From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <20071004040005.396698805@sgi.com> References: <20071004035935.042951211@sgi.com> Date: Wed, 03 Oct 2007 20:59:51 -0700 From: Christoph Lameter Subject: [16/18] Virtual Compound page allocation from interrupt context. Content-Disposition: inline; filename=vcompound_interrupt_alloc Sender: owner-linux-mm@kvack.org Return-Path: To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: In an interrupt context we cannot wait for the vmlist_lock in __get_vm_area_node(). So use a trylock instead. If the trylock fails then the atomic allocation will fail and subsequently be retried. This only works because the flush_cache_vunmap in use for allocation is never performing any IPIs in contrast to flush_tlb_... in use for freeing. flush_cache_vunmap is only used on architectures with a virtually mapped cache (xtensa, pa-risc). [Note: Nick Piggin is working on a scheme to make this simpler by no longer requiring flushes] Signed-off-by: Christoph Lameter --- mm/vmalloc.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) Index: linux-2.6/mm/vmalloc.c =================================================================== --- linux-2.6.orig/mm/vmalloc.c 2007-10-03 16:21:10.000000000 -0700 +++ linux-2.6/mm/vmalloc.c 2007-10-03 16:25:17.000000000 -0700 @@ -177,7 +177,6 @@ static struct vm_struct *__get_vm_area_n unsigned long align = 1; unsigned long addr; - BUG_ON(in_interrupt()); if (flags & VM_IOREMAP) { int bit = fls(size); @@ -202,7 +201,14 @@ static struct vm_struct *__get_vm_area_n */ size += PAGE_SIZE; - write_lock(&vmlist_lock); + if (gfp_mask & __GFP_WAIT) + write_lock(&vmlist_lock); + else { + if (!write_trylock(&vmlist_lock)) { + kfree(area); + return NULL; + } + } for (p = &vmlist; (tmp = *p) != NULL ;p = &tmp->next) { if ((unsigned long)tmp->addr < addr) { if((unsigned long)tmp->addr + tmp->size >= addr) -- -- 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