Messages in this thread Patch in this message | | | Date | Mon, 2 Feb 2004 13:29:56 +0000 (GMT) | From | Hugh Dickins <> | Subject | Re: [2.4] heavy-load under swap space shortage |
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On Mon, 2 Feb 2004 j-nomura@ce.jp.nec.com wrote: > > swap_out() seems always trying scan even if there are no swap space available. > This keeps CPU(s) busy with rare successful page-out and may cause lock > contention in big smp system. >... > How about checking nr_swap_pages first and giving up if it's 0?
Sorry, no. Don't be misled by the name, swap_out() is used to free all kinds of mapped pages, not just those which would end up on swap. Your patch just disables freeing mapped pages under memory pressure.
You could try the untested patch below to swap_out_vma(), but I don't really recommend it: it still skips freeing up a less common category of clean pages, just when you'd most like to free them.
Hugh
--- 2.4.25-pre8/mm/vmscan.c 2004-01-30 13:41:14.000000000 +0000 +++ linux/mm/vmscan.c 2004-02-02 13:01:28.067918544 +0000 @@ -263,6 +263,14 @@ if (vma->vm_flags & VM_RESERVED) return count; + /* If no swap, don't waste time on areas which need it */ + if (nr_swap_pages <= 0) { + if (!vma->vm_ops || + !vma->vm_ops->nopage || + vma->vm_ops->nopage == shmem_nopage) + return count; + } + pgdir = pgd_offset(mm, address); end = vma->vm_end; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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