From: Christoph Lameter <cl@linux.com>
To: Tejun Heo <tj@kernel.org>
Cc: akpm@linuxfoundation.org, rostedt@goodmis.org,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Alex Shi <alex.shi@intel.com>
Subject: [PATCH 3/6] mm: Use raw_cpu ops for determining current NUMA node
Date: Tue, 15 Oct 2013 12:47:25 -0500 [thread overview]
Message-ID: <20131015174746.244538146@linux.com> (raw)
In-Reply-To: 20131015174722.615394057@linux.com
[-- Attachment #1: preempt_fix_numa_node --]
[-- Type: text/plain, Size: 4423 bytes --]
With the preempt checking logic for __this_cpu_ops we will get false
positives from locations in the code that use numa_node_id.
Before the __this_cpu ops where introduced there were
no checks for preemption present either. smp_raw_processor_id()
was used. See http://www.spinics.net/lists/linux-numa/msg00641.html
Therefore we need to use raw_cpu_read here to avoid false postives.
Note that this issue has been discussed in prior years.
If the process changes nodes after retrieving the current numa node then
that is acceptable since most uses of numa_node etc are for optimization
and not for correctness.
Some sample traces:
__this_cpu_read operation in preemptible [00000000] code: login/1456
caller is __this_cpu_preempt_check+0x2b/0x2d
CPU: 0 PID: 1456 Comm: login Not tainted 3.12.0-rc4-cl-00062-g2fe80d3-dirty #185
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
000000000000013c ffff88001f31ba58 ffffffff8147cf5e ffff88001f31bfd8
ffff88001f31ba88 ffffffff8127eea9 0000000000000000 ffff88001f3975c0
00000000f7707000 ffff88001f3975c0 ffff88001f31bac0 ffffffff8127eeef
Call Trace:
[<ffffffff8147cf5e>] dump_stack+0x4e/0x82
[<ffffffff8127eea9>] check_preemption_disabled+0xc5/0xe0
[<ffffffff8127eeef>] __this_cpu_preempt_check+0x2b/0x2d
[<ffffffff81030ff5>] ? show_stack+0x3b/0x3d
[<ffffffff810ebee3>] get_task_policy+0x1d/0x49
[<ffffffff810ed705>] get_vma_policy+0x14/0x76
[<ffffffff810ed8ff>] alloc_pages_vma+0x35/0xff
[<ffffffff810dad97>] handle_mm_fault+0x290/0x73b
[<ffffffff810503da>] __do_page_fault+0x3fe/0x44d
[<ffffffff8109b360>] ? trace_hardirqs_on_caller+0x142/0x19e
[<ffffffff8109b3c9>] ? trace_hardirqs_on+0xd/0xf
[<ffffffff81278bed>] ? trace_hardirqs_off_thunk+0x3a/0x3c
[<ffffffff810be97f>] ? find_get_pages_contig+0x18e/0x18e
[<ffffffff810be97f>] ? find_get_pages_contig+0x18e/0x18e
[<ffffffff81050451>] do_page_fault+0x9/0xc
[<ffffffff81483602>] page_fault+0x22/0x30
[<ffffffff810be97f>] ? find_get_pages_contig+0x18e/0x18e
[<ffffffff810be97f>] ? find_get_pages_contig+0x18e/0x18e
[<ffffffff810be4c3>] ? file_read_actor+0x3a/0x15a
[<ffffffff810be97f>] ? find_get_pages_contig+0x18e/0x18e
[<ffffffff810bffab>] generic_file_aio_read+0x38e/0x624
[<ffffffff810f6d69>] do_sync_read+0x54/0x73
[<ffffffff810f7890>] vfs_read+0x9d/0x12a
[<ffffffff810f7a59>] SyS_read+0x47/0x7e
[<ffffffff81484f21>] cstar_dispatch+0x7/0x23
caller is __this_cpu_preempt_check+0x2b/0x2d
CPU: 0 PID: 1456 Comm: login Not tainted 3.12.0-rc4-cl-00062-g2fe80d3-dirty #185
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
00000000000000e8 ffff88001f31bbf8 ffffffff8147cf5e ffff88001f31bfd8
ffff88001f31bc28 ffffffff8127eea9 ffffffff823c5c40 00000000000213da
0000000000000000 0000000000000000 ffff88001f31bc60 ffffffff8127eeef
Call Trace:
[<ffffffff8147cf5e>] dump_stack+0x4e/0x82
[<ffffffff8127eea9>] check_preemption_disabled+0xc5/0xe0
[<ffffffff8127eeef>] __this_cpu_preempt_check+0x2b/0x2d
