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Message-ID: <CA+CK2bCFWoLL0o2s=WnUyxPaDD09OeuHK5gqkLc6UiGC7r5sRQ@mail.gmail.com>
Date: Tue, 14 May 2024 10:35:40 -0600
From: Pasha Tatashin <pasha.tatashin@...een.com>
To: Suren Baghdasaryan <surenb@...gle.com>
Cc: akpm@...ux-foundation.org, kent.overstreet@...ux.dev, vbabka@...e.cz,
keescook@...omium.org, linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/1] lib: add version into /proc/allocinfo output
On Tue, May 14, 2024 at 10:31 AM Suren Baghdasaryan <surenb@...gle.com> wrote:
>
> Add version string and a header at the beginning of /proc/allocinfo to
> allow later format changes. Example output:
>
> > head /proc/allocinfo
> allocinfo - version: 1.0
> # <size> <calls> <tag info>
> 0 0 init/main.c:1314 func:do_initcalls
> 0 0 init/do_mounts.c:353 func:mount_nodev_root
> 0 0 init/do_mounts.c:187 func:mount_root_generic
> 0 0 init/do_mounts.c:158 func:do_mount_root
> 0 0 init/initramfs.c:493 func:unpack_to_rootfs
> 0 0 init/initramfs.c:492 func:unpack_to_rootfs
> 0 0 init/initramfs.c:491 func:unpack_to_rootfs
> 512 1 arch/x86/events/rapl.c:681 func:init_rapl_pmus
> 128 1 arch/x86/events/rapl.c:571 func:rapl_cpu_online
>
> Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@...een.com>
Thank you,
Pasha
> ---
> Changes since v1 [1]:
> - Added header with field names, per Pasha Tatashin
> - Fixed a spelling error in the changelog
>
> [1] https://lore.kernel.org/all/20240514153532.3622371-1-surenb@google.com/
>
> Documentation/filesystems/proc.rst | 5 ++--
> lib/alloc_tag.c | 48 ++++++++++++++++++++----------
> 2 files changed, 36 insertions(+), 17 deletions(-)
>
> diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
> index 245269dd6e02..4b71b3903d46 100644
> --- a/Documentation/filesystems/proc.rst
> +++ b/Documentation/filesystems/proc.rst
> @@ -961,13 +961,14 @@ Provides information about memory allocations at all locations in the code
> base. Each allocation in the code is identified by its source file, line
> number, module (if originates from a loadable module) and the function calling
> the allocation. The number of bytes allocated and number of calls at each
> -location are reported.
> +location are reported. The first line indicates the version of the file, the
> +second line is the header listing fields in the file.
>
> Example output.
>
> ::
>
> - > sort -rn /proc/allocinfo
> + > tail -n +3 /proc/allocinfo | sort -rn
> 127664128 31168 mm/page_ext.c:270 func:alloc_page_ext
> 56373248 4737 mm/slub.c:2259 func:alloc_slab_page
> 14880768 3633 mm/readahead.c:247 func:page_cache_ra_unbounded
> diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
> index 531dbe2f5456..cbe93939332d 100644
> --- a/lib/alloc_tag.c
> +++ b/lib/alloc_tag.c
> @@ -16,47 +16,61 @@ EXPORT_SYMBOL(_shared_alloc_tag);
> DEFINE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT,
> mem_alloc_profiling_key);
>
> +struct allocinfo_private {
> + struct codetag_iterator iter;
> + bool print_header;
> +
> +};
> +
> static void *allocinfo_start(struct seq_file *m, loff_t *pos)
> {
> - struct codetag_iterator *iter;
> + struct allocinfo_private *priv;
> struct codetag *ct;
> loff_t node = *pos;
>
> - iter = kzalloc(sizeof(*iter), GFP_KERNEL);
> - m->private = iter;
> - if (!iter)
> + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> + m->private = priv;
> + if (!priv)
> return NULL;
>
> + priv->print_header = (node == 0);
> codetag_lock_module_list(alloc_tag_cttype, true);
> - *iter = codetag_get_ct_iter(alloc_tag_cttype);
> - while ((ct = codetag_next_ct(iter)) != NULL && node)
> + priv->iter = codetag_get_ct_iter(alloc_tag_cttype);
> + while ((ct = codetag_next_ct(&priv->iter)) != NULL && node)
> node--;
>
> - return ct ? iter : NULL;
> + return ct ? priv : NULL;
> }
>
> static void *allocinfo_next(struct seq_file *m, void *arg, loff_t *pos)
> {
> - struct codetag_iterator *iter = (struct codetag_iterator *)arg;
> - struct codetag *ct = codetag_next_ct(iter);
> + struct allocinfo_private *priv = (struct allocinfo_private *)arg;
> + struct codetag *ct = codetag_next_ct(&priv->iter);
>
> (*pos)++;
> if (!ct)
> return NULL;
>
> - return iter;
> + return priv;
> }
>
> static void allocinfo_stop(struct seq_file *m, void *arg)
> {
> - struct codetag_iterator *iter = (struct codetag_iterator *)m->private;
> + struct allocinfo_private *priv = (struct allocinfo_private *)m->private;
>
> - if (iter) {
> + if (priv) {
> codetag_lock_module_list(alloc_tag_cttype, false);
> - kfree(iter);
> + kfree(priv);
> }
> }
>
> +static void print_allocinfo_header(struct seq_buf *buf)
> +{
> + /* Output format version, so we can change it. */
> + seq_buf_printf(buf, "allocinfo - version: 1.0\n");
> + seq_buf_printf(buf, "# <size> <calls> <tag info>\n");
> +}
> +
> static void alloc_tag_to_text(struct seq_buf *out, struct codetag *ct)
> {
> struct alloc_tag *tag = ct_to_alloc_tag(ct);
> @@ -71,13 +85,17 @@ static void alloc_tag_to_text(struct seq_buf *out, struct codetag *ct)
>
> static int allocinfo_show(struct seq_file *m, void *arg)
> {
> - struct codetag_iterator *iter = (struct codetag_iterator *)arg;
> + struct allocinfo_private *priv = (struct allocinfo_private *)arg;
> char *bufp;
> size_t n = seq_get_buf(m, &bufp);
> struct seq_buf buf;
>
> seq_buf_init(&buf, bufp, n);
> - alloc_tag_to_text(&buf, iter->ct);
> + if (priv->print_header) {
> + print_allocinfo_header(&buf);
> + priv->print_header = false;
> + }
> + alloc_tag_to_text(&buf, priv->iter.ct);
> seq_commit(m, seq_buf_used(&buf));
> return 0;
> }
>
> base-commit: 7e8aafe0636cdcc5c9699ced05ff1f8ffcb937e2
> --
> 2.45.0.rc1.225.g2a3ae87e7f-goog
>
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