From e6b28ec65b6d433624a2c290073bc356c4fce914 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Tue, 12 Nov 2019 01:27:14 +0000 Subject: [PATCH] x86/vdso: On timens page fault prefault also VVAR page As timens page has offsets to data on VVAR page VVAR is going to be accessed shortly. Set it up with timens in one page fault as optimization. Suggested-by: Thomas Gleixner Co-developed-by: Andrei Vagin Signed-off-by: Andrei Vagin Signed-off-by: Dmitry Safonov Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20191112012724.250792-26-dima@arista.com --- arch/x86/entry/vdso/vma.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index e5f336112cb1..d2fd8a57af7d 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -170,8 +170,23 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, * offset. * See also the comment near timens_setup_vdso_data(). */ - if (timens_page) + if (timens_page) { + unsigned long addr; + vm_fault_t err; + + /* + * Optimization: inside time namespace pre-fault + * VVAR page too. As on timens page there are only + * offsets for clocks on VVAR, it'll be faulted + * shortly by VDSO code. + */ + addr = vmf->address + (image->sym_timens_page - sym_offset); + err = vmf_insert_pfn(vma, addr, pfn); + if (unlikely(err & VM_FAULT_ERROR)) + return err; + pfn = page_to_pfn(timens_page); + } return vmf_insert_pfn(vma, vmf->address, pfn); } else if (sym_offset == image->sym_pvclock_page) {