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Re: [libvirt] [PATCH RESEND V8 5/6] make /proc/meminfo isolate with host through fuse



On Mon, Nov 12, 2012 at 07:52:01PM +0800, Gao feng wrote:
> with this patch,container's meminfo will be shown based on
> containers' mem cgroup.
> 
> Right now,it's impossible to virtualize all values in meminfo,
> I collect some values such as MemTotal,MemFree,Cached,Active,
> Inactive,Active(anon),Inactive(anon),Active(file),Inactive(anon),
> Active(file),Inactive(file),Unevictable,SwapTotal,SwapFree.
> 
> if I miss something, please let me know.
> 
> Signed-off-by: Gao feng <gaofeng cn fujitsu com>
> ---
>  src/lxc/lxc_cgroup.c |  143 ++++++++++++++++++++++++++++++++++++++++
>  src/lxc/lxc_cgroup.h |    3 +-
>  src/lxc/lxc_fuse.c   |  178 ++++++++++++++++++++++++++++++++++++++++++++++++--
>  src/lxc/lxc_fuse.h   |   14 ++++
>  4 files changed, 332 insertions(+), 6 deletions(-)
> 
> diff --git a/src/lxc/lxc_cgroup.c b/src/lxc/lxc_cgroup.c
> index 9a5ba1a..4c32368 100644
> --- a/src/lxc/lxc_cgroup.c
> +++ b/src/lxc/lxc_cgroup.c
> @@ -23,6 +23,7 @@
>  
>  #include "lxc_cgroup.h"
>  #include "lxc_container.h"
> +#include "virfile.h"
>  #include "virterror_internal.h"
>  #include "logging.h"
>  #include "memory.h"
> @@ -138,6 +139,148 @@ cleanup:
>  }
>  
>  
> +static int virLXCCgroupGetMemSwapUsage(virCgroupPtr cgroup,
> +                                       virLXCMeminfoPtr meminfo)
> +{
> +    return virCgroupGetMemSwapUsage(cgroup, &meminfo->swapusage);
> +}
> +
> +
> +static int virLXCCgroupGetMemSwapTotal(virCgroupPtr cgroup,
> +                                       virLXCMeminfoPtr meminfo)
> +{
> +    return virCgroupGetMemSwapHardLimit(cgroup, &meminfo->swaptotal);
> +}
> +
> +
> +static int virLXCCgroupGetMemUsage(virCgroupPtr cgroup,
> +                                   virLXCMeminfoPtr meminfo)
> +{
> +    int ret;
> +    unsigned long memUsage;
> +
> +    ret = virCgroupGetMemoryUsage(cgroup, &memUsage);
> +    meminfo->memusage = (unsigned long long) memUsage;
> +
> +    return ret;
> +}
> +
> +
> +static int virLXCCgroupGetMemTotal(virCgroupPtr cgroup,
> +                                   virLXCMeminfoPtr meminfo)
> +{
> +    return virCgroupGetMemoryHardLimit(cgroup, &meminfo->memtotal);
> +}
> +
> +
> +static int virLXCCgroupGetMemStat(virCgroupPtr cgroup,
> +                                  virLXCMeminfoPtr meminfo)
> +{
> +    int ret = 0;
> +    FILE *statfd = NULL;
> +    char *statFile = NULL;
> +    char *line = NULL;
> +    size_t n;
> +
> +    ret = virCgroupPathOfController(cgroup, VIR_CGROUP_CONTROLLER_MEMORY,
> +                                    "memory.stat", &statFile);
> +    if (ret != 0) {
> +        virReportSystemError(-ret, "%s",
> +                             _("cannot get the path of MEMORY cgroup controller"));
> +        return ret;
> +    }
> +
> +    statfd = fopen(statFile, "r");
> +    if (statfd == NULL) {
> +        ret = -errno;
