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authorYosry Ahmed <yosryahmed@google.com>2024-02-22 19:09:10 +0000
committerAndrew Morton <akpm@linux-foundation.org>2024-03-04 17:01:14 -0800
commitcd87d9f58439a114f38cec276f3ec1600729c8bf (patch)
treeeae0e93f7270176884af353b1040b62e1def8b36 /arch/x86/mm
parentf5eec03611d9352c8b19134ecd4742a6ebc45282 (diff)
x86/mm: further clarify switch_mm_irqs_off() documentation
Commit accf6b23d1e5a ("x86/mm: clarify "prev" usage in switch_mm_irqs_off()") attempted to clarify x86's usage of the arguments passed by generic code, specifically the "prev" argument the is unused by x86. However, it could have done a better job with the comment above switch_mm_irqs_off(). Rewrite this comment according to Dave Hansen's suggestion. Link: https://lkml.kernel.org/r/20240222190911.1903054-1-yosryahmed@google.com Fixes: 3cfd6625a6cf ("x86/mm: clarify "prev" usage in switch_mm_irqs_off()") Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Suggested-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/tlb.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index bf9605caf24f..b67545baf697 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -493,10 +493,10 @@ static inline void cr4_update_pce_mm(struct mm_struct *mm) { }
#endif
/*
- * The "prev" argument passed by the caller does not always match CR3. For
- * example, the scheduler passes in active_mm when switching from lazy TLB mode
- * to normal mode, but switch_mm_irqs_off() can be called from x86 code without
- * updating active_mm. Use cpu_tlbstate.loaded_mm instead.
+ * This optimizes when not actually switching mm's. Some architectures use the
+ * 'unused' argument for this optimization, but x86 must use
+ * 'cpu_tlbstate.loaded_mm' instead because it does not always keep
+ * 'current->active_mm' up to date.
*/
void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next,
struct task_struct *tsk)