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Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (49 commits)
  perfcounter: Handle some IO return values
  perf_counter: Push perf_sample_data through the swcounter code
  perf_counter tools: Define and use our own u64, s64 etc. definitions
  perf_counter: Close race in perf_lock_task_context()
  perf_counter, x86: Improve interactions with fast-gup
  perf_counter: Simplify and fix task migration counting
  perf_counter tools: Add a data file header
  perf_counter: Update userspace callchain sampling uses
  perf_counter: Make callchain samples extensible
  perf report: Filter to parent set by default
  perf_counter tools: Handle lost events
  perf_counter: Add event overlow handling
  fs: Provide empty .set_page_dirty() aop for anon inodes
  perf_counter: tools: Makefile tweaks for 64-bit powerpc
  perf_counter: powerpc: Add processor back-end for MPC7450 family
  perf_counter: powerpc: Make powerpc perf_counter code safe for 32-bit kernels
  perf_counter: powerpc: Change how processor-specific back-ends get selected
  perf_counter: powerpc: Use unsigned long for register and constraint values
  perf_counter: powerpc: Enable use of software counters on 32-bit powerpc
  perf_counter tools: Add and use isprint()
  ...
This commit is contained in:
Linus Torvalds
2009-06-20 11:29:32 -07:00
parent 1eb51c33b2 eadc84cc01
commit 12e24f34cb
40 changed files with 2327 additions and 898 deletions
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58
arch/x86/mm/gup.c
View File

@@ -14,7 +14,7 @@
static inline pte_t gup_get_pte(pte_t *ptep)
{
#ifndef CONFIG_X86_PAE
return *ptep;
return ACCESS_ONCE(*ptep);
#else
/*
* With get_user_pages_fast, we walk down the pagetables without taking
@@ -219,6 +219,62 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
return 1;
}
/*
* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
* back to the regular GUP.
*/
int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages)
{
struct mm_struct *mm = current->mm;
unsigned long addr, len, end;
unsigned long next;
unsigned long flags;
pgd_t *pgdp;
int nr = 0;
start &= PAGE_MASK;
addr = start;
len = (unsigned long) nr_pages << PAGE_SHIFT;
end = start + len;
if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
(void __user *)start, len)))
return 0;
/*
* XXX: batch / limit 'nr', to avoid large irq off latency
* needs some instrumenting to determine the common sizes used by
* important workloads (eg. DB2), and whether limiting the batch size
* will decrease performance.
*
* It seems like we're in the clear for the moment. Direct-IO is
* the main guy that batches up lots of get_user_pages, and even
* they are limited to 64-at-a-time which is not so many.
*/
/*
* This doesn't prevent pagetable teardown, but does prevent
* the pagetables and pages from being freed on x86.
*
* So long as we atomically load page table pointers versus teardown
* (which we do on x86, with the above PAE exception), we can follow the
* address down to the the page and take a ref on it.
*/
local_irq_save(flags);
pgdp = pgd_offset(mm, addr);
do {
pgd_t pgd = *pgdp;
next = pgd_addr_end(addr, end);
if (pgd_none(pgd))
break;
if (!gup_pud_range(pgd, addr, next, write, pages, &nr))
break;
} while (pgdp++, addr = next, addr != end);
local_irq_restore(flags);
return nr;
}
/**
* get_user_pages_fast() - pin user pages in memory
* @start: starting user address