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Tue, 8 Jun 2021 07:35:31 +0000 (UTC) Received: from [192.168.0.105] (unknown [49.204.182.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: faiyazm) by smtp.codeaurora.org (Postfix) with ESMTPSA id E2A16C433D3; Tue, 8 Jun 2021 07:35:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org E2A16C433D3 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=faiyazm@codeaurora.org Subject: Re: [PATCH v11] mm: slub: move sysfs slab alloc/free interfaces to debugfs To: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, vbabka@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, greg@kroah.com, glittao@gmail.com, andy.shevchenko@gmail.com Cc: vinmenon@codeaurora.org References: <1623115958-732-1-git-send-email-faiyazm@codeaurora.org> From: Faiyaz Mohammed Message-ID: Date: Tue, 8 Jun 2021 13:05:23 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <1623115958-732-1-git-send-email-faiyazm@codeaurora.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/8/2021 7:02 AM, Faiyaz Mohammed wrote: > alloc_calls and free_calls implementation in sysfs have two issues, > one is PAGE_SIZE limitation of sysfs and other is it does not adhere > to "one value per file" rule. > > To overcome this issues, move the alloc_calls and free_calls > implementation to debugfs. > > Debugfs cache will be created if SLAB_STORE_USER flag is set. > > Rename the alloc_calls/free_calls to alloc_traces/free_traces, > to be inline with what it does. > > Signed-off-by: Faiyaz Mohammed > --- > changes in v11: > - slab_debug_trace_release updated with seq_release_private. > > changes in v10: > - https://lore.kernel.org/linux-mm/1622996045-25826-1-git-send-email-faiyazm@codeaurora.org/ > > changes in v9: > - https://lore.kernel.org/linux-mm/1622556633-29785-1-git-send-email-faiyazm@codeaurora.org/ > > changes in v8: > - https://lore.kernel.org/linux-mm/1622542057-14632-1-git-send-email-faiyazm@codeaurora.org/ > > changes in V7: > - https://lore.kernel.org/linux-mm/1621928285-751-1-git-send-email-faiyazm@codeaurora.org/ > > changes in v6: > - https://lore.kernel.org/linux-mm/1621341949-26762-1-git-send-email-faiyazm@codeaurora.org/ > > changes in v5: > - https://lore.kernel.org/linux-mm/1620296523-21922-1-git-send-email-faiyazm@codeaurora.org/ > > changes in v4: > - https://lore.kernel.org/linux-mm/1618583239-18124-1-git-send-email-faiyazm@codeaurora.org/ > > changes in v3: > - https://lore.kernel.org/linux-mm/1617712064-12264-1-git-send-email-faiyazm@codeaurora.org/ > > changes in v2: > - https://lore.kernel.org/linux-mm/3ac1d3e6-6207-96ad-16a1-0f5139d8b2b5@codeaurora.org/ > > changes in v1 > - https://lore.kernel.org/linux-mm/1610443287-23933-1-git-send-email-faiyazm@codeaurora.org/ > > mm/slab.h | 6 ++ > mm/slab_common.c | 2 + > mm/slub.c | 282 +++++++++++++++++++++++++++++++++++++------------------ > 3 files changed, 197 insertions(+), 93 deletions(-) > > diff --git a/mm/slab.h b/mm/slab.h > index 18c1927..60d4f4b 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -630,6 +630,12 @@ static inline bool slab_want_init_on_free(struct kmem_cache *c) > return false; > } > > +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG) > +void debugfs_slab_release(struct kmem_cache *); > +#else > +static inline void debugfs_slab_release(struct kmem_cache *s) { } > +#endif > + > #ifdef CONFIG_PRINTK > #define KS_ADDRS_COUNT 16 > struct kmem_obj_info { > diff --git a/mm/slab_common.c b/mm/slab_common.c > index a4a5714..ee5456f 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -449,6 +449,7 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) > rcu_barrier(); > > list_for_each_entry_safe(s, s2, &to_destroy, list) { > + debugfs_slab_release(s); > kfence_shutdown_cache(s); > #ifdef SLAB_SUPPORTS_SYSFS > sysfs_slab_release(s); > @@ -476,6 +477,7 @@ static int shutdown_cache(struct kmem_cache *s) > schedule_work(&slab_caches_to_rcu_destroy_work); > } else { > kfence_shutdown_cache(s); > + debugfs_slab_release(s); > #ifdef SLAB_SUPPORTS_SYSFS > sysfs_slab_unlink(s); > sysfs_slab_release(s); > diff --git a/mm/slub.c b/mm/slub.c > index 3f96e09..09f93ce 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -36,6 +36,7 @@ > #include > #include > > +#include > #include > > #include "internal.h" > @@ -225,6 +226,12 @@ static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p) > { return 