* + h8300-select-generic-atomic64_t-support.patch added to -mm tree
@ 2012-08-20 21:21 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2012-08-20 21:21 UTC (permalink / raw
To: mm-commits; +Cc: fengguang.wu, ebiederm, ysato
The patch titled
Subject: h8300: select generic atomic64_t support
has been added to the -mm tree. Its filename is
h8300-select-generic-atomic64_t-support.patch
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From: Fengguang Wu <fengguang.wu@intel.com>
Subject: h8300: select generic atomic64_t support
Rationales from Eric:
So I just looked a little deeper and it appears architectures that do
not support atomic64_t are broken.
The generic atomic64 support came in 2009 to support the perf subsystem
with the expectation that all architectures would implement atomic64
support.
Furthermore upon inspection of the kernel atomic64_t is used in a fair
number of places beyond the performance counters:
block/blk-cgroup.c
drivers/acpi/apei/
drivers/block/rbd.c
drivers/crypto/nx/nx.h
drivers/gpu/drm/radeon/radeon.h
drivers/infiniband/hw/ipath/
drivers/infiniband/hw/qib/
drivers/staging/octeon/
fs/xfs/
include/linux/perf_event.h
include/net/netfilter/nf_conntrack_acct.h
kernel/events/
kernel/trace/
net/mac80211/key.h
net/rds/
The block control group, infiniband, xfs, crypto, 802.11, netfilter.
Nothing quite so fundamental as fs/namespace.c but definitely in
multiplatform-code that should work, and is already broken on those
architecutres.
Looking at the implementation of atomic64_add_return in lib/atomic64.c the
code looks as efficient as these kinds of things get.
Which leads me to the conclusion that we need atomic64 support on all
architectures.
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
arch/h8300/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff -puN arch/h8300/Kconfig~h8300-select-generic-atomic64_t-support arch/h8300/Kconfig
--- a/arch/h8300/Kconfig~h8300-select-generic-atomic64_t-support
+++ a/arch/h8300/Kconfig
@@ -3,6 +3,7 @@ config H8300
default y
select HAVE_IDE
select HAVE_GENERIC_HARDIRQS
+ select GENERIC_ATOMIC64
select ARCH_WANT_IPC_PARSE_VERSION
select GENERIC_IRQ_SHOW
select GENERIC_CPU_DEVICES
_
Patches currently in -mm which might be from fengguang.wu@intel.com are
origin.patch
linux-next.patch
alpha-redefine-atomic_init-and-atomic64_init-to-drop-the-casts.patch
h8300-select-generic-atomic64_t-support.patch
mm-fix-nonuniform-page-status-when-writing-new-file-with-small-buffer.patch
mm-fix-nonuniform-page-status-when-writing-new-file-with-small-buffer-fix.patch
mm-fix-nonuniform-page-status-when-writing-new-file-with-small-buffer-fix-fix.patch
rbtree-performance-and-correctness-test-fix.patch
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2012-08-20 21:21 + h8300-select-generic-atomic64_t-support.patch added to -mm tree akpm
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