Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932334Ab2KMRVL (ORCPT ); Tue, 13 Nov 2012 12:21:11 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:65052 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755402Ab2KMRPI (ORCPT ); Tue, 13 Nov 2012 12:15:08 -0500 From: Ingo Molnar To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Paul Turner , Lee Schermerhorn , Christoph Lameter , Rik van Riel , Mel Gorman , Andrew Morton , Andrea Arcangeli , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Lee Schermerhorn Subject: [PATCH 12/31] mm/mpol: Add MPOL_MF_NOOP Date: Tue, 13 Nov 2012 18:13:35 +0100 Message-Id: <1352826834-11774-13-git-send-email-mingo@kernel.org> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1352826834-11774-1-git-send-email-mingo@kernel.org> References: <1352826834-11774-1-git-send-email-mingo@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3347 Lines: 95 From: Lee Schermerhorn This patch augments the MPOL_MF_LAZY feature by adding a "NOOP" policy to mbind(). When the NOOP policy is used with the 'MOVE and 'LAZY flags, mbind() will map the pages PROT_NONE so that they will be migrated on the next touch. This allows an application to prepare for a new phase of operation where different regions of shared storage will be assigned to worker threads, w/o changing policy. Note that we could just use "default" policy in this case. However, this also allows an application to request that pages be migrated, only if necessary, to follow any arbitrary policy that might currently apply to a range of pages, without knowing the policy, or without specifying multiple mbind()s for ranges with different policies. [ Bug in early version of mpol_parse_str() reported by Fengguang Wu. ] Bug-Reported-by: Reported-by: Fengguang Wu Signed-off-by: Lee Schermerhorn Reviewed-by: Rik van Riel Cc: Andrew Morton Cc: Linus Torvalds Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- include/uapi/linux/mempolicy.h | 1 + mm/mempolicy.c | 11 ++++++----- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h index 3e835c9..d23dca8 100644 --- a/include/uapi/linux/mempolicy.h +++ b/include/uapi/linux/mempolicy.h @@ -21,6 +21,7 @@ enum { MPOL_BIND, MPOL_INTERLEAVE, MPOL_LOCAL, + MPOL_NOOP, /* retain existing policy for range */ MPOL_MAX, /* always last member of enum */ }; diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 72f50ba..c7c7c86 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -251,10 +251,10 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, pr_debug("setting mode %d flags %d nodes[0] %lx\n", mode, flags, nodes ? nodes_addr(*nodes)[0] : -1); - if (mode == MPOL_DEFAULT) { + if (mode == MPOL_DEFAULT || mode == MPOL_NOOP) { if (nodes && !nodes_empty(*nodes)) return ERR_PTR(-EINVAL); - return NULL; /* simply delete any existing policy */ + return NULL; } VM_BUG_ON(!nodes); @@ -1146,7 +1146,7 @@ static long do_mbind(unsigned long start, unsigned long len, if (start & ~PAGE_MASK) return -EINVAL; - if (mode == MPOL_DEFAULT) + if (mode == MPOL_DEFAULT || mode == MPOL_NOOP) flags &= ~MPOL_MF_STRICT; len = (len + PAGE_SIZE - 1) & PAGE_MASK; @@ -2407,7 +2407,8 @@ static const char * const policy_modes[] = [MPOL_PREFERRED] = "prefer", [MPOL_BIND] = "bind", [MPOL_INTERLEAVE] = "interleave", - [MPOL_LOCAL] = "local" + [MPOL_LOCAL] = "local", + [MPOL_NOOP] = "noop", /* should not actually be used */ }; @@ -2458,7 +2459,7 @@ int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context) break; } } - if (mode >= MPOL_MAX) + if (mode >= MPOL_MAX || mode == MPOL_NOOP) goto out; switch (mode) { -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/