linux-kernel - Re: mmotm 2011-04-29 - wonky VmRSS and VmHWM values after swapping

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Date:	Mon, 02 May 2011 19:57:32 -0400
From:	Valdis.Kletnieks@...edu
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: mmotm 2011-04-29 - wonky VmRSS and VmHWM values after swapping

On Mon, 02 May 2011 16:44:30 PDT, Andrew Morton said:

> hm, me too.  After boot, hald has a get_mm_counter(mm, MM_ANONPAGES) of
> 0xffffffffffff3c27.  Bisected to Pater's
> mm-extended-batches-for-generic-mmu_gather.patch, can't see how it did
> that.

Looking at it:
@@ -177,15 +205,24 @@ tlb_finish_mmu(struct mmu_gather *tlb, u
  */
 static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
 {
+       struct mmu_gather_batch *batch;
+
        tlb->need_flush = 1;
+
        if (tlb_fast_mode(tlb)) {
                free_page_and_swap_cache(page);
                return 1; /* avoid calling tlb_flush_mmu() */
        }
-       tlb->pages[tlb->nr++] = page;
-       VM_BUG_ON(tlb->nr > tlb->max);

-       return tlb->max - tlb->nr;
+       batch = tlb->active;
+       batch->pages[batch->nr++] = page;
+       VM_BUG_ON(batch->nr > batch->max);
+       if (batch->nr == batch->max) {
+               if (!tlb_next_batch(tlb))
+                       return 0;
+       }
+
+       return batch->max - batch->nr;
 }

Who's intializing/setting batch->max?  Perhaps whoever set up tlb->active
failed to do so?



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