From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: [12/17] Virtual Compound page allocation from interrupt context. Date: Tue, 25 Sep 2007 16:42:16 -0700 Message-ID: <20070925234251.981728700@sgi.com> References: <20070925234204.546836393@sgi.com> Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Return-path: Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:36410 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752867AbXIYXmw (ORCPT ); Tue, 25 Sep 2007 19:42:52 -0400 Content-Disposition: inline; filename=vcompound_interrupt_alloc Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org 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 2007-09-24 16:03:49.000000000 -0700 +++ linux-2.6/mm/vmalloc.c 2007-09-24 16:04:32.000000000 -0700 @@ -289,7 +289,6 @@ 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); @@ -314,7 +313,14 @@ 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) --