The patch titled writeback: report dirty thresholds in /proc/vmstat has been added to the -mm tree. Its filename is writeback-report-dirty-thresholds-in-proc-vmstat.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: writeback: report dirty thresholds in /proc/vmstat From: Michael Rubin <mrubin@xxxxxxxxxx> The kernel already exposes the user desired thresholds in /proc/sys/vm with dirty_background_ratio and background_ratio. But the kernel may alter the number requested without giving the user any indication that is the case. Knowing the actual ratios the kernel is honoring can help app developers understand how their buffered IO will be sent to the disk. $ grep threshold /proc/vmstat nr_dirty_threshold 409111 nr_dirty_background_threshold 818223 Signed-off-by: Michael Rubin <mrubin@xxxxxxxxxx> Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmstat.c | 39 +++++++++++++++++++++++++-------------- 1 file changed, 25 insertions(+), 14 deletions(-) diff -puN mm/vmstat.c~writeback-report-dirty-thresholds-in-proc-vmstat mm/vmstat.c --- a/mm/vmstat.c~writeback-report-dirty-thresholds-in-proc-vmstat +++ a/mm/vmstat.c @@ -17,6 +17,7 @@ #include <linux/vmstat.h> #include <linux/sched.h> #include <linux/math64.h> +#include <linux/writeback.h> #ifdef CONFIG_VM_EVENT_COUNTERS DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}}; @@ -747,6 +748,8 @@ static const char * const vmstat_text[] "nr_shmem", "nr_dirtied", "nr_written", + "nr_dirty_threshold", + "nr_dirty_background_threshold", #ifdef CONFIG_NUMA "numa_hit", @@ -907,36 +910,44 @@ static const struct file_operations proc .release = seq_release, }; +enum writeback_stat_item { + NR_DIRTY_THRESHOLD, + NR_DIRTY_BG_THRESHOLD, + NR_VM_WRITEBACK_STAT_ITEMS, +}; + static void *vmstat_start(struct seq_file *m, loff_t *pos) { unsigned long *v; -#ifdef CONFIG_VM_EVENT_COUNTERS - unsigned long *e; -#endif - int i; + int i, stat_items_size; if (*pos >= ARRAY_SIZE(vmstat_text)) return NULL; + stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) + + NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long); #ifdef CONFIG_VM_EVENT_COUNTERS - v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) - + sizeof(struct vm_event_state), GFP_KERNEL); -#else - v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long), - GFP_KERNEL); + stat_items_size += sizeof(struct vm_event_state); #endif + + v = kmalloc(stat_items_size, GFP_KERNEL); m->private = v; if (!v) return ERR_PTR(-ENOMEM); for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) v[i] = global_page_state(i); + v += NR_VM_ZONE_STAT_ITEMS; + + global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD, + v + NR_DIRTY_THRESHOLD); + v += NR_VM_WRITEBACK_STAT_ITEMS; + #ifdef CONFIG_VM_EVENT_COUNTERS - e = v + NR_VM_ZONE_STAT_ITEMS; - all_vm_events(e); - e[PGPGIN] /= 2; /* sectors -> kbytes */ - e[PGPGOUT] /= 2; + all_vm_events(v); + v[PGPGIN] /= 2; /* sectors -> kbytes */ + v[PGPGOUT] /= 2; #endif - return v + *pos; + return m->private + *pos; } static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos) _ Patches currently in -mm which might be from mrubin@xxxxxxxxxx are vmscan-do-not-writeback-filesystem-pages-in-direct-reclaim.patch vmscan-kick-flusher-threads-to-clean-pages-when-reclaim-is-encountering-dirty-pages.patch mm-export-account_page_dirty.patch mm-add-account_page_writeback.patch writeback-add-nr_dirtied-and-nr_written-to-proc-vmstat.patch writeback-add-nr_dirtied-and-nr_written-to-proc-vmstat-fix.patch writeback-add-sys-devices-system-node-node-vmstat.patch writeback-report-dirty-thresholds-in-proc-vmstat.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html