PF_MEM_NOWAIT - will make allocations fail before blocking. This is usefull
to convert process behaviour to non-blocking.
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Mike Christie <[email protected]>
---
include/linux/sched.h | 1 +
kernel/softirq.c | 4 ++--
mm/internal.h | 11 ++++++++++-
mm/page_alloc.c | 4 ++--
4 files changed, 15 insertions(+), 5 deletions(-)
Index: linux-2.6-git/include/linux/sched.h
===================================================================
--- linux-2.6-git.orig/include/linux/sched.h 2007-03-26 12:03:07.000000000 +0200
+++ linux-2.6-git/include/linux/sched.h 2007-03-26 12:03:09.000000000 +0200
@@ -1158,6 +1158,7 @@ static inline void put_task_struct(struc
#define PF_SPREAD_SLAB 0x02000000 /* Spread some slab caches over cpuset */
#define PF_MEMPOLICY 0x10000000 /* Non-default NUMA mempolicy */
#define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */
+#define PF_MEM_NOWAIT 0x40000000 /* Make allocations fail instead of block */
/*
* Only the _current_ task can read/write to tsk->flags, but other
Index: linux-2.6-git/mm/page_alloc.c
===================================================================
--- linux-2.6-git.orig/mm/page_alloc.c 2007-03-26 12:03:07.000000000 +0200
+++ linux-2.6-git/mm/page_alloc.c 2007-03-26 12:03:09.000000000 +0200
@@ -1234,11 +1234,11 @@ struct page * fastcall
__alloc_pages(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist)
{
- const gfp_t wait = gfp_mask & __GFP_WAIT;
+ struct task_struct *p = current;
+ const bool wait = gfp_wait(gfp_mask);
struct zone **z;
struct page *page;
struct reclaim_state reclaim_state;
- struct task_struct *p = current;
int do_retry;
int alloc_flags;
int did_some_progress;
Index: linux-2.6-git/mm/internal.h
===================================================================
--- linux-2.6-git.orig/mm/internal.h 2007-03-26 12:03:07.000000000 +0200
+++ linux-2.6-git/mm/internal.h 2007-03-26 12:03:09.000000000 +0200
@@ -46,6 +46,15 @@ extern void fastcall __init __free_pages
#define ALLOC_NO_WATERMARKS 0x20 /* don't check watermarks at all */
#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
+static bool inline gfp_wait(gfp_t gfp_mask)
+{
+ bool wait = gfp_mask & __GFP_WAIT;
+ if (wait && !in_irq() && (current->flags & PF_MEM_NOWAIT))
+ wait = false;
+
+ return wait;
+}
+
/*
* get the deepest reaching allocation flags for the given gfp_mask
*/
@@ -53,7 +62,7 @@ static int inline gfp_to_alloc_flags(gfp
{
struct task_struct *p = current;
int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
- const gfp_t wait = gfp_mask & __GFP_WAIT;
+ const bool wait = gfp_wait(gfp_mask);
/*
* The caller may dip into page reserves a bit more if the caller
Index: linux-2.6-git/kernel/softirq.c
===================================================================
--- linux-2.6-git.orig/kernel/softirq.c 2007-03-26 12:03:07.000000000 +0200
+++ linux-2.6-git/kernel/softirq.c 2007-03-26 12:12:58.000000000 +0200
@@ -211,7 +211,7 @@ asmlinkage void __do_softirq(void)
int max_restart = MAX_SOFTIRQ_RESTART;
int cpu;
unsigned long pflags = current->flags;
- current->flags &= ~PF_MEMALLOC;
+ current->flags &= ~(PF_MEMALLOC|PF_MEM_NOWAIT);
pending = local_softirq_pending();
account_system_vtime(current);
@@ -250,7 +250,7 @@ restart:
account_system_vtime(current);
_local_bh_enable();
- tsk_restore_flags(current, pflags, PF_MEMALLOC);
+ tsk_restore_flags(current, pflags, (PF_MEMALLOC|PF_MEM_NOWAIT));
}
#ifndef __ARCH_HAS_DO_SOFTIRQ
--
-
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