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Date: Wed, 27 Feb 2013 11:46:06 -0700
From: David Ahern <dsahern@...il.com>
To: chenggang <chenggang.qin@...il.com>
CC: linux-kernel@...r.kernel.org, chenggang <chenggang.qcg@...bao.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Paul Mackerras <paulus@...ba.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
Arjan van de Ven <arjan@...ux.intel.com>,
Namhyung Kim <namhyung@...il.com>,
Yanmin Zhang <yanmin.zhang@...el.com>,
Wu Fengguang <fengguang.wu@...el.com>,
Mike Galbraith <efault@....de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2 1/4] Transform xyarray to linked list
On 2/26/13 2:20 AM, chenggang wrote:
> From: chenggang <chenggang.qcg@...bao.com>
>
> The 2-dimensional array cannot expand and shrink easily while we want to
> response the thread's fork and exit events on-the-fly.
perhaps a better explanation of why -- file descriptors for perf events
are kept in an xyarray where the x dimension is cpus and the y dimension
is threads of interest. You want to be able to grow and shrink the y
dimension as monitored processes spawn and terminate threads.
> We transform xyarray to a 2-demesional linked list. The row is still a array,
> but column is implemented as a list. The number of nodes in every row are same.
> The interface to append and shrink a exist xyarray is provided.
> 1) xyarray__append()
> append a column for all rows.
> 2) xyarray__remove()
> remove a column for all rows.
>
> Cc: David Ahern <dsahern@...il.com>
> Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
> Cc: Paul Mackerras <paulus@...ba.org>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
> Cc: Arjan van de Ven <arjan@...ux.intel.com>
> Cc: Namhyung Kim <namhyung@...il.com>
> Cc: Yanmin Zhang <yanmin.zhang@...el.com>
> Cc: Wu Fengguang <fengguang.wu@...el.com>
> Cc: Mike Galbraith <efault@....de>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Signed-off-by: Chenggang Qin <chenggang.qcg@...bao.com>
>
> ---
> tools/perf/util/xyarray.c | 85 +++++++++++++++++++++++++++++++++++++++++----
> tools/perf/util/xyarray.h | 25 +++++++++++--
> 2 files changed, 101 insertions(+), 9 deletions(-)
>
> diff --git a/tools/perf/util/xyarray.c b/tools/perf/util/xyarray.c
> index 22afbf6..fc48bda 100644
> --- a/tools/perf/util/xyarray.c
> +++ b/tools/perf/util/xyarray.c
> @@ -1,20 +1,93 @@
> #include "xyarray.h"
> #include "util.h"
>
> -struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size)
> +/*
> + * Add a column for all rows;
> + */
> +int xyarray__append(struct xyarray *xy)
> {
> - size_t row_size = ylen * entry_size;
> - struct xyarray *xy = zalloc(sizeof(*xy) + xlen * row_size);
> + struct xyentry *new_entry;
> + unsigned int x;
> +
> + for (x = 0; x < xy->row_count; x++) {
> + new_entry = zalloc(sizeof(*new_entry));
> + if (new_entry == NULL)
> + return -1;
> +
> + new_entry->contents = zalloc(xy->entry_size);
> + if (new_entry->contents == NULL)
free new_entry on this error path
> + return -1;
>
> - if (xy != NULL) {
> - xy->entry_size = entry_size;
> - xy->row_size = row_size;
> + list_add_tail(&new_entry->next, &xy->rows[x].head);
> }
>
> + return 0;
> +}
> +
> +struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size)
> +{
> + struct xyarray *xy = zalloc(sizeof(*xy) + xlen * sizeof(struct row));
> + int i;
> +
> + if (xy == NULL)
> + return NULL;
> +
> + xy->row_count = xlen;
> + xy->entry_size = entry_size;
> +
> + for (i = 0; i < xlen; i++)
> + INIT_LIST_HEAD(&xy->rows[i].head);
> +
> + for (i = 0; i < ylen; i++)
> + if (xyarray__append(xy) < 0) {
> + xyarray__delete(xy);
> + return NULL;
> + }
> +
> return xy;
> }
>
> +/*
> + * remove a column for all rows;
> + */
> +int xyarray__remove(struct xyarray *xy, int y)
> +{
> + struct xyentry *entry;
> + unsigned int x;
> + int count;
> +
> + if (!xy)
> + return 0;
> +
> + for (x = 0; x < xy->row_count; x++) {
> + count = 0;
> + list_for_each_entry(entry, &xy->rows[x].head, next)
> + if (count++ == y) {
> + list_del(&entry->next);
> + free(entry);
> + return 0;
> + }
braces are needed around the list_for_each block.
> + }
> +
> + return -1;
> +}
> +
> +/*
> + * All nodes in every rows should be deleted before delete @xy.
> + */
> void xyarray__delete(struct xyarray *xy)
> {
> + unsigned int i;
> + struct xyentry *entry;
> +
> + if (!xy)
> + return;
> +
> + for (i = 0; i < xy->row_count; i++)
> + list_for_each_entry(entry, &xy->rows[i].head, next) {
> + list_del(&entry->next);
> + free(entry);
> + }
> +
> free(xy);
> }
> diff --git a/tools/perf/util/xyarray.h b/tools/perf/util/xyarray.h
> index c488a07..07fa370 100644
> --- a/tools/perf/util/xyarray.h
> +++ b/tools/perf/util/xyarray.h
> @@ -2,19 +2,38 @@
> #define _PERF_XYARRAY_H_ 1
>
> #include <sys/types.h>
> +#include <linux/list.h>
> +
> +struct row {
> + struct list_head head;
> +};
> +
> +struct xyentry {
> + struct list_head next;
> + char *contents;
> +};
>
> struct xyarray {
> - size_t row_size;
> + size_t row_count;
> size_t entry_size;
> - char contents[];
> + struct row rows[];
> };
>
> struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size);
> void xyarray__delete(struct xyarray *xy);
> +int xyarray__append(struct xyarray *xy);
> +int xyarray__remove(struct xyarray *xy, int y);
>
> static inline void *xyarray__entry(struct xyarray *xy, int x, int y)
> {
> - return &xy->contents[x * xy->row_size + y * xy->entry_size];
> + struct xyentry *entry;
> + int columns = 0;
> +
> + list_for_each_entry(entry, &xy->rows[x].head, next)
> + if (columns++ == y)
> + return entry->contents;
braces needed around multi-statement block
I'll review next patches as I get time.
David
> +
> + return NULL;
> }
>
> #endif /* _PERF_XYARRAY_H_ */
>
--
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