked = locked_vm + npages;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
ret = -ENOMEM;
else
- current->mm->locked_vm += npages;
+ atomic64_add(npages, ¤t->mm->locked_vm);
} else {
- if (WARN_ON_ONCE(npages > current->mm->locked_vm))
- npages = current->mm->locked_vm;
- current->mm->locked_vm -= npages;
+ if (WARN_ON_ONCE(npages > locked_vm))
+ npages = locked_vm;
+ atomic64_sub(npages, ¤t->mm->locked_vm);
}
- dev_dbg(dev, "[%d] RLIMIT_MEMLOCK %c%ld %ld/%ld%s\n", current->pid,
+ dev_dbg(dev, "[%d] RLIMIT_MEMLOCK %c%ld %lld/%lu%s\n", current->pid,
incr ? '+' : '-', npages << PAGE_SHIFT,
- current->mm->locked_vm << PAGE_SHIFT, rlimit(RLIMIT_MEMLOCK),
- ret ? "- exceeded" : "");
+ (s64)atomic64_read(¤t->mm->locked_vm) << PAGE_SHIFT,
+ rlimit(RLIMIT_MEMLOCK), ret ? "- exceeded" : "");
up_write(¤t->mm->mmap_sem);
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 8dbb270998f4..e7d787e5d839 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -36,7 +36,8 @@ static void tce_iommu_detach_group(void *iommu_data,
static long try_increment_locked_vm(struct mm_struct *mm, long npages)
{
- long ret = 0, locked, lock_limit;
+ long ret = 0, lock_limit;
+ s64 locked;
if (WARN_ON_ONCE(!mm))
return -EPERM;
@@ -45,16 +46,16 @@ static long try_increment_locked_vm(struct mm_struct *mm, long npages)
return 0;
down_write(&mm->mmap_sem);
- locked = mm->locked_vm + npages;
+ locked = atomic64_read(&mm->locked_vm) + npages;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
ret = -ENOMEM;
else
- mm->locked_vm += npages;
+ atomic64_add(npages, &mm->locked_vm);
pr_debug("[%d] RLIMIT_MEMLOCK +%ld %ld/%ld%s\n", current->pid,
npages << PAGE_SHIFT,
- mm->locked_vm << PAGE_SHIFT,
+ atomic64_read(&mm->locked_vm) << PAGE_SHIFT,
rlimit(RLIMIT_MEMLOCK),
ret ? " - exceeded" : "");
@@ -69,12 +70,12 @@ static void decrement_locked_vm(struct mm_struct *mm, long npages)
return;
down_write(&mm->mmap_sem);
- if (WARN_ON_ONCE(npages > mm->locked_vm))
- npages = mm->locked_vm;
- mm->locked_vm -= npages;
+ if (WARN_ON_ONCE(npages > atomic64_read(&mm->locked_vm)))
+ npages = atomic64_read(&mm->locked_vm);
+ atomic64_sub(npages, &mm->locked_vm);
pr_debug("[%d] RLIMIT_MEMLOCK -%ld %ld/%ld\n", current->pid,
npages << PAGE_SHIFT,
- mm->locked_vm << PAGE_SHIFT,
+ atomic64_read(&mm->locked_vm) << PAGE_SHIFT,
rlimit(RLIMIT_MEMLOCK));
up_write(&mm->mmap_sem);
}
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 73652e21efec..5b2878697286 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -270,18 +270,19 @@ static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
if (!ret) {
if (npage > 0) {
if (!dma->lock_cap) {
+ s64 locked_vm = atomic64_read(&mm->locked_vm);
unsigned long limit;
limit = task_rlimit(dma->task,
RLIMIT_MEMLOCK) >> PAGE_SHIFT;
- if (mm->locked_vm + npage > limit)
+ if (locked_vm + npage > limit)
ret = -ENOMEM;
}
}
if (!ret)
- mm->locked_vm += npage;
+ atomic64_add(npage, &mm->locked_vm);
up_write(&mm->mmap_sem);
}
@@ -401,6 +402,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
long ret, pinned = 0, lock_acct = 0;
bool rsvd;
dma_addr_t iova = vaddr - dma->vaddr + dma->iova;
+ atomic64_t *locked_vm = ¤t->mm->locked_vm;
/* This code path is only user initiated */
if (!current->mm)
@@ -418,7 +420,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
* pages are already counted against the user.
