Commit e6b28ec6 authored by Dmitry Safonov's avatar Dmitry Safonov Committed by Thomas Gleixner
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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: default avatarThomas Gleixner <tglx@linutronix.de>
Co-developed-by: default avatarAndrei Vagin <avagin@gmail.com>
Signed-off-by: default avatarAndrei Vagin <avagin@gmail.com>
Signed-off-by: default avatarDmitry Safonov <dima@arista.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-26-dima@arista.com
parent af34ebeb

arch/x86/entry/vdso/vma.c

+16 −1
Original line number Diff line number Diff line
@@ -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) {