> +        goto cleanup;
> +    }
> +
> +    while (getline(&line, &n, statfd) > 0) {
> +
> +        char *value = strchr(line, ' ');
> +        char *nl = value ? strchr(line, '\n') : NULL;
> +        unsigned long long stat_value;
> +
> +        if (!value)
> +            continue;
> +
> +        if (nl)
> +            *nl = '\0';
> +
> +        *value = '\0';
> +
> +        if (virStrToLong_ull(value + 1, NULL, 10, &stat_value) < 0) {
> +            ret = -EINVAL;
> +            goto cleanup;
> +        }
> +        if (STREQ(line, "cache"))
> +            meminfo->cached = stat_value >> 10;
> +        else if (STREQ(line, "inactive_anon"))
> +            meminfo->inactive_anon = stat_value >> 10;
> +        else if (STREQ(line, "active_anon"))
> +            meminfo->active_anon = stat_value >> 10;
> +        else if (STREQ(line, "inactive_file"))
> +            meminfo->inactive_file = stat_value >> 10;
> +        else if (STREQ(line, "active_file"))
> +            meminfo->active_file = stat_value >> 10;
> +        else if (STREQ(line, "unevictable"))
> +            meminfo->unevictable = stat_value >> 10;
> +    }
> +    ret = 0;
> +
> +cleanup:
> +    VIR_FREE(line);
> +    VIR_FREE(statFile);
> +    VIR_FORCE_FCLOSE(statfd);
> +    return ret;
> +}
> +
> +
> +int virLXCCgroupGetMeminfo(virLXCMeminfoPtr meminfo)
> +{
> +    int ret;
> +    virCgroupPtr cgroup;
> +
> +    ret = virCgroupGetAppRoot(&cgroup);
> +    if (ret < 0) {
> +        virReportSystemError(-ret, "%s",
> +                             _("Unable to get cgroup for container"));
> +        return ret;
> +    }
> +
> +    ret = virLXCCgroupGetMemStat(cgroup, meminfo);
> +    if (ret < 0) {
> +        virReportSystemError(-ret, "%s",
> +                             _("Unable to get memory cgroup stat info"));
> +        goto cleanup;
> +    }
> +
> +    ret = virLXCCgroupGetMemTotal(cgroup, meminfo);
> +    if (ret < 0) {
> +        virReportSystemError(-ret, "%s",
> +                             _("Unable to get memory cgroup total"));
> +        goto cleanup;
> +    }
> +
> +    ret = virLXCCgroupGetMemUsage(cgroup, meminfo);
> +    if (ret < 0) {
> +        virReportSystemError(-ret, "%s",
> +                             _("Unable to get memory cgroup stat usage"));
> +        goto cleanup;
> +    }
> +
> +    virLXCCgroupGetMemSwapTotal(cgroup, meminfo);
> +    virLXCCgroupGetMemSwapUsage(cgroup, meminfo);
> +
> +    ret = 0;
> +cleanup:
> +    virCgroupFree(&cgroup);
> +    return ret;
> +}
> +
> +
> +
>  typedef struct _virLXCCgroupDevicePolicy virLXCCgroupDevicePolicy;
>  typedef virLXCCgroupDevicePolicy *virLXCCgroupDevicePolicyPtr;
>  
> diff --git a/src/lxc/lxc_cgroup.h b/src/lxc/lxc_cgroup.h
> index 6fc68df..6961943 100644
> --- a/src/lxc/lxc_cgroup.h
> +++ b/src/lxc/lxc_cgroup.h
> @@ -23,7 +23,8 @@
>  # define __VIR_LXC_CGROUP_H__
>  
>  # include "domain_conf.h"
> +# include "lxc_fuse.h"
>  
>  int virLXCCgroupSetup(virDomainDefPtr def);
> -