*/
if (!rsvd && !vfio_find_vpfn(dma, iova)) {
- if (!dma->lock_cap && current->mm->locked_vm + 1 > limit) {
+ if (!dma->lock_cap && atomic64_read(locked_vm) + 1 > limit) {
put_pfn(*pfn_base, dma->prot);
pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__,
limit << PAGE_SHIFT);
@@ -445,7 +447,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
if (!rsvd && !vfio_find_vpfn(dma, iova)) {
if (!dma->lock_cap &&
- current->mm->locked_vm + lock_acct + 1 > limit) {
+ atomic64_read(locked_vm) + lock_acct + 1 > limit) {
put_pfn(pfn, dma->prot);
pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
__func__, limit << PAGE_SHIFT);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 92a91e7816d8..61da4b24d0e0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -58,7 +58,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
swap = get_mm_counter(mm, MM_SWAPENTS);
SEQ_PUT_DEC("VmPeak:\t", hiwater_vm);
SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm);
- SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm);
+ SEQ_PUT_DEC(" kB\nVmLck:\t", atomic64_read(&mm->locked_vm));
SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm));
SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss);
SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 7eade9132f02..5059b99a0827 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -410,7 +410,7 @@ struct mm_struct {
unsigned long hiwater_vm; /* High-water virtual memory usage */
unsigned long total_vm; /* Total pages mapped */
- unsigned long locked_vm; /* Pages that have PG_mlocked set */
+ atomic64_t locked_vm; /* Pages that have PG_mlocked set */
atomic64_t pinned_vm; /* Refcount permanently increased */
unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */
unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */
diff --git a/kernel/fork.c b/kernel/fork.c
index 9dcd18aa210b..56be8cdc7b4a 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -979,7 +979,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
mm->core_state = NULL;
mm_pgtables_bytes_init(mm);
mm->map_count = 0;
- mm->locked_vm = 0;
+ atomic64_set(&mm->locked_vm, 0);
atomic64_set(&mm->pinned_vm, 0);
memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
spin_lock_init(&mm->page_table_lock);
diff --git a/mm/debug.c b/mm/debug.c
index eee9c221280c..b9cd71927d3c 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -136,7 +136,7 @@ void dump_mm(const struct mm_struct *mm)
#endif
"mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
"pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
- "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
+ "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %llx\n"
"pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
"start_code %lx end_code %lx start_data %lx end_data %lx\n"
"start_brk %lx brk %lx start_stack %lx\n"
@@ -167,7 +167,8 @@ void dump_mm(const struct mm_struct *mm)
atomic_read(&mm->mm_count),
mm_pgtables_bytes(mm),
mm->map_count,
- mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
+ mm->hiwater_rss, mm->hiwater_vm, mm->total_vm,
+ (u64)atomic64_read(&mm->locked_vm),
(u64)atomic64_read(&mm->pinned_vm),
mm->data_vm, mm->exec_vm, mm->stack_vm,
mm->start_code, mm->end_code, mm->start_data, mm->end_data,
diff --git a/mm/mlock.c b/mm/mlock.c
index 080f3b36415b..e492a155c51a 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -562,7 +562,7 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
nr_pages = -nr_pages;
else if (old_flags & VM_LOCKED)
nr_pages = 0;
- mm->locked_vm += nr_pages;
+ atomic64_add(nr_pages, &mm->locked_vm);
/*
* vm_flags is protected by the mmap_sem held in write mode.
