From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: [PATCH 07/30] mm: allow PF_MEMALLOC from softirq context Date: Thu, 24 Jul 2008 16:00:49 +0200 Message-ID: <20080724141529.785703247@chello.nl> References: <20080724140042.408642539@chello.nl> To: Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, trond.myklebust@fy Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:46475 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753643AbYGXOm4 (ORCPT ); Thu, 24 Jul 2008 10:42:56 -0400 Content-Disposition: inline; filename=mm-PF_MEMALLOC-softirq.patch Sender: netdev-owner@vger.kernel.org List-ID: Allow PF_MEMALLOC to be set in softirq context. This is needed to allow network softirq packet processing to make use of PF_MEMALLOC. Signed-off-by: Peter Zijlstra --- include/linux/sched.h | 7 +++++++ kernel/softirq.c | 3 +++ mm/page_alloc.c | 7 ++++--- 3 files changed, 14 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 @@ -1449,9 +1449,10 @@ 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 @@ -1533,6 +1533,13 @@ static inline void put_task_struct(struc #define tsk_used_math(p) ((p)->flags & PF_USED_MATH) #define used_math() tsk_used_math(current) +static inline void tsk_restore_flags(struct task_struct *p, + unsigned long pflags, unsigned long mask) +{ + p->flags &= ~mask; + p->flags |= pflags & mask; +} + #ifdef CONFIG_SMP extern int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask); --