Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932715AbdCGP5N (ORCPT ); Tue, 7 Mar 2017 10:57:13 -0500 Received: from mail-wr0-f193.google.com ([209.85.128.193]:35193 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755571AbdCGP4k (ORCPT ); Tue, 7 Mar 2017 10:56:40 -0500 From: Michal Hocko To: Cc: Vlastimil Babka , Johannes Weiner , Mel Gorman , Andrew Morton , LKML , Michal Hocko Subject: [RFC PATCH 4/4] mm: kvmalloc support __GFP_RETRY_MAYFAIL for all sizes Date: Tue, 7 Mar 2017 16:48:43 +0100 Message-Id: <20170307154843.32516-5-mhocko@kernel.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170307154843.32516-1-mhocko@kernel.org> References: <20170307154843.32516-1-mhocko@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2002 Lines: 48 From: Michal Hocko Now that __GFP_RETRY_MAYFAIL has a reasonable semantic regardless of the request size we can drop the hackish implementation for !costly orders. __GFP_RETRY_MAYFAIL retries as long as the reclaim makes a forward progress and backs of when we are out of memory for the requested size. Therefore we do not need to enforce__GFP_NORETRY for !costly orders just to silent the oom killer anymore. Signed-off-by: Michal Hocko --- mm/util.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/mm/util.c b/mm/util.c index 885a78d1941b..359d80333301 100644 --- a/mm/util.c +++ b/mm/util.c @@ -339,9 +339,9 @@ EXPORT_SYMBOL(vm_mmap); * Uses kmalloc to get the memory but if the allocation fails then falls back * to the vmalloc allocator. Use kvfree for freeing the memory. * - * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported. __GFP_RETRY_MAYFAIL - * is supported only for large (>32kB) allocations, and it should be used only if - * kmalloc is preferable to the vmalloc fallback, due to visible performance drawbacks. + * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported. + * __GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is + * preferable to the vmalloc fallback, due to visible performance drawbacks. * * Any use of gfp flags outside of GFP_KERNEL should be consulted with mm people. */ @@ -363,13 +363,7 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) if (size > PAGE_SIZE) { kmalloc_flags |= __GFP_NOWARN; - /* - * We have to override __GFP_RETRY_MAYFAIL by __GFP_NORETRY for !costly - * requests because there is no other way to tell the allocator - * that we want to fail rather than retry endlessly. - */ - if (!(kmalloc_flags & __GFP_RETRY_MAYFAIL) || - (size <= PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) + if (!(kmalloc_flags & __GFP_RETRY_MAYFAIL)) kmalloc_flags |= __GFP_NORETRY; } -- 2.11.0