[<ffffffff810e006e>] ? install_special_mapping+0x11/0xe4
[<ffffffff810ec8a8>] alloc_pages_current+0x8f/0xbc
[<ffffffff810bec6b>] __page_cache_alloc+0xb/0xd
[<ffffffff810c7e90>] __do_page_cache_readahead+0xf4/0x219
[<ffffffff810c7e0e>] ? __do_page_cache_readahead+0x72/0x219
[<ffffffff810c827c>] ra_submit+0x1c/0x20
[<ffffffff810c850c>] ondemand_readahead+0x28c/0x2b4
[<ffffffff810c85e9>] page_cache_sync_readahead+0x38/0x3a
[<ffffffff810bfe7e>] generic_file_aio_read+0x261/0x624
[<ffffffff810f6d69>] do_sync_read+0x54/0x73
[<ffffffff810f7890>] vfs_read+0x9d/0x12a
[<ffffffff810f7a59>] SyS_read+0x47/0x7e
[<ffffffff81484f21>] cstar_dispatch+0x7/0x23
CC: linux-mm@kvack.org
Cc: Alex Shi <alex.shi@intel.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Index: linux/include/linux/topology.h
===================================================================
--- linux.orig/include/linux/topology.h 2013-09-24 11:29:51.000000000 -0500
+++ linux/include/linux/topology.h 2013-09-24 11:30:18.893831971 -0500
@@ -182,7 +182,7 @@ DECLARE_PER_CPU(int, numa_node);
/* Returns the number of the current Node. */
static inline int numa_node_id(void)
{
- return __this_cpu_read(numa_node);
+ return raw_cpu_read(numa_node);
}
#endif
@@ -239,7 +239,7 @@ static inline void set_numa_mem(int node
/* Returns the number of the nearest Node with memory */
static inline int numa_mem_id(void)
{
- return __this_cpu_read(_numa_mem_);
+ return raw_cpu_read(_numa_mem_);
}
#endif
next prev parent reply other threads:[~2013-10-15 17:54 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-15 17:47 [PATCH 0/6] percpu: Implement Preemption checks for __this_cpu operations V4b Christoph Lameter
2013-10-15 17:47 ` [PATCH 1/6] net: ip4_datagram_connect: Use correct form of statistics update Christoph Lameter
2013-10-15 18:36 ` Eric Dumazet
2013-10-16 6:09 ` Ingo Molnar
2013-10-16 8:35 ` Peter Zijlstra
2013-10-16 9:14 ` Eric Dumazet
2013-10-16 9:26 ` Ingo Molnar
2013-10-16 14:27 ` Christoph Lameter
2013-10-16 14:37 ` Eric Dumazet
2013-10-15 17:47 ` [PATCH 2/6] percpu: Add raw_cpu_ops Christoph Lameter
2013-10-15 17:47 ` Christoph Lameter [this message]
2013-10-16 8:38 ` [PATCH 3/6] mm: Use raw_cpu ops for determining current NUMA node Peter Zijlstra
2013-10-16 14:22 ` Christoph Lameter
2013-10-15 17:47 ` [PATCH 4/6] Use raw_cpu_write for initialization of per cpu refcount Christoph Lameter
2013-10-16 8:43 ` Peter Zijlstra
2013-10-15 17:47 ` [PATCH 5/6] net: __this_cpu_inc in route.c Christoph Lameter
2013-10-16 8:46 ` Peter Zijlstra
2013-10-16 9:22 ` Eric Dumazet
2013-10-16 10:25 ` Peter Zijlstra
2013-10-16 15:07 ` Christoph Lameter
2013-10-15 17:47 ` [PATCH 6/6] percpu: Add preemption checks to __this_cpu ops Christoph Lameter
2013-10-16 8:49 ` Peter Zijlstra
2013-10-16 15:09 ` Christoph Lameter
2013-10-16 15:36 ` Peter Zijlstra
2013-10-16 15:55 ` Christoph Lameter
2013-10-16 16:25 ` Peter Zijlstra
2013-10-16 16:52 ` Steven Rostedt
2013-10-16 17:11 ` Peter Zijlstra
2013-10-16 17:39 ` Steven Rostedt
2013-10-16 18:38 ` Peter Zijlstra
2013-10-17 19:22 ` Christoph Lameter
2013-10-17 21:13 ` Peter Zijlstra
[not found] <20131011175518.634285474@linux.com>
2013-10-11 17:54 ` [PATCH 3/6] mm: Use raw_cpu ops for determining current NUMA node Christoph Lameter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20131015174746.244538146@linux.com \
--to=cl@linux.com \
--cc=akpm@linuxfoundation.org \
--cc=alex.shi@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox