[PATCH 06/33] mm: allow PF_MEMALLOC from softirq context
From: Peter Zijlstra <hidden>
Date: 2007-10-30 16:25:33
Also in:
linux-mm, lkml
Allow PF_MEMALLOC to be set in softirq context. When running softirqs from a borrowed context save current->flags, ksoftirqd will have its own task_struct. Signed-off-by: Peter Zijlstra <redacted> --- include/linux/sched.h | 4 ++++ kernel/softirq.c | 3 +++ mm/page_alloc.c | 7 ++++--- 3 files changed, 11 insertions(+), 3 deletions(-) Index: linux-2.6/mm/page_alloc.c ===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c@@ -1557,9 +1557,10 @@ int gfp_to_alloc_flags(gfp_t gfp_mask) alloc_flags |= ALLOC_HARDER; if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) { - if (!in_interrupt() && - ((p->flags & PF_MEMALLOC) || - unlikely(test_thread_flag(TIF_MEMDIE)))) + if (!in_irq() && (p->flags & PF_MEMALLOC)) + alloc_flags |= ALLOC_NO_WATERMARKS; + else if (!in_interrupt() && + unlikely(test_thread_flag(TIF_MEMDIE))) alloc_flags |= ALLOC_NO_WATERMARKS; }
Index: linux-2.6/kernel/softirq.c ===================================================================
--- linux-2.6.orig/kernel/softirq.c
+++ linux-2.6/kernel/softirq.c@@ -211,6 +211,8 @@ asmlinkage void __do_softirq(void) __u32 pending; int max_restart = MAX_SOFTIRQ_RESTART; int cpu; + unsigned long pflags = current->flags; + current->flags &= ~PF_MEMALLOC; pending = local_softirq_pending(); account_system_vtime(current);
@@ -249,6 +251,7 @@ restart: account_system_vtime(current); _local_bh_enable(); + tsk_restore_flags(current, pflags, PF_MEMALLOC); } #ifndef __ARCH_HAS_DO_SOFTIRQ
Index: linux-2.6/include/linux/sched.h ===================================================================
--- linux-2.6.orig/include/linux/sched.h
+++ linux-2.6/include/linux/sched.h@@ -1389,6 +1389,10 @@ static inline void put_task_struct(struc #define tsk_used_math(p) ((p)->flags & PF_USED_MATH) #define used_math() tsk_used_math(current) +#define tsk_restore_flags(p, pflags, mask) \ + do { (p)->flags &= ~(mask); \ + (p)->flags |= ((pflags) & (mask)); } while (0) + #ifdef CONFIG_SMP extern int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask); #else --