- one more regression fix: http://patchwork.kernel.org/patch/45707, release 0.4.

[packages/kernel.git] / kernel-regressions.patch

rom ae060e0b7bc071bd73dd5319b93c3344d9e10212 Mon Sep 17 00:00:00 2001
From: Manfred Spraul <manfred@colorfullife.com>
To: torvalds@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Cc: cebbert@redhat.com
Cc: airlied@gmail.com
Cc: akpm@linux-foundation.org
Bcc: manfred@colorfullife.com
Date: Wed, 10 Dec 2008 18:17:06 +0100
Subject: [PATCH] lib/idr.c: Fix bug introduced by RCU fix

The last patch to lib/idr.c caused a bug if idr_get_new_above() was
called on an empty idr:
Usually, nodes stay on the same layer. New layers are added to the top
of the tree.
The exception is idr_get_new_above() on an empty tree: In this case,
the new root node is first added on layer 0, then moved upwards.
p->layer was not updated.

As usual: You shall never rely on the source code comments, they
will only mislead you.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
---
 lib/idr.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/lib/idr.c b/lib/idr.c
index 7a785a0..1c4f928 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -220,8 +220,14 @@ build_up:
 	 */
 	while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) {
 		layers++;
-		if (!p->count)
+		if (!p->count) {
+			/* special case: if the tree is currently empty,
+			 * then we grow the tree by moving the top node
+			 * upwards.
+			 */
+			p->layer++;
 			continue;
+		}
 		if (!(new = get_from_free_list(idp))) {
 			/*
 			 * The allocation failed.  If we built part of
-- 
1.5.6.5

From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Thu, 20 Nov 2008 21:06:21 +0000 (-0500)
Subject: SUNRPC: Fix a performance regression in the RPC authentication code
X-Git-Tag: v2.6.28-rc6~4
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=23918b03060f6e572168fdde1798a905679d2e06

SUNRPC: Fix a performance regression in the RPC authentication code

Fix a regression reported by Max Kellermann whereby kernel profiling
showed that his clients were spending 45% of their time in
rpcauth_lookup_credcache.

It turns out that although his processes had identical uid/gid/groups,
generic_match() was failing to detect this, because the task->group_info
pointers were not shared. This again lead to the creation of a huge number
of identical credentials at the RPC layer.

The regression is fixed by comparing the contents of task->group_info
if the actual pointers are not identical.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/net/sunrpc/auth_generic.c b/net/sunrpc/auth_generic.c
index 744b79f..4028502 100644
--- a/net/sunrpc/auth_generic.c
+++ b/net/sunrpc/auth_generic.c
@@ -133,13 +133,29 @@ static int
 generic_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
 {
 	struct generic_cred *gcred = container_of(cred, struct generic_cred, gc_base);
+	int i;
 
 	if (gcred->acred.uid != acred->uid ||
 	    gcred->acred.gid != acred->gid ||
-	    gcred->acred.group_info != acred->group_info ||
 	    gcred->acred.machine_cred != acred->machine_cred)
-		return 0;
+		goto out_nomatch;
+
+	/* Optimisation in the case where pointers are identical... */
+	if (gcred->acred.group_info == acred->group_info)
+		goto out_match;
+
+	/* Slow path... */
+	if (gcred->acred.group_info->ngroups != acred->group_info->ngroups)
+		goto out_nomatch;
+	for (i = 0; i < gcred->acred.group_info->ngroups; i++) {
+		if (GROUP_AT(gcred->acred.group_info, i) !=
+				GROUP_AT(acred->group_info, i))
+			goto out_nomatch;
+	}
+out_match:
 	return 1;
+out_nomatch:
+	return 0;
 }
 
 void __init rpc_init_generic_auth(void)