lkml.org 
[lkml]   [2018]   [Oct]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:x86/urgent] x86/numa_emulation: Fix uniform-split numa emulation
    Commit-ID:  c6ee7a548e2c291398b4f32c1f741c66b9f98e1c
    Gitweb: https://git.kernel.org/tip/c6ee7a548e2c291398b4f32c1f741c66b9f98e1c
    Author: Dave Jiang <dave.jiang@intel.com>
    AuthorDate: Thu, 25 Oct 2018 13:26:45 -0700
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Tue, 30 Oct 2018 11:36:43 +0100

    x86/numa_emulation: Fix uniform-split numa emulation

    The numa_emulation() routine in the 'uniform' case walks through all the
    physical 'memblk' instances and divides them into N emulated nodes with
    split_nodes_size_interleave_uniform(). As each physical node is consumed it
    is removed from the physical memblk array in the numa_remove_memblk_from()
    helper.

    Since split_nodes_size_interleave_uniform() handles advancing the array as
    the 'memblk' is consumed it is expected that the base of the array is
    always specified as the argument.

    Otherwise, on multi-socket (> 2) configurations the uniform-split
    capability can generate an invalid numa configuration leading to boot
    failures with signatures like the following:

    rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
    Sending NMI from CPU 0 to CPUs 2:
    NMI backtrace for cpu 2
    CPU: 2 PID: 1332 Comm: pgdatinit0 Not tainted 4.19.0-rc8-next-20181019-baseline #59
    RIP: 0010:__init_single_page.isra.74+0x81/0x90
    [..]
    Call Trace:
    deferred_init_pages+0xaa/0xe3
    deferred_init_memmap+0x18f/0x318
    kthread+0xf8/0x130
    ? deferred_free_pages.isra.105+0xc9/0xc9
    ? kthread_stop+0x110/0x110
    ret_from_fork+0x35/0x40

    Fixes: 1f6a2c6d9f121 ("x86/numa_emulation: Introduce uniform split capability")
    Signed-off-by: Dave Jiang <dave.jiang@intel.com>
    Signed-off-by: Dan Williams <dan.j.williams@intel.com>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Tested-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
    Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: stable@vger.kernel.org
    Link: https://lkml.kernel.org/r/154049911459.2685845.9210186007479774286.stgit@dwillia2-desk3.amr.corp.intel.com

    ---
    arch/x86/mm/numa_emulation.c | 12 ++++++++++--
    1 file changed, 10 insertions(+), 2 deletions(-)

    diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c
    index b54d52a2d00a..d71d72cf6c66 100644
    --- a/arch/x86/mm/numa_emulation.c
    +++ b/arch/x86/mm/numa_emulation.c
    @@ -400,9 +400,17 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
    n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
    ret = -1;
    for_each_node_mask(i, physnode_mask) {
    + /*
    + * The reason we pass in blk[0] is due to
    + * numa_remove_memblk_from() called by
    + * emu_setup_memblk() will delete entry 0
    + * and then move everything else up in the pi.blk
    + * array. Therefore we should always be looking
    + * at blk[0].
    + */
    ret = split_nodes_size_interleave_uniform(&ei, &pi,
    - pi.blk[i].start, pi.blk[i].end, 0,
    - n, &pi.blk[i], nid);
    + pi.blk[0].start, pi.blk[0].end, 0,
    + n, &pi.blk[0], nid);
    if (ret < 0)
    break;
    if (ret < n) {
    \
     
     \ /
      Last update: 2018-10-30 11:41    [W:3.952 / U:1.328 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site