diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-05-05 17:50:24 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-05 20:18:32 +0200 |
| commit | c5078f78b455fbf67ea71442c7e7ca8acf9ff095 (patch) | |
| tree | bdd3b699919f2b23faf13177954e82b570653711 /kernel | |
| parent | 6de6a7b95705b859b61430fa3afa1403034eb3e6 (diff) | |
perf_counter: provide an mlock threshold
Provide a threshold to relax the mlock accounting, increasing usability.
Each counter gets perf_counter_mlock_kb for free.
[ Impact: allow more mmap buffering ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090505155437.112113632@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/perf_counter.c | 15 | ||||
| -rw-r--r-- | kernel/sysctl.c | 8 |
2 files changed, 19 insertions, 4 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 6e6834e0587..2d134273830 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -44,6 +44,7 @@ static atomic_t nr_munmap_tracking __read_mostly; static atomic_t nr_comm_tracking __read_mostly; int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */ +int sysctl_perf_counter_mlock __read_mostly = 128; /* 'free' kb per counter */ /* * Lock for (sysadmin-configurable) counter reservations: @@ -1461,7 +1462,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) if (atomic_dec_and_mutex_lock(&counter->mmap_count, &counter->mmap_mutex)) { - vma->vm_mm->locked_vm -= counter->data->nr_pages + 1; + vma->vm_mm->locked_vm -= counter->data->nr_locked; perf_mmap_data_free(counter); mutex_unlock(&counter->mmap_mutex); } @@ -1480,6 +1481,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) unsigned long nr_pages; unsigned long locked, lock_limit; int ret = 0; + long extra; if (!(vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_WRITE)) return -EINVAL; @@ -1507,8 +1509,12 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) goto unlock; } - locked = vma->vm_mm->locked_vm; - locked += nr_pages + 1; + extra = nr_pages /* + 1 only account the data pages */; + extra -= sysctl_perf_counter_mlock >> (PAGE_SHIFT - 10); + if (extra < 0) + extra = 0; + + locked = vma->vm_mm->locked_vm + extra; lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; lock_limit >>= PAGE_SHIFT; @@ -1524,7 +1530,8 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) goto unlock; atomic_set(&counter->mmap_count, 1); - vma->vm_mm->locked_vm += nr_pages + 1; + vma->vm_mm->locked_vm += extra; + counter->data->nr_locked = extra; unlock: mutex_unlock(&counter->mmap_mutex); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 8203d70928d..3b05c2b088d 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -920,6 +920,14 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = &proc_dointvec, }, + { + .ctl_name = CTL_UNNUMBERED, + .procname = "perf_counter_mlock_kb", + .data = &sysctl_perf_counter_mlock, + .maxlen = sizeof(sysctl_perf_counter_mlock), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, #endif /* * NOTE: do not add new entries to this table unless you have read |