@@ -687,7 +687,7 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla
if (down_write_killable(¤t->mm->mmap_sem))
return -EINTR;
- locked += current->mm->locked_vm;
+ locked += atomic64_read(¤t->mm->locked_vm);
if ((locked > lock_limit) && (!capable(CAP_IPC_LOCK))) {
/*
* It is possible that the regions requested intersect with
diff --git a/mm/mmap.c b/mm/mmap.c
index 41eb48d9b527..03576c1d530c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1339,7 +1339,7 @@ static inline int mlock_future_check(struct mm_struct *mm,
/* mlock MCL_FUTURE? */
if (flags & VM_LOCKED) {
locked = len >> PAGE_SHIFT;
- locked += mm->locked_vm;
+ locked += atomic64_read(&mm->locked_vm);
lock_limit = rlimit(RLIMIT_MEMLOCK);
lock_limit >>= PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
@@ -1825,7 +1825,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vma == get_gate_vma(current->mm))
vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
else
- mm->locked_vm += (len >> PAGE_SHIFT);
+ atomic64_add(len >> PAGE_SHIFT, &mm->locked_vm);
}
if (file)
@@ -2301,7 +2301,7 @@ static int acct_stack_growth(struct vm_area_struct *vma,
if (vma->vm_flags & VM_LOCKED) {
unsigned long locked;
unsigned long limit;
- locked = mm->locked_vm + grow;
+ locked = atomic64_read(&mm->locked_vm) + grow;
limit = rlimit(RLIMIT_MEMLOCK);
limit >>= PAGE_SHIFT;
if (locked > limit && !capable(CAP_IPC_LOCK))
@@ -2395,7 +2395,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
*/
spin_lock(&mm->page_table_lock);
if (vma->vm_flags & VM_LOCKED)
- mm->locked_vm += grow;
+ atomic64_add(grow, &mm->locked_vm);
vm_stat_account(mm, vma->vm_flags, grow);
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_end = address;
@@ -2475,7 +2475,7 @@ int expand_downwards(struct vm_area_struct *vma,
*/
spin_lock(&mm->page_table_lock);
if (vma->vm_flags & VM_LOCKED)
- mm->locked_vm += grow;
+ atomic64_add(grow, &mm->locked_vm);
vm_stat_account(mm, vma->vm_flags, grow);
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_start = address;
@@ -2796,11 +2796,11 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
/*
* unlock any mlock()ed ranges before detaching vmas
*/
- if (mm->locked_vm) {
+ if (atomic64_read(&mm->locked_vm)) {
struct vm_area_struct *tmp = vma;
while (tmp && tmp->vm_start < end) {
if (tmp->vm_flags & VM_LOCKED) {
- mm->locked_vm -= vma_pages(tmp);
+ atomic64_sub(vma_pages(tmp), &mm->locked_vm);
munlock_vma_pages_all(tmp);
}
@@ -3043,7 +3043,7 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
mm->total_vm += len >> PAGE_SHIFT;
mm->data_vm += len >> PAGE_SHIFT;
if (flags & VM_LOCKED)
- mm->locked_vm += (len >> PAGE_SHIFT);
+ atomic64_add(len >> PAGE_SHIFT, &mm->locked_vm);
vma->vm_flags |= VM_SOFTDIRTY;
return 0;
}
@@ -3115,7 +3115,7 @@ void exit_mmap(struct mm_struct *mm)
up_write(&mm->mmap_sem);
}
- if (mm->locked_vm) {
+ if (atomic64_read(&mm->locked_vm)) {
vma = mm->mmap;
while (vma) {
if (vma->vm_flags & VM_LOCKED)
diff --git a/mm/mremap.c b/mm/mremap.c
index e3edef6b7a12..9a4046bb2875 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -422,7 +422,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
}
if (vm_flags & VM_LOCKED) {
- mm->locked_vm += new_len >> PAGE_SHIFT;
+ atomic64_add(new_len >> PAGE_SHIFT, &mm->locked_vm);
*locked = true;
}
@@ -473,7 +473,7 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr,
if (vma->vm_flags & VM_LOCKED) {
unsigned long locked, lock_limit;
- locked = mm->locked_vm << PAGE_SHIFT;
+ locked = atomic64_read(&mm->locked_vm) << PAGE_SHIFT;
lock_limit = rlimit(RLIMIT_MEMLOCK);
locked += new_len - old_len;
if (locked > lock_limit && !capable(CAP_IPC_LOCK))
@@ -679,7 +679,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
vm_stat_account(mm, vma->vm_flags, pages);
if (vma->vm_flags & VM_LOCKED) {
- mm->locked_vm += pages;
+ atomic64_add(pages, &mm->locked_vm);
locked = true;
new_addr = addr;
}
--
2.21.0
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