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From: Christoph Lameter <cl@linux.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>,
	torvalds@linux-foundation.org, Andi Kleen <andi@firstfloor.org>,
	tj@kernel.org, Metathronius Galabant <m.galabant@googlemail.com>,
	Matt Mackall <mpm@selenic.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Adrian Drzewiecki <z@drze.net>,
	linux-mm@kvack.org
Subject: [slub rfc1 02/12] slub: Remove useless statements in __slab_alloc
Date: Fri, 02 Sep 2011 15:46:59 -0500	[thread overview]
Message-ID: <20110902204740.288877218@linux.com> (raw)
In-Reply-To: 20110902204657.105194589@linux.com

[-- Attachment #1: remove_useless_page_null --]
[-- Type: text/plain, Size: 1458 bytes --]

Two statements in __slab_alloc() do not have any effect.

1. c->page is already set to NULL by deactivate_slab() called right before.

2. gfpflags are masked in new_slab() before being passed to the page
   allocator. There is no need to mask gfpflags in __slab_alloc in particular
   since most frequent processing in __slab_alloc does not require the use of a
   gfpmask.

Cc: torvalds@linux-foundation.org
Signed-off-by: Christoph Lameter <cl@linux.com>

---
 mm/slub.c |    4 ----
 1 file changed, 4 deletions(-)

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c	2011-08-01 11:03:15.000000000 -0500
+++ linux-2.6/mm/slub.c	2011-08-01 11:04:06.385859038 -0500
@@ -2064,9 +2064,6 @@ static void *__slab_alloc(struct kmem_ca
 	c = this_cpu_ptr(s->cpu_slab);
 #endif
 
-	/* We handle __GFP_ZERO in the caller */
-	gfpflags &= ~__GFP_ZERO;
-
 	page = c->page;
 	if (!page)
 		goto new_slab;
@@ -2163,7 +2160,6 @@ debug:
 
 	c->freelist = get_freepointer(s, object);
 	deactivate_slab(s, c);
-	c->page = NULL;
 	c->node = NUMA_NO_NODE;
 	local_irq_restore(flags);
 	return object;

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  parent reply	other threads:[~2011-09-02 20:47 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-02 20:46 [slub rfc1 00/12] slub: RFC lockless allocation paths V1 Christoph Lameter
2011-09-02 20:46 ` [slub rfc1 01/12] slub: free slabs without holding locks (V2) Christoph Lameter
2011-09-02 20:46 ` Christoph Lameter [this message]
2011-09-02 20:47 ` [slub rfc1 03/12] slub: Get rid of the node field Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 04/12] slub: Separate out kmem_cache_cpu processing from deactivate_slab Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 05/12] slub: Extract get_freelist from __slab_alloc Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 06/12] slub: Use freelist instead of "object" in __slab_alloc Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 07/12] slub: pass page to node_match() instead of kmem_cache_cpu structure Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 08/12] slub: enable use of deactivate_slab with interrupts on Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 09/12] slub: Run deactivate_slab with interrupts enabled Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 10/12] slub: Enable use of get_partial " Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 11/12] slub: Remove kmem_cache_cpu dependency from acquire slab Christoph Lameter
2011-09-02 20:47 ` [slub rfc1 12/12] slub: Drop page field from kmem_cache_cpu Christoph Lameter

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