[PATCH 11/15] xen/mmu: tune pgtable alloc/release

Jeremy Fitzhardinge
2011-06-20T22:16:54Z

Make sure the fastpath code is inlined. Batch the page permission change
and the pin/unpin, and make sure that it can be batched with any
adjacent set_pte/pmd/etc operations.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
arch/x86/xen/mmu.c | 49 ++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 112259f..ebfdc3d 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1492,22 +1492,52 @@ static void __init xen_release_pmd_init(unsigned long pfn)
make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
}

+static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+ struct multicall_space mcs;
+ struct mmuext_op *op;
+
+ mcs = __xen_mc_entry(sizeof(*op));
+ op = mcs.args;
+ op->cmd = cmd;
+ op->arg1.mfn = pfn_to_mfn(pfn);
+
+ MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+}
+
+static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
+{
+ struct multicall_space mcs;
+ unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
+
+ mcs = __xen_mc_entry(0);
+ MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
+ pfn_pte(pfn, prot), 0);
+}
+
/* This needs to make sure the new pte page is pinned iff its being
attached to a pinned pagetable. */
-static void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn, unsigned level)
+static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
+ unsigned level)
{
- struct page *page = pfn_to_page(pfn);
int pinned = PagePinned(virt_to_page(mm->pgd));

trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);

if (pinned) {
+ struct page *page = pfn_to_page(pfn);
+
SetPagePinned(page);

if (!PageHighMem(page)) {
- make_lowmem_page_readonly(__va(PFN_PHYS((unsigned long)pfn)));
+ xen_mc_batch();
+
+ __set_pfn_prot(pfn, PAGE_KERNEL_RO);
+
if (level == PT_PTE && USE_SPLIT_PTLOCKS)
- pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+ __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
} else {
/* make sure there are no stray mappings of
this page */
@@ -1527,7 +1557,7 @@ static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
}

/* This should never happen until we're OK to use struct page */
-static void xen_release_ptpage(unsigned long pfn, unsigned level)
+static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
{
struct page *page = pfn_to_page(pfn);
bool pinned = PagePinned(page);
@@ -1536,9 +1566,14 @@ static void xen_release_ptpage(unsigned long pfn, unsigned level)

if (pinned) {
if (!PageHighMem(page)) {
+ xen_mc_batch();
+
if (level == PT_PTE && USE_SPLIT_PTLOCKS)
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
- make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+ __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+
+ __set_pfn_prot(pfn, PAGE_KERNEL);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
}
ClearPagePinned(page);
}
--
1.7.5.4