* [PATCH v5] remove no longer use of pdflush interface
@ 2012-06-11 0:29 Wanpeng Li
0 siblings, 0 replies; 3+ messages in thread
From: Wanpeng Li @ 2012-06-11 0:29 UTC (permalink / raw)
To: Andrew Morton
Cc: Wu Fengguang, Rob Landley, Alexander Viro, Jan Kara,
Curt Wohlgemuth, Mike Frysinger, Michal Hocko, Johannes Weiner,
Eric W. Biederman, David Howells, James Morris, Ingo Molnar,
David S. Miller, Vasily Averin, Michel Lespinasse, Jens Axboe,
Rabin Vincent, linux-doc, linux-kernel, linux-fsdevel, linux-mm,
Gavin Shan, Wanpeng Li, Wanpeng Li
From: Wanpeng Li <liwp@linux.vnet.ibm.com>
Since per-BDI flusher introduced to linux 2.6, pdflush mechanism is not
used any more, but the old interface of pdflush exported through /proc/sys/vm/
is still existing and obviously useless. In order for back-compatibility,
printk warning information and return 0 to notify the users that the
interface is removed.
Signed-off-by: Wanpeng Li <liwp@linux.vnet.ibm.com>
"V4 -> V5":
* remove useless comment
* copy "0\n" out to userspace and return 2
"V3 -> V4":
* replace generic proc_obsolete() by pdflush_proc_obsolete() which just
addresses old pdflush interface
"V2 -> V3":
* rename proc_deprecated() to proc_obsolete()
* replace printk in proc_obsolete by prink_once and change warning
* information
"V1 -> V2":
* add printk warning
* add description in Documentation
---
.../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/backing-dev.h | 3 +++
include/linux/writeback.h | 5 -----
kernel/sysctl.c | 8 +++-----
kernel/sysctl_binary.c | 2 +-
mm/backing-dev.c | 20 ++++++++++++++++++++
9 files changed, 40 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..b0b0eeb
--- /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 <liwp@linux.vnet.ibm.com>
+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 56000b3..8e4a60c 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -13,6 +13,14 @@ Who: Jim Cromie <jim.cromie@gmail.com>, Jason Baron <jbaron@redhat.com>
---------------------------
+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 <liwp@linux.vnet.ibm.com>
+
+---------------------------
+
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 d462fe7..37e9ced 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/backing-dev.h b/include/linux/backing-dev.h
index b1038bd..db7a5ab 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -17,6 +17,7 @@
#include <linux/timer.h>
#include <linux/writeback.h>
#include <linux/atomic.h>
+#include <linux/sysctl.h>
struct page;
struct device;
@@ -304,6 +305,8 @@ void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
void set_bdi_congested(struct backing_dev_info *bdi, int sync);
long congestion_wait(int sync, long timeout);
long wait_iff_congested(struct zone *zone, int sync, long timeout);
+int pdflush_proc_obsolete(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
{
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 6d0a0fc..c66fe33 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -189,9 +189,4 @@ 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..b3b9ba4 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 = pdflush_proc_obsolete,
},
{
.procname = "swappiness",
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 */
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index dd8e2aa..e9caa10 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -886,3 +886,23 @@ out:
return ret;
}
EXPORT_SYMBOL(wait_iff_congested);
+
+int pdflush_proc_obsolete(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ char kbuf[] = "0\n";
+
+ if (*ppos) {
+ *lenp = 0;
+ return 0;
+ }
+
+ if (copy_to_user(buffer, kbuf, sizeof(kbuf)))
+ return -EFAULT;
+ printk_once(KERN_WARNING "%s exported in /proc is scheduled for removal\n",
+ table->procname);
+
+ *lenp = 2;
+ *ppos += *lenp;
+ return 0;
+}
--
1.7.9.5
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH v5] remove no longer use of pdflush interface
@ 2012-06-11 0:31 Wanpeng Li
2012-06-13 6:18 ` Cong Wang
0 siblings, 1 reply; 3+ messages in thread
From: Wanpeng Li @ 2012-06-11 0:31 UTC (permalink / raw)
To: Andrew Morton
Cc: Wu Fengguang, Rob Landley, Alexander Viro, Jan Kara,
Curt Wohlgemuth, Mike Frysinger, Michal Hocko, Johannes Weiner,
Eric W. Biederman, David Howells, James Morris, Ingo Molnar,
David S. Miller, Vasily Averin, Michel Lespinasse, Jens Axboe,
Rabin Vincent, linux-doc, linux-kernel, linux-fsdevel, linux-mm,
Gavin Shan, Wanpeng Li, Wanpeng Li
From: Wanpeng Li <liwp@linux.vnet.ibm.com>
Since per-BDI flusher introduced to linux 2.6, pdflush mechanism is not
used any more, but the old interface of pdflush exported through /proc/sys/vm/
is still existing and obviously useless. In order for back-compatibility,
printk warning information and return 2 to notify the users that the
interface is removed.
