| Message ID | 1500298773-7510-3-git-send-email-longman@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jul 17, 2017 at 09:39:31AM -0400, Waiman Long wrote: > @@ -63,9 +63,10 @@ struct qstr { > struct dentry_stat_t { > long nr_dentry; > long nr_unused; > - long age_limit; /* age in seconds */ > - long want_pages; /* pages requested by system */ > - long dummy[2]; > + long nr_negative; /* # of negative dentries */ > + long age_limit; /* age in seconds */ > + long want_pages; /* pages requested by system */ > + long dummy; > }; > extern struct dentry_stat_t dentry_stat; You can't just insert a field in the middle like that. It'll break any code parsing /proc/sys/fs/dentry-state. You have to put it at the end: long age_limit; /* age in seconds */ long want_pages; /* pages requested by system */ - long dummy[2]; + long nr_negative; /* # of negative dentries */ + long dummy; };
On 07/17/2017 10:09 AM, Matthew Wilcox wrote: > On Mon, Jul 17, 2017 at 09:39:31AM -0400, Waiman Long wrote: >> @@ -63,9 +63,10 @@ struct qstr { >> struct dentry_stat_t { >> long nr_dentry; >> long nr_unused; >> - long age_limit; /* age in seconds */ >> - long want_pages; /* pages requested by system */ >> - long dummy[2]; >> + long nr_negative; /* # of negative dentries */ >> + long age_limit; /* age in seconds */ >> + long want_pages; /* pages requested by system */ >> + long dummy; >> }; >> extern struct dentry_stat_t dentry_stat; > You can't just insert a field in the middle like that. It'll break any code > parsing /proc/sys/fs/dentry-state. You have to put it at the end: > > long age_limit; /* age in seconds */ > long want_pages; /* pages requested by system */ > - long dummy[2]; > + long nr_negative; /* # of negative dentries */ > + long dummy; > }; My mistake. I will send out an updated patches later on after collecting more feedback to make the new field go to the end. Cheers, Longman
diff --git a/fs/dcache.c b/fs/dcache.c index 6a0a844..bb0a519 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -135,6 +135,7 @@ struct dentry_stat_t dentry_stat = { */ #define NEG_DENTRY_BATCH (1 << 8) static long neg_dentry_percpu_limit __read_mostly; +static long neg_dentry_nfree_init __read_mostly; /* Free pool initial value */ static struct { raw_spinlock_t nfree_lock; long nfree; /* Negative dentry free pool */ @@ -176,11 +177,23 @@ static long get_nr_dentry_unused(void) return sum < 0 ? 0 : sum; } +static long get_nr_dentry_neg(void) +{ + int i; + long sum = 0; + + for_each_possible_cpu(i) + sum += per_cpu(nr_dentry_neg, i); + sum += neg_dentry_nfree_init - ndblk.nfree; + return sum < 0 ? 0 : sum; +} + int proc_nr_dentry(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { dentry_stat.nr_dentry = get_nr_dentry(); dentry_stat.nr_unused = get_nr_dentry_unused(); + dentry_stat.nr_negative = get_nr_dentry_neg(); return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); } #endif @@ -3704,7 +3717,8 @@ static void __init neg_dentry_init(void) raw_spin_lock_init(&ndblk.nfree_lock); /* 20% in global pool & 80% in percpu free */ - ndblk.nfree = totalram_pages * nr_dentry_page * neg_dentry_pc / 500; + ndblk.nfree = neg_dentry_nfree_init + = totalram_pages * nr_dentry_page * neg_dentry_pc / 500; cnt = ndblk.nfree * 4 / num_possible_cpus(); if (unlikely(cnt < 2 * NEG_DENTRY_BATCH)) cnt = 2 * NEG_DENTRY_BATCH; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 498233b..184669f 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -63,9 +63,10 @@ struct qstr { struct dentry_stat_t { long nr_dentry; long nr_unused; - long age_limit; /* age in seconds */ - long want_pages; /* pages requested by system */ - long dummy[2]; + long nr_negative; /* # of negative dentries */ + long age_limit; /* age in seconds */ + long want_pages; /* pages requested by system */ + long dummy; }; extern struct dentry_stat_t dentry_stat;
The number of negative dentries currently in the system is now reported in the /proc/sys/fs/dentry-state file. Signed-off-by: Waiman Long <longman@redhat.com> --- fs/dcache.c | 16 +++++++++++++++- include/linux/dcache.h | 7 ++++--- 2 files changed, 19 insertions(+), 4 deletions(-)