Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755561Ab2FERnj (ORCPT ); Tue, 5 Jun 2012 13:43:39 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:50551 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754129Ab2FERnh (ORCPT ); Tue, 5 Jun 2012 13:43:37 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Wanpeng Li Cc: Fengguang Wu , Rob Landley , Alexander Viro , Lucas De Marchi , Andrew Morton , "David S. Miller" , Jan Kara , Mel Gorman , Minchan Kim , David Howells , James Morris , Ingo Molnar , Michel Lespinasse , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Gavin Shan , Wanpeng Li References: <1338888276-3341-1-git-send-email-liwp.linux@gmail.com> Date: Tue, 05 Jun 2012 10:43:02 -0700 In-Reply-To: <1338888276-3341-1-git-send-email-liwp.linux@gmail.com> (Wanpeng Li's message of "Tue, 5 Jun 2012 17:24:36 +0800") Message-ID: <87fwa964ex.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in01.mta.xmission.com;;;ip=98.207.153.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18KjchTDlPAVXjKx7ciAxxrCHhj1UOjMSU= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.0 XMBody_17 BODY: Spammy words in all caps * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0002] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa03 1397; Body=1 Fuz1=1 Fuz2=1] * 0.5 XM_Body_Dirty_Words Contains a dirty word * 0.1 XMSolicitRefs_0 Weightloss drug X-Spam-DCC: XMission; sa03 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Wanpeng Li X-Spam-Relay-Country: Subject: Re: [PATCH] remove no longer use of pdflush interface X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Fri, 06 Aug 2010 16:31:04 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7407 Lines: 199 Wanpeng Li writes: > From: Wanpeng Li > > ------------------ > > Change in v2: > > * add printk warning > * add description in Documentation Do we have old distributions or other users commonly using nr_pdflush_threads? Otherwise we should just remove the tunable as it is a big complicated no-op. If someone is using it we need to do the entire rate limited warning thing. You should at least use printk_ratelimit to keep someone from dosing the system by writing to the file too fast. Eric > ------------------ > > Signed-off-by: Wanpeng Li > --- > .../ABI/obsolete/proc-sys-vm-nr_pdflush_threads | 5 +++++ > Documentation/feature-removal-schedule.txt | 8 ++++++++ > Documentation/sysctl/vm.txt | 11 ----------- > fs/fs-writeback.c | 5 ----- > include/linux/sysctl.h | 3 +++ > include/linux/writeback.h | 5 ----- > kernel/sysctl.c | 18 +++++++++++++----- > kernel/sysctl_binary.c | 2 +- > 8 files changed, 30 insertions(+), 27 deletions(-) > create mode 100644 Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads > > diff --git a/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads b/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads > new file mode 100644 > index 0000000..edbe548 > --- /dev/null > +++ b/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads > @@ -0,0 +1,5 @@ > +What: /proc/sys/vm/nr_pdflush_threads > +Date: June 2012 > +Contact: Wanpeng Li > +Description: Since pdflush is replaced by per-BDI flusher, the interface of old pdflush > + exported in /proc/sys/vm/ should be removed. > diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt > index e4b5775..7eea1ee 100644 > --- a/Documentation/feature-removal-schedule.txt > +++ b/Documentation/feature-removal-schedule.txt > @@ -6,6 +6,14 @@ be removed from this file. > > --------------------------- > > +What: /proc/sys/vm/nr_pdflush_threads > +When: 2012 > +Why: Since pdflush is deprecated, the interface exported in /proc/sys/vm/ > + should be removed. > +Who: Wanpeng Li > + > +--------------------------- > + > What: CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle > When: 2012 > Why: This optional sub-feature of APM is of dubious reliability, > 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/sysctl.h b/include/linux/sysctl.h > index c34b4c8..f25be74 100644 > --- a/include/linux/sysctl.h > +++ b/include/linux/sysctl.h > @@ -964,6 +964,9 @@ extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, > void __user *, size_t *, loff_t *); > extern int proc_do_large_bitmap(struct ctl_table *, int, > void __user *, size_t *, loff_t *); > +extern int proc_deprecated(struct ctl_table *, int, > + void __user *, size_t *, loff_t *); > + > > /* > * Register a set of sysctl names by calling register_sysctl_table > 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..1ab53cb 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -1095,11 +1095,9 @@ 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 = "nr_pdflush_threads", > + .mode = 0444 /* read-only */, > + .proc_handler = proc_deprecated, > }, > { > .procname = "swappiness", > @@ -2505,6 +2503,15 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write, > > #endif /* CONFIG_PROC_SYSCTL */ > > +/* notice associated proc deprecated */ > +int proc_deprecated(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + printk(KERN_WARNING "%s exported in /proc is deprecated\n", > + table->procname); > + return -ENOSYS; > +} > + > /* > * No sense putting this after each symbol definition, twice, > * exception granted :-) > @@ -2517,3 +2524,4 @@ EXPORT_SYMBOL(proc_dointvec_ms_jiffies); > EXPORT_SYMBOL(proc_dostring); > EXPORT_SYMBOL(proc_doulongvec_minmax); > EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax); > +EXPORT_SYMBOL(proc_deprecated); > diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c > index a650694..65bdcf1 100644 > --- a/kernel/sysctl_binary.c > +++ b/kernel/sysctl_binary.c > @@ -147,7 +147,7 @@ static const struct bin_table bin_vm_table[] = { > { CTL_INT, VM_DIRTY_RATIO, "dirty_ratio" }, > /* VM_DIRTY_WB_CS "dirty_writeback_centisecs" no longer used */ > /* VM_DIRTY_EXPIRE_CS "dirty_expire_centisecs" no longer used */ > - { CTL_INT, VM_NR_PDFLUSH_THREADS, "nr_pdflush_threads" }, > + /* VM_NR_PDFLUSH_THREADS "nr_pdflush_threads" no longer used */ > { CTL_INT, VM_OVERCOMMIT_RATIO, "overcommit_ratio" }, > /* VM_PAGEBUF unused */ > /* VM_HUGETLB_PAGES "nr_hugepages" no longer used */ -- 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/