1 files changed, 68 insertions, 0 deletions

diff --git a/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.17/0157-percpu-x86-don-t-use-PMD_SIZE-as-embedded-atom_size-.patch b/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.17/0157-percpu-x86-don-t-use-PMD_SIZE-as-embedded-atom_size-.patch
new file mode 100644
index 00000000..c948145d
--- /dev/null
+++ b/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.17/0157-percpu-x86-don-t-use-PMD_SIZE-as-embedded-atom_size-.patch
@@ -0,0 +1,68 @@
+From 40bfc308a453997d543e78d6c825275710c48a1c Mon Sep 17 00:00:00 2001
+From: Tejun Heo <tj@kernel.org>
+Date: Fri, 27 Apr 2012 10:54:35 -0700
+Subject: [PATCH 157/165] percpu, x86: don't use PMD_SIZE as embedded
+ atom_size on 32bit
+
+commit d5e28005a1d2e67833852f4c9ea8ec206ea3ff85 upstream.
+
+With the embed percpu first chunk allocator, x86 uses either PAGE_SIZE
+or PMD_SIZE for atom_size.  PMD_SIZE is used when CPU supports PSE so
+that percpu areas are aligned to PMD mappings and possibly allow using
+PMD mappings in vmalloc areas in the future.  Using larger atom_size
+doesn't waste actual memory; however, it does require larger vmalloc
+space allocation later on for !first chunks.
+
+With reasonably sized vmalloc area, PMD_SIZE shouldn't be a problem
+but x86_32 at this point is anything but reasonable in terms of
+address space and using larger atom_size reportedly leads to frequent
+percpu allocation failures on certain setups.
+
+As there is no reason to not use PMD_SIZE on x86_64 as vmalloc space
+is aplenty and most x86_64 configurations support PSE, fix the issue
+by always using PMD_SIZE on x86_64 and PAGE_SIZE on x86_32.
+
+v2: drop cpu_has_pse test and make x86_64 always use PMD_SIZE and
+    x86_32 PAGE_SIZE as suggested by hpa.
+
+Signed-off-by: Tejun Heo <tj@kernel.org>
+Reported-by: Yanmin Zhang <yanmin.zhang@intel.com>
+Reported-by: ShuoX Liu <shuox.liu@intel.com>
+Acked-by: H. Peter Anvin <hpa@zytor.com>
+LKML-Reference: <4F97BA98.6010001@intel.com>
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+---
+ arch/x86/kernel/setup_percpu.c |   14 +++++++++++++-
+ 1 files changed, 13 insertions(+), 1 deletions(-)
+
+diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
+index 71f4727..5a98aa2 100644
+--- a/arch/x86/kernel/setup_percpu.c
++++ b/arch/x86/kernel/setup_percpu.c
+@@ -185,10 +185,22 @@ void __init setup_per_cpu_areas(void)
+ #endif
+        rc = -EINVAL;
+        if (pcpu_chosen_fc != PCPU_FC_PAGE) {
+-               const size_t atom_size = cpu_has_pse ? PMD_SIZE : PAGE_SIZE;
+                const size_t dyn_size = PERCPU_MODULE_RESERVE +
+                        PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
++               size_t atom_size;
+ 
++               /*
++                * On 64bit, use PMD_SIZE for atom_size so that embedded
++                * percpu areas are aligned to PMD.  This, in the future,
++                * can also allow using PMD mappings in vmalloc area.  Use
++                * PAGE_SIZE on 32bit as vmalloc space is highly contended
++                * and large vmalloc area allocs can easily fail.
++                */
++#ifdef CONFIG_X86_64
++               atom_size = PMD_SIZE;
++#else
++               atom_size = PAGE_SIZE;
++#endif
+                rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
+                                            dyn_size, atom_size,
+                                            pcpu_cpu_distance,
+-- 
+1.7.7.6
+