Messages in this thread Patch in this message | | | From | Ingo Molnar <> | Subject | [PATCH 06/11] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code | Date | Tue, 22 Sep 2015 08:23:36 +0200 |
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xen_mm_pin_all()/unpin_all() are used to implement full guest instance suspend/restore. It's a stop-all method that needs to iterate through all allocated pgds in the system to fix them up for Xen's use.
This code uses pgd_list, probably because it was an easy interface.
But we want to remove the pgd_list, so convert the code over to walk all tasks in the system. This is an equivalent method.
(As I don't use Xen this is was only build tested.)
Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <Waiman.Long@hp.com> Cc: linux-mm@kvack.org Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/xen/mmu.c | 45 +++++++++++++++++++++++++++++++++++++++------ 1 file changed, 39 insertions(+), 6 deletions(-)
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 9c479fe40459..96bb4a7a626d 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -45,6 +45,7 @@ #include <linux/vmalloc.h> #include <linux/module.h> #include <linux/gfp.h> +#include <linux/oom.h> #include <linux/memblock.h> #include <linux/seq_file.h> #include <linux/crash_dump.h> @@ -854,18 +855,34 @@ static void xen_pgd_pin(struct mm_struct *mm) */ void xen_mm_pin_all(void) { - struct page *page; + struct task_struct *g; + rcu_read_lock(); /* Task list walk */ spin_lock(&pgd_lock); - list_for_each_entry(page, &pgd_list, lru) { + for_each_process(g) { + struct task_struct *p; + struct mm_struct *mm; + struct page *page; + pgd_t *pgd; + + p = find_lock_task_mm(g); + if (!p) + continue; + + mm = p->mm; + pgd = mm->pgd; + page = virt_to_page(pgd); + if (!PagePinned(page)) { - __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page)); + __xen_pgd_pin(&init_mm, pgd); SetPageSavePinned(page); } + task_unlock(p); } spin_unlock(&pgd_lock); + rcu_read_unlock(); } /* @@ -968,19 +985,35 @@ static void xen_pgd_unpin(struct mm_struct *mm) */ void xen_mm_unpin_all(void) { - struct page *page; + struct task_struct *g; + rcu_read_lock(); /* Task list walk */ spin_lock(&pgd_lock); - list_for_each_entry(page, &pgd_list, lru) { + for_each_process(g) { + struct task_struct *p; + struct mm_struct *mm; + struct page *page; + pgd_t *pgd; + + p = find_lock_task_mm(g); + if (!p) + continue; + + mm = p->mm; + pgd = mm->pgd; + page = virt_to_page(pgd); + if (PageSavePinned(page)) { BUG_ON(!PagePinned(page)); - __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page)); + __xen_pgd_unpin(&init_mm, pgd); ClearPageSavePinned(page); } + task_unlock(p); } spin_unlock(&pgd_lock); + rcu_read_unlock(); } static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next) -- 2.1.4
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