From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <20080220150305.905314000@chello.nl> References: <20080220144610.548202000@chello.nl> Date: Wed, 20 Feb 2008 15:46:15 +0100 From: Peter Zijlstra Subject: [PATCH 05/28] mm: allow PF_MEMALLOC from softirq context Content-Disposition: inline; filename=mm-PF_MEMALLOC-softirq.patch Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, trond.myklebust@fys.uio.no Cc: Peter Zijlstra List-ID: 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. This is needed to allow network softirq packet processing to make use of PF_MEMALLOC. Signed-off-by: Peter Zijlstra --- 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 @@ -1471,9 +1471,10 @@ 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 @@ -213,6 +213,8 @@ 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); @@ -251,6 +253,7 @@ 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 @@ -1497,6 +1497,10 @@ 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 -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org