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Date: Fri, 28 Nov 2014 11:53:52 +0100
From: Juergen Gross <jgross@...e.com>
To: linux-kernel@...r.kernel.org, xen-devel@...ts.xensource.com,
konrad.wilk@...cle.com, david.vrabel@...rix.com,
boris.ostrovsky@...cle.com, x86@...nel.org, tglx@...utronix.de,
mingo@...hat.com, hpa@...or.com, andrew.cooper3@...rix.com
Cc: Juergen Gross <jgross@...e.com>
Subject: [PATCH V4 03/10] xen: use common page allocation function in p2m.c
In arch/x86/xen/p2m.c three different allocation functions for
obtaining a memory page are used: extend_brk(), alloc_bootmem_align()
or __get_free_page(). Which of those functions is used depends on the
progress of the boot process of the system.
Introduce a common allocation routine selecting the to be called
allocation routine dynamically based on the boot progress. This allows
moving initialization steps without having to care about changing
allocation calls.
Signed-off-by: Juergen Gross <jgross@...e.com>
---
arch/x86/xen/mmu.c | 2 ++
arch/x86/xen/p2m.c | 57 +++++++++++++++++++++++++++++++++---------------------
2 files changed, 37 insertions(+), 22 deletions(-)
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index a8a1a3d..b995b871 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1219,6 +1219,8 @@ static void __init xen_pagetable_init(void)
paging_init();
#ifdef CONFIG_X86_64
xen_pagetable_p2m_copy();
+#else
+ xen_revector_p2m_tree();
#endif
/* Allocate and initialize top and mid mfn levels for p2m structure */
xen_build_mfn_list_list();
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 2d8b908..fa53dc2 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -164,6 +164,7 @@
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/bootmem.h>
+#include <linux/slab.h>
#include <asm/cache.h>
#include <asm/setup.h>
@@ -204,6 +205,8 @@ RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER
*/
RESERVE_BRK(p2m_identity_remap, PAGE_SIZE * 2 * 3 * MAX_REMAP_RANGES);
+static int use_brk = 1;
+
static inline unsigned p2m_top_index(unsigned long pfn)
{
BUG_ON(pfn >= MAX_P2M_PFN);
@@ -268,6 +271,24 @@ static void p2m_init(unsigned long *p2m)
p2m[i] = INVALID_P2M_ENTRY;
}
+static void * __ref alloc_p2m_page(void)
+{
+ if (unlikely(use_brk))
+ return extend_brk(PAGE_SIZE, PAGE_SIZE);
+
+ if (unlikely(!slab_is_available()))
+ return alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);
+
+ return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
+}
+
+/* Only to be called in case of a race for a page just allocated! */
+static void free_p2m_page(void *p)
+{
+ BUG_ON(!slab_is_available());
+ free_page((unsigned long)p);
+}
+
/*
* Build the parallel p2m_top_mfn and p2m_mid_mfn structures
*
@@ -287,13 +308,13 @@ void __ref xen_build_mfn_list_list(void)
/* Pre-initialize p2m_top_mfn to be completely missing */
if (p2m_top_mfn == NULL) {
- p2m_mid_missing_mfn = alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);
+ p2m_mid_missing_mfn = alloc_p2m_page();
p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
- p2m_top_mfn_p = alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);
+ p2m_top_mfn_p = alloc_p2m_page();
p2m_top_mfn_p_init(p2m_top_mfn_p);
- p2m_top_mfn = alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);
+ p2m_top_mfn = alloc_p2m_page();
p2m_top_mfn_init(p2m_top_mfn);
} else {
/* Reinitialise, mfn's all change after migration */
@@ -327,7 +348,7 @@ void __ref xen_build_mfn_list_list(void)
* missing parts of the mfn tree after
* runtime.
*/
- mid_mfn_p = alloc_bootmem_align(PAGE_SIZE, PAGE_SIZE);
+ mid_mfn_p = alloc_p2m_page();
p2m_mid_mfn_init(mid_mfn_p, p2m_missing);
p2m_top_mfn_p[topidx] = mid_mfn_p;
@@ -364,17 +385,17 @@ void __init xen_build_dynamic_phys_to_machine(void)
max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
xen_max_p2m_pfn = max_pfn;
- p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_missing = alloc_p2m_page();
p2m_init(p2m_missing);
- p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_identity = alloc_p2m_page();
p2m_init(p2m_identity);
- p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_mid_missing = alloc_p2m_page();
p2m_mid_init(p2m_mid_missing, p2m_missing);
- p2m_mid_identity = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_mid_identity = alloc_p2m_page();
p2m_mid_init(p2m_mid_identity, p2m_identity);
- p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_top = alloc_p2m_page();
p2m_top_init(p2m_top);
/*
@@ -387,7 +408,7 @@ void __init xen_build_dynamic_phys_to_machine(void)
unsigned mididx = p2m_mid_index(pfn);
if (p2m_top[topidx] == p2m_mid_missing) {
- unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ unsigned long **mid = alloc_p2m_page();
p2m_mid_init(mid, p2m_missing);
p2m_top[topidx] = mid;
@@ -420,6 +441,7 @@ unsigned long __init xen_revector_p2m_tree(void)
unsigned long *mfn_list = NULL;
unsigned long size;
+ use_brk = 0;
va_start = xen_start_info->mfn_list;
/*We copy in increments of P2M_PER_PAGE * sizeof(unsigned long),
* so make sure it is rounded up to that */
@@ -484,6 +506,7 @@ unsigned long __init xen_revector_p2m_tree(void)
#else
unsigned long __init xen_revector_p2m_tree(void)
{
+ use_brk = 0;
return 0;
}
#endif
@@ -510,16 +533,6 @@ unsigned long get_phys_to_machine(unsigned long pfn)
}
EXPORT_SYMBOL_GPL(get_phys_to_machine);
-static void *alloc_p2m_page(void)
-{
- return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
-}
-
-static void free_p2m_page(void *p)
-{
- free_page((unsigned long)p);
-}
-
/*
* Fully allocate the p2m structure for a given pfn. We need to check
* that both the top and mid levels are allocated, and make sure the
@@ -624,7 +637,7 @@ static bool __init early_alloc_p2m(unsigned long pfn, bool check_boundary)
return false;
/* Boundary cross-over for the edges: */
- p2m = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m = alloc_p2m_page();
p2m_init(p2m);
@@ -640,7 +653,7 @@ static bool __init early_alloc_p2m_middle(unsigned long pfn)
mid = p2m_top[topidx];
if (mid == p2m_mid_missing) {
- mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ mid = alloc_p2m_page();
p2m_mid_init(mid, p2m_missing);
--
2.1.2
--
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