Re: [PATCH] remove no longer use of pdflush interface
From: Fengguang Wu
Date: Mon Jun 04 2012 - 09:34:13 EST
On Mon, Jun 04, 2012 at 09:25:53PM +0800, Wanpeng Li wrote:
> On Mon, Jun 04, 2012 at 08:53:56PM +0800, Fengguang Wu wrote:
> >Hi Wanpeng,
> >
> >On Mon, Jun 04, 2012 at 08:40:42PM +0800, Wanpeng Li wrote:
> >> From: Wanpeng Li <liwp@xxxxxxxxxxxxxxxxxx>
> >>
> >> remove no longer use of pdflush interface nr_pdflush_threads.
> >
> >The patch looks good in itself: the nr_pdflush_threads takes no effect
> >for many of the recent kernels. But what's the normal process of
> >interface removal? Shall we carry some warning printk for some time
> >first or whatever?
>
> Hi, Fengguang,
>
> I also want to add an interface of nr_bdi_writeback_threads to statistic
> how many flusher-x:y currently running, do you think it is a good idea?
Hmm, we try to avoid adding interfaces without a good reason. What
would be the use case? Are there real user demands for this at all?
Thanks,
Fengguang
> >> Signed-off-by: Wanpeng Li <liwp@xxxxxxxxxxxxxxxxxx>
> >> ---
> >> Documentation/sysctl/vm.txt | 11 -----------
> >> fs/fs-writeback.c | 5 -----
> >> include/linux/writeback.h | 5 -----
> >> kernel/sysctl.c | 7 -------
> >> 4 files changed, 28 deletions(-)
> >>
> >> diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
> >> index 96f0ee8..71c17d2 100644
> >> --- a/Documentation/sysctl/vm.txt
> >> +++ b/Documentation/sysctl/vm.txt
> >> @@ -42,7 +42,6 @@ Currently, these files are in /proc/sys/vm:
> >> - mmap_min_addr
> >> - nr_hugepages
> >> - nr_overcommit_hugepages
> >> -- nr_pdflush_threads
> >> - nr_trim_pages (only if CONFIG_MMU=n)
> >> - numa_zonelist_order
> >> - oom_dump_tasks
> >> @@ -426,16 +425,6 @@ See Documentation/vm/hugetlbpage.txt
> >>
> >> ==============================================================
> >>
> >> -nr_pdflush_threads
> >> -
> >> -The current number of pdflush threads. This value is read-only.
> >> -The value changes according to the number of dirty pages in the system.
> >> -
> >> -When necessary, additional pdflush threads are created, one per second, up to
> >> -nr_pdflush_threads_max.
> >> -
> >> -==============================================================
> >> -
> >> nr_trim_pages
> >>
> >> This is available only on NOMMU kernels.
> >> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> >> index 539f36c..30ddb8a 100644
> >> --- a/fs/fs-writeback.c
> >> +++ b/fs/fs-writeback.c
> >> @@ -52,11 +52,6 @@ struct wb_writeback_work {
> >> struct completion *done; /* set if the caller waits */
> >> };
> >>
> >> -/*
> >> - * We don't actually have pdflush, but this one is exported though /proc...
> >> - */
> >> -int nr_pdflush_threads;
> >> -
> >> /**
> >> * writeback_in_progress - determine whether there is writeback in progress
> >> * @bdi: the device's backing_dev_info structure.
> >> diff --git a/include/linux/writeback.h b/include/linux/writeback.h
> >> index a2b84f5..13b5df7 100644
> >> --- a/include/linux/writeback.h
> >> +++ b/include/linux/writeback.h
> >> @@ -193,9 +193,4 @@ void tag_pages_for_writeback(struct address_space *mapping,
> >>
> >> void account_page_redirty(struct page *page);
> >>
> >> -/* pdflush.c */
> >> -extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
> >> - read-only. */
> >> -
> >> -
> >> #endif /* WRITEBACK_H */
> >> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> >> index 4ab1187..e257b61 100644
> >> --- a/kernel/sysctl.c
> >> +++ b/kernel/sysctl.c
> >> @@ -1095,13 +1095,6 @@ static struct ctl_table vm_table[] = {
> >> .extra1 = &zero,
> >> },
> >> {
> >> - .procname = "nr_pdflush_threads",
> >> - .data = &nr_pdflush_threads,
> >> - .maxlen = sizeof nr_pdflush_threads,
> >> - .mode = 0444 /* read-only*/,
> >> - .proc_handler = proc_dointvec,
> >> - },
> >> - {
> >> .procname = "swappiness",
> >> .data = &vm_swappiness,
> >> .maxlen = sizeof(vm_swappiness),
> >> --
> >> 1.7.9.5
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