From 02b25a2eec7c48bcc67f160fc0b911bcf174e8a9 Mon Sep 17 00:00:00 2001 From: Jim Warner Date: Tue, 21 Jul 2015 00:00:00 -0500 Subject: [PATCH] library: vmstat redesign now using 'stack' vs. 'chain' In addition to that text shown below the line which is common to several commit messages, this patch contains several minor changes with lessor impact upon the API: . Standard copyright boilerplate was added in .c file. . The #include header files are ordered alphabetically now, with all those types separately grouped. . The header file follows the conventions of indenting (by 4 spaces) those parameters too lengthy for 1 line. ------------------------------------------------------ . The former 'chains' have now become 'stacks' without the 'next' pointer in each result struct. The pointers initially seemed to offer some flexibility with memory allocations and benefits for the library access logic. However, user access was always via displacement and a a statically allocated chain was cumbersome to define. . An enumerator ending in '_noop' will no longer serve as a fencepost delimiter. Rather, it has become a much more important and flexible user oriented tool. Adding one or more such 'items' in any items list passed into the library becomes the means of extending the 'stack' to also include user (not just library) data. Any such data is guaranteed to never be altered by the library. . Anticipating PID support, where many different types must be represented in a result structure, we'll adopt a common naming standard. And, while not every results structure currently needs to reflect disparate types a union will be employed so the same dot qualifier ('.') can be used consistently when accessing all such data. Signed-off-by: Jim Warner --- proc/libprocps.sym | 2 +- proc/vmstat.c | 52 +++++++++++++++++++++++++++++++++------------- proc/vmstat.h | 24 ++++++++++++++------- 3 files changed, 54 insertions(+), 24 deletions(-) diff --git a/proc/libprocps.sym b/proc/libprocps.sym index 7f4c30b0..b4d19065 100644 --- a/proc/libprocps.sym +++ b/proc/libprocps.sym @@ -78,7 +78,7 @@ global: procps_vmstat_ref; procps_vmstat_unref; procps_vmstat_get; - procps_vmstat_get_chain; + procps_vmstat_getstack; local: *; }; diff --git a/proc/vmstat.c b/proc/vmstat.c index 775cf1fd..e3294b48 100644 --- a/proc/vmstat.c +++ b/proc/vmstat.c @@ -1,11 +1,29 @@ +/* + * libprocps - Library to read proc filesystem + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ #include +#include #include #include #include + #include #include -#include #include #include "procps-private.h" @@ -162,36 +180,40 @@ PROCPS_EXPORT unsigned long procps_vmstat_get ( return info->data.pswpin; case PROCPS_VMSTAT_PSWPOUT: return info->data.pswpout; + default: + return 0; } - return 0; } -PROCPS_EXPORT int procps_vmstat_get_chain ( +PROCPS_EXPORT int procps_vmstat_getstack ( struct procps_vmstat *info, - struct vmstat_result *item) + struct vmstat_result *these) { - if (item == NULL) + if (these == NULL) return -EINVAL; - do { - switch (item->item) { + for (;;) { + switch (these->item) { case PROCPS_VMSTAT_PGPGIN: - item->result = info->data.pgpgin; + these->result.ul_int = info->data.pgpgin; break; case PROCPS_VMSTAT_PGPGOUT: - item->result = info->data.pgpgout; + these->result.ul_int = info->data.pgpgout; break; case PROCPS_VMSTAT_PSWPIN: - item->result = info->data.pswpin; + these->result.ul_int = info->data.pswpin; break; case PROCPS_VMSTAT_PSWPOUT: - item->result = info->data.pswpout; + these->result.ul_int = info->data.pswpout; + break; + case PROCPS_VMSTAT_noop: + // don't disturb potential user data in the result struct break; + case PROCPS_VMSTAT_stack_end: + return 0; default: return -EINVAL; } - item = item->next; - } while (item); - - return 0; + ++these; + } } diff --git a/proc/vmstat.h b/proc/vmstat.h index 4b97df45..1179aa3b 100644 --- a/proc/vmstat.h +++ b/proc/vmstat.h @@ -28,16 +28,19 @@ __BEGIN_DECLS enum vmstat_item { - PROCPS_VMSTAT_PGPGIN, - PROCPS_VMSTAT_PGPGOUT, - PROCPS_VMSTAT_PSWPIN, - PROCPS_VMSTAT_PSWPOUT + PROCPS_VMSTAT_PGPGIN, // ul_int + PROCPS_VMSTAT_PGPGOUT, // ul_int + PROCPS_VMSTAT_PSWPIN, // ul_int + PROCPS_VMSTAT_PSWPOUT, // ul_int + PROCPS_VMSTAT_noop, // n/a + PROCPS_VMSTAT_stack_end // n/a }; struct vmstat_result { enum vmstat_item item; - unsigned long result; - struct vmstat_result *next; + union { + unsigned long ul_int; + } result; }; struct procps_vmstat; @@ -48,8 +51,13 @@ int procps_vmstat_read (struct procps_vmstat *info); int procps_vmstat_ref (struct procps_vmstat *info); int procps_vmstat_unref (struct procps_vmstat **info); -unsigned long procps_vmstat_get (struct procps_vmstat *info, enum vmstat_item item); -int procps_vmstat_get_chain (struct procps_vmstat *info, struct vmstat_result *item); +unsigned long procps_vmstat_get ( + struct procps_vmstat *info, + enum vmstat_item item); + +int procps_vmstat_getstack ( + struct procps_vmstat *info, + struct vmstat_result *these); __END_DECLS #endif -- 2.40.0