Signed-off-by: Wanpeng Li <liwp@linux.vnet.ibm.com>
"V4 -> V5":
* remove useless comment
* copy "0\n" out to userspace and return 2
"V3 -> V4":
* replace generic proc_obsolete() by pdflush_proc_obsolete() which just
addresses old pdflush interface
"V2 -> V3":
* rename proc_deprecated() to proc_obsolete()
* replace printk in proc_obsolete by prink_once and change warning
* information
"V1 -> V2":
* add printk warning
* add description in Documentation
---
.../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/backing-dev.h | 3 +++
include/linux/writeback.h | 5 -----
kernel/sysctl.c | 8 +++-----
kernel/sysctl_binary.c | 2 +-
mm/backing-dev.c | 20 ++++++++++++++++++++
9 files changed, 40 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..b0b0eeb
--- /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 <liwp@linux.vnet.ibm.com>
+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 56000b3..8e4a60c 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -13,6 +13,14 @@ Who: Jim Cromie <jim.cromie@gmail.com>, Jason Baron <jbaron@redhat.com>
---------------------------
+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 <liwp@linux.vnet.ibm.com>
+
+---------------------------
+
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 d462fe7..37e9ced 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/backing-dev.h b/include/linux/backing-dev.h
index b1038bd..db7a5ab 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -17,6 +17,7 @@
#include <linux/timer.h>
#include <linux/writeback.h>
#include <linux/atomic.h>
+#include <linux/sysctl.h>
struct page;
struct device;
@@ -304,6 +305,8 @@ void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
void set_bdi_congested(struct backing_dev_info *bdi, int sync);
long congestion_wait(int sync, long timeout);
long wait_iff_congested(struct zone *zone, int sync, long timeout);
+int pdflush_proc_obsolete(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
{
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 6d0a0fc..c66fe33 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -189,9 +189,4 @@ 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..b3b9ba4 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 = pdflush_proc_obsolete,
},
{
.procname = "swappiness",
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 */
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index dd8e2aa..e9caa10 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -886,3 +886,23 @@ out:
return ret;
}
EXPORT_SYMBOL(wait_iff_congested);
+
+int pdflush_proc_obsolete(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ char kbuf[] = "0\n";
+
+ if (*ppos) {
+ *lenp = 0;
+ return 0;
+ }
+
+ if (copy_to_user(buffer, kbuf, sizeof(kbuf)))
+ return -EFAULT;
+ printk_once(KERN_WARNING "%s exported in /proc is scheduled for removal\n",
+ table->procname);
+
+ *lenp = 2;
+ *ppos += *lenp;
+ return 2;
+}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v5] remove no longer use of pdflush interface
2012-06-11 0:31 [PATCH v5] remove no longer use of pdflush interface Wanpeng Li
@ 2012-06-13 6:18 ` Cong Wang
0 siblings, 0 replies; 3+ messages in thread
From: Cong Wang @ 2012-06-13 6:18 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-doc, linux-kernel, linux-mm
On Mon, 11 Jun 2012 at 00:31 GMT, Wanpeng Li <liwp.linux@gmail.com> wrote:
> + printk_once(KERN_WARNING "%s exported in /proc is scheduled for removal\n",
> + table->procname);
> +
This equals to WARN_ONCE(1, ....);
^ permalink raw reply [flat|nested] 3+ messages in thread
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