remove no longer use of pdflush interface
Subsystems (6)
PATCH v5 1/1 remove no longer use of pdflush interface
From: Wanpeng Li <[email protected]>
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 <[email protected]>
"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
Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads new file +5 -0
@@ -0,0 +1,5 @@ +What: /proc/sys/vm/nr_pdflush_threads +Date: June 2012 +Contact: Wanpeng Li <[email protected]> +Description: Since pdflush is replaced by per-BDI flusher, the interface of old pdflush + exported in /proc/sys/vm/ should be removed.
Documentation/feature-removal-schedule.txt +8 -0
@@ -13,6 +13,14 @@ Who: Jim Cromie <[email protected]>, Jason Baron <[email protected]> --------------------------- +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 <[email protected]> + +--------------------------- + 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,
Documentation/sysctl/vm.txt +0 -11
@@ -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.
fs/fs-writeback.c +0 -5
@@ -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.
include/linux/backing-dev.h +3 -0
@@ -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) {
include/linux/writeback.h +0 -5
@@ -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 */
kernel/sysctl.c +3 -5
@@ -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",
kernel/sysctl_binary.c +1 -1
@@ -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 */
mm/backing-dev.c +20 -0
@@ -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 ; +}
Signature · 1 line
1.7.9.5
mm/backing-dev.c out: · line 904
Quoted 3 lines · Wanpeng Li
mm/backing-dev.c +3
-0+printk_once (KERN_WARNING "%s exported in /proc is scheduled for removal\n" , + table->procname); +
This equals to WARN_ONCE(1, ....);