0; } > #endif > > +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG) > +static void debugfs_slab_add(struct kmem_cache *); > +#else > +static inline void debugfs_slab_add(struct kmem_cache *s) { } > +#endif > + > static inline void stat(const struct kmem_cache *s, enum stat_item si) > { > #ifdef CONFIG_SLUB_STATS > @@ -4546,6 +4553,9 @@ int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags) > if (err) > __kmem_cache_release(s); > > + if (s->flags & SLAB_STORE_USER) > + debugfs_slab_add(s); > + > return err; > } > > @@ -4686,6 +4696,8 @@ static long validate_slab_cache(struct kmem_cache *s) > > return count; > } > + > +#ifdef CONFIG_DEBUG_FS > /* > * Generate lists of code addresses where slabcache objects are allocated > * and freed. > @@ -4709,6 +4721,8 @@ struct loc_track { > struct location *loc; > }; > > +static struct dentry *slab_debugfs_root; > + > static void free_loc_track(struct loc_track *t) > { > if (t->max) > @@ -4825,82 +4839,7 @@ static void process_slab(struct loc_track *t, struct kmem_cache *s, > add_location(t, s, get_track(s, p, alloc)); > put_map(map); > } > - > -static int list_locations(struct kmem_cache *s, char *buf, > - enum track_item alloc) > -{ > - int len = 0; > - unsigned long i; > - struct loc_track t = { 0, 0, NULL }; > - int node; > - struct kmem_cache_node *n; > - > - if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location), > - GFP_KERNEL)) { > - return sysfs_emit(buf, "Out of memory\n"); > - } > - /* Push back cpu slabs */ > - flush_all(s); > - > - for_each_kmem_cache_node(s, node, n) { > - unsigned long flags; > - struct page *page; > - > - if (!atomic_long_read(&n->nr_slabs)) > - continue; > - > - spin_lock_irqsave(&n->list_lock, flags); > - list_for_each_entry(page, &n->partial, slab_list) > - process_slab(&t, s, page, alloc); > - list_for_each_entry(page, &n->full, slab_list) > - process_slab(&t, s, page, alloc); > - spin_unlock_irqrestore(&n->list_lock, flags); > - } > - > - for (i = 0; i < t.count; i++) { > - struct location *l = &t.loc[i]; > - > - len += sysfs_emit_at(buf, len, "%7ld ", l->count); > - > - if (l->addr) > - len += sysfs_emit_at(buf, len, "%pS", (void *)l->addr); > - else > - len += sysfs_emit_at(buf, len, ""); > - > - if (l->sum_time != l->min_time) > - len += sysfs_emit_at(buf, len, " age=%ld/%ld/%ld", > - l->min_time, > - (long)div_u64(l->sum_time, > - l->count), > - l->max_time); > - else > - len += sysfs_emit_at(buf, len, " age=%ld", l->min_time); > - > - if (l->min_pid != l->max_pid) > - len += sysfs_emit_at(buf, len, " pid=%ld-%ld", > - l->min_pid, l->max_pid); > - else > - len += sysfs_emit_at(buf, len, " pid=%ld", > - l->min_pid); > - > - if (num_online_cpus() > 1 && > - !cpumask_empty(to_cpumask(l->cpus))) > - len += sysfs_emit_at(buf, len, " cpus=%*pbl", > - cpumask_pr_args(to_cpumask(l->cpus))); > - > - if (nr_online_nodes > 1 && !nodes_empty(l->nodes)) > - len += sysfs_emit_at(buf, len, " nodes=%*pbl", > - nodemask_pr_args(&l->nodes)); > - > - len += sysfs_emit_at(buf, len, "\n"); > - } > - > - free_loc_track(&t); > - if (!t.count) > - len += sysfs_emit_at(buf, len, "No data\n"); > - > - return len; > -} > +#endif /* CONFIG_DEBUG_FS */ > #endif /* CONFIG_SLUB_DEBUG */ > > #ifdef SLUB_RESILIENCY_TEST > @@ -5350,21 +5289,6 @@ static ssize_t validate_store(struct kmem_cache *s, > } > SLAB_ATTR(validate); > > -static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf) > -{ > - if (!(s->flags & SLAB_STORE_USER)) > - return -ENOSYS; > - return list_locations(s, buf, TRACK_ALLOC); > -} > -SLAB_ATTR_RO(alloc_calls); > - > -static ssize_t free_calls_show(struct kmem_cache *s, char *buf) > -{ > - if (!(s->flags & SLAB_STORE_USER)) > - return -ENOSYS; > - return list_locations(s, buf, TRACK_FREE); > -} > -SLAB_ATTR_RO(free_calls); > #endif /* CONFIG_SLUB_DEBUG */ > > #ifdef CONFIG_FAILSLAB > @@ -5528,8 +5452,6 @@ static struct attribute *slab_attrs[] = { > &poison_attr.attr, > &store_user_attr.attr, > &validate_attr.attr, > - &alloc_calls_attr.attr, > - &free_calls_attr.attr, > #endif > #ifdef CONFIG_ZONE_DMA > &cache_dma_attr.attr, > @@ -5818,6 +5740,180 @@ static int __init slab_sysfs_init(void) > __initcall(slab_sysfs_init); > #endif /* CONFIG_SYSFS */ > > +#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS) > +static int slab_debugfs_show(struct seq_file *seq, void *v) > +{ > + > + struct location *l; > + unsigned int idx = *(unsigned int *)v; > + struct loc_track *t = seq->private; > + > + if (idx < t->count) { > + l = &t->loc[idx]; > + > + seq_printf(seq, "%7ld ", l->count); > + > + if (l->addr) > + seq_printf(seq, "%pS", (void *)l->addr); > + else > + seq_puts(seq, ""); > + > + if (l->sum_time != l->min_time) { > + seq_printf(seq, " age=%ld/%llu/%ld", > + l->min_time, div_u64(l->sum_time, l->count), > + l->max_time); > + } else > + seq_printf(seq, " age=%ld", l->min_time); > + > + if (l->min_pid != l->max_pid) > + seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid); > + else > + seq_printf(seq, " pid=%ld", > + l->min_pid); > + > + if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus))) > + seq_printf(seq, " cpus=%*pbl", > + cpumask_pr_args(to_cpumask(l->cpus))); > + > + if (nr_online_nodes > 1 && !nodes_empty(l->nodes)) > + seq_printf(seq, " nodes=%*pbl", > + nodemask_pr_args(&l->nodes)); > + > + seq_puts(seq, "\n"); > + } > + > + if (!idx && !t->count) > + seq_puts(seq, "No data\n"); > + > + return 0; > +} > + > +static void slab_debugfs_stop(struct seq_file *seq, void *v) > +{ > + kfree(v); > +} > + > +static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos) > +{ > + loff_t *spos = v; > + struct loc_track *t = seq->private; > + > + if (*ppos < t->count) { > + *ppos = ++*spos; > + return spos; > + } > + *ppos = ++*spos; > + return NULL; > +} > + > +static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos) > +{ > + loff_t *spos = kmalloc(sizeof(loff_t), GFP_KERNEL); > + > + if (!spos) > + return NULL; > + > + *spos = *ppos; > + return spos; > +} > + > +static const struct seq_operations slab_debugfs_sops = { > + .start = slab_debugfs_start, > + .next = slab_debugfs_next, > + .stop = slab_debugfs_stop, > + .show = slab_debugfs_show, > +}; > + > +static int slab_debug_trace_open(struct inode *inode, struct file *filep) > +{ > + > + struct kmem_cache_node *n; > + enum track_item alloc; > + int node; > + struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops, > + sizeof(struct loc_track)); > + struct kmem_cache *s = file_inode(filep)->i_private; > + > + if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0) > + alloc = TRACK_ALLOC; > + else > + alloc = TRACK_FREE; > + > + if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) > + return -ENOMEM; > + > + /* Push back cpu slabs */ > + flush_all(s); > + > + for_each_kmem_cache_node(s, node, n) { > + unsigned long flags; > + struct page *page; > + > + if (!atomic_long_read(&n->nr_slabs)) > + continue; > + > + spin_lock_irqsave(&n->list_lock, flags); > + list_for_each_entry(page, &n->partial, slab_list) > + process_slab(t, s, page, alloc); > + list_for_each_entry(page, &n->full, slab_list) > + process_slab(t, s, page, alloc); > + spin_unlock_irqrestore(&n->list_lock, flags); > + } > + > + return 0; > +} > + > +static int slab_debug_trace_release(struct inode *inode, struct file *file) > +{ Please ignore this patch, while doing clean up I missed the "struct seq_file *seq = file->private_data;" I will push the patch with same patch version. > + struct loc_track *t = seq->private;> + > + free_loc_track(t); > + return seq_release_private(inode, file); > +} > + > +static const struct file_operations slab_debugfs_fops = { > + .open = slab_debug_trace_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = slab_debug_trace_release, > +}; > + > +static void debugfs_slab_add(struct kmem_cache *s) > +{ > + struct dentry *slab_cache_dir; > + > + if (unlikely(!slab_debugfs_root)) > + return; > + > + slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root); > + > + debugfs_create_file("alloc_traces", 0400, > + slab_cache_dir, s, &slab_debugfs_fops); > + > + debugfs_create_file("free_traces", 0400, > + slab_cache_dir, s, &slab_debugfs_fops); > +} > + > +void debugfs_slab_release(struct kmem_cache *s) > +{ > + debugfs_remove_recursive(debugfs_lookup(s->name, slab_debugfs_root)); > +} > + > +static int __init slab_debugfs_init(void) > +{ > + struct kmem_cache *s; > + > + slab_debugfs_root = debugfs_create_dir("slab", NULL); > + > + list_for_each_entry(s, &slab_caches, list) > + if (s->flags & SLAB_STORE_USER) > + debugfs_slab_add(s); > + > + return 0; > + > +} > +__initcall(slab_debugfs_init); > +#endif > /* > * The /proc/slabinfo ABI > */ > Thanks and regards, Mohammed Faiyaz