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Merge branch 'sysctl' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6 

* 'sysctl' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6:
  SYSCTL: Add a mutex to the page_alloc zone order sysctl
  SYSCTL: Print binary sysctl warnings (nearly) only once
This commit is contained in:
Linus Torvalds 2009-12-24 13:01:29 -08:00
parent 6067d7e4f0 443c6f145d
commit 0b5e2588d8
2 changed files with 37 additions and 5 deletions
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31
kernel/sysctl_binary.c
View File

@ -1417,6 +1417,35 @@ static void deprecated_sysctl_warning(const int *name, int nlen)
return;
}
#define WARN_ONCE_HASH_BITS 8
#define WARN_ONCE_HASH_SIZE (1<<WARN_ONCE_HASH_BITS)
static DECLARE_BITMAP(warn_once_bitmap, WARN_ONCE_HASH_SIZE);
#define FNV32_OFFSET 2166136261U
#define FNV32_PRIME 0x01000193
/*
* Print each legacy sysctl (approximately) only once.
* To avoid making the tables non-const use a external
* hash-table instead.
* Worst case hash collision: 6, but very rarely.
* NOTE! We don't use the SMP-safe bit tests. We simply
* don't care enough.
*/
static void warn_on_bintable(const int *name, int nlen)
{
int i;
u32 hash = FNV32_OFFSET;
for (i = 0; i < nlen; i++)
hash = (hash ^ name[i]) * FNV32_PRIME;
hash %= WARN_ONCE_HASH_SIZE;
if (__test_and_set_bit(hash, warn_once_bitmap))
return;
deprecated_sysctl_warning(name, nlen);
}
static ssize_t do_sysctl(int __user *args_name, int nlen,
void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)
{
@ -1431,7 +1460,7 @@ static ssize_t do_sysctl(int __user *args_name, int nlen,
if (get_user(name[i], args_name + i))
return -EFAULT;
deprecated_sysctl_warning(name, nlen);
warn_on_bintable(name, nlen);
return binary_sysctl(name, nlen, oldval, oldlen, newval, newlen);
}

11
mm/page_alloc.c
View File

@ -2402,13 +2402,14 @@ int numa_zonelist_order_handler(ctl_table *table, int write,
{
char saved_string[NUMA_ZONELIST_ORDER_LEN];
int ret;
static DEFINE_MUTEX(zl_order_mutex);
mutex_lock(&zl_order_mutex);
if (write)
strncpy(saved_string, (char*)table->data,
NUMA_ZONELIST_ORDER_LEN);
strcpy(saved_string, (char*)table->data);
ret = proc_dostring(table, write, buffer, length, ppos);
if (ret)
return ret;
goto out;
if (write) {
int oldval = user_zonelist_order;
if (__parse_numa_zonelist_order((char*)table->data)) {
@ -2421,7 +2422,9 @@ int numa_zonelist_order_handler(ctl_table *table, int write,
} else if (oldval != user_zonelist_order)
build_all_zonelists();
}
return 0;
out:
mutex_unlock(&zl_order_mutex);
return ret;
}