[PATCH 03/29] mm: allow PF_MEMALLOC from softirq context
From: Peter Zijlstra <hidden>
Date: 2007-02-21 15:34:30
Also in:
lkml, netdev
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> --- kernel/softirq.c | 3 +++ mm/internal.h | 14 ++++++++------ 2 files changed, 11 insertions(+), 6 deletions(-) Index: linux-2.6-git/mm/internal.h ===================================================================
--- linux-2.6-git.orig/mm/internal.h 2006-12-14 10:02:52.000000000 +0100
+++ linux-2.6-git/mm/internal.h 2006-12-14 10:10:09.000000000 +0100@@ -75,9 +75,10 @@ static int inline gfp_to_alloc_flags(gfp 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; }
@@ -117,9 +118,10 @@ static inline int gfp_to_rank(gfp_t gfp_ */ if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) { - if (!in_interrupt() && - ((current->flags & PF_MEMALLOC) || - unlikely(test_thread_flag(TIF_MEMDIE)))) + if (!in_irq() && (current->flags & PF_MEMALLOC)) + return 0; + else if (!in_interrupt() && + unlikely(test_thread_flag(TIF_MEMDIE))) return 0; }
Index: linux-2.6-git/kernel/softirq.c ===================================================================
--- linux-2.6-git.orig/kernel/softirq.c 2006-12-14 10:02:18.000000000 +0100
+++ linux-2.6-git/kernel/softirq.c 2006-12-14 10:02:52.000000000 +0100@@ -209,6 +209,8 @@ 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);
@@ -247,6 +249,7 @@ restart: account_system_vtime(current); _local_bh_enable(); + current->flags = pflags; } #ifndef __ARCH_HAS_DO_SOFTIRQ
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