[PATCH] mm: tlb_finish_mmu forget rss

zap_pte_range has been counting the pages it frees in tlb->freed, then
tlb_finish_mmu has used that to update the mm's rss.  That got stranger when I
added anon_rss, yet updated it by a different route; and stranger when rss and
anon_rss became mm_counters with special access macros.  And it would no
longer be viable if we're relying on page_table_lock to stabilize the
mm_counter, but calling tlb_finish_mmu outside that lock.

Remove the mmu_gather's freed field, let tlb_finish_mmu stick to its own
business, just decrement the rss mm_counter in zap_pte_range (yes, there was
some point to batching the update, and a subsequent patch restores that).  And
forget the anal paranoia of first reading the counter to avoid going negative
- if rss does go negative, just fix that bug.

Remove the mmu_gather's flushes and avoided_flushes from arm and arm26: no use
was being made of them.  But arm26 alone was actually using the freed, in the
way some others use need_flush: give it a need_flush.  arm26 seems to prefer
spaces to tabs here: respect that.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 0 insertions, 9 deletions

diff --git a/include/asm-ia64/tlb.h b/include/asm-ia64/tlb.h
index 0bbd79f6a793..834370b9dea1 100644
--- a/include/asm-ia64/tlb.h
+++ b/include/asm-ia64/tlb.h
@@ -60,7 +60,6 @@ struct mmu_gather {
         unsigned int            nr;             /* == ~0U => fast mode */
         unsigned char           fullmm;         /* non-zero means full mm flush */
         unsigned char           need_flush;     /* really unmapped some PTEs? */
-        unsigned long           freed;          /* number of pages freed */
         unsigned long           start_addr;
         unsigned long           end_addr;
         struct page             *pages[FREE_PTE_NR];
@@ -147,7 +146,6 @@ tlb_gather_mmu (struct mm_struct *mm, unsigned int full_mm_flush)
          */
         tlb->nr = (num_online_cpus() == 1) ? ~0U : 0;
         tlb->fullmm = full_mm_flush;
-        tlb->freed = 0;
         tlb->start_addr = ~0UL;
         return tlb;
 }
@@ -159,13 +157,6 @@ tlb_gather_mmu (struct mm_struct *mm, unsigned int full_mm_flush)
 static inline void
 tlb_finish_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end)
 {
-        unsigned long freed = tlb->freed;
-        struct mm_struct *mm = tlb->mm;
-        unsigned long rss = get_mm_counter(mm, rss);
-
-        if (rss < freed)
-                freed = rss;
-        add_mm_counter(mm, rss, -freed);
         /*
          * Note: tlb->nr may be 0 at this point, so we can't rely on tlb->start_addr and
          * tlb->end_addr.