> +int virLXCCgroupGetMeminfo(virLXCMeminfoPtr meminfo);
>  #endif /* __VIR_LXC_CGROUP_H__ */
> diff --git a/src/lxc/lxc_fuse.c b/src/lxc/lxc_fuse.c
> index 6d621ee..5a514d6 100644
> --- a/src/lxc/lxc_fuse.c
> +++ b/src/lxc/lxc_fuse.c
> @@ -30,26 +30,54 @@
>  #include <mntent.h>
>  
>  #include "lxc_fuse.h"
> +#include "lxc_cgroup.h"
>  #include "virterror_internal.h"
>  #include "logging.h"
> +#include "virfile.h"
> +#include "buf.h"
>  
>  #define VIR_FROM_THIS VIR_FROM_LXC
>  
>  #if HAVE_FUSE
>  
> +static const char *fuse_meminfo_path = "/meminfo";
> +
>  static int lxcProcGetattr(const char *path, struct stat *stbuf)
>  {
> -    int res = 0;
> +    int res;
> +    char *mempath = NULL;
> +    struct stat sb;
>  
>      memset(stbuf, 0, sizeof(struct stat));
> +    if (virAsprintf(&mempath, "/proc/%s", path) < 0) {
> +        virReportOOMError();
> +        return -errno;
> +    }
> +
> +    res = 0;
>  
>      if (STREQ(path, "/")) {
>          stbuf->st_mode = S_IFDIR | 0755;
>          stbuf->st_nlink = 2;
> -    } else {
> +    } else if (STREQ(path, fuse_meminfo_path)) {
> +        if (stat(mempath, &sb) < 0) {
> +            res = -errno;
> +            goto cleanup;
> +        }
> +
> +        stbuf->st_mode = sb.st_mode;
> +        stbuf->st_nlink = 1;
> +        stbuf->st_blksize = sb.st_blksize;
> +        stbuf->st_blocks = sb.st_blocks;
> +        stbuf->st_size = sb.st_size;
> +        stbuf->st_atime = sb.st_atime;
> +        stbuf->st_ctime = sb.st_ctime;
> +        stbuf->st_mtime = sb.st_mtime;
> +    } else
>          res = -ENOENT;
> -    }
>  
> +cleanup:
> +    VIR_FREE(mempath);
>      return res;
>  }
>  
> @@ -63,6 +91,7 @@ static int lxcProcReaddir(const char *path, void *buf,
>  
>      filler(buf, ".", NULL, 0);
>      filler(buf, "..", NULL, 0);
> +    filler(buf, fuse_meminfo_path + 1, NULL, 0);
>  
>      return 0;
>  }
> @@ -70,7 +99,127 @@ static int lxcProcReaddir(const char *path, void *buf,
>  static int lxcProcOpen(const char *path ATTRIBUTE_UNUSED,
>                         struct fuse_file_info *fi ATTRIBUTE_UNUSED)
>  {
> -    return -ENOENT;
> +    if (!STREQ(path, fuse_meminfo_path))
> +        return -ENOENT;
> +
> +    if ((fi->flags & 3) != O_RDONLY)
> +        return -EACCES;
> +
> +    return 0;
> +}
> +
> +static int lxcProcHostRead(char *path, char *buf, size_t size, off_t offset)
> +{
> +    int fd;
> +    int res;
> +
> +    fd = open(path, O_RDONLY);
> +    if (fd == -1)
> +        return -errno;
> +
> +    if ((res = pread(fd, buf, size, offset)) < 0)
> +        res = -errno;
> +
> +    VIR_FORCE_CLOSE(fd);
> +    return res;
> +}
> +
> +static int lxcProcReadMeminfo(char *hostpath, virDomainDefPtr def,
> +                              char *buf, size_t size, off_t offset)
> +{
> +    int copied = 0;
> +    int res;
> +    FILE *fd = NULL;
> +    char *line = NULL;
> +    size_t n;
> +    struct virLXCMeminfo meminfo;
> +    virBuffer buffer = VIR_BUFFER_INITIALIZER;
> +    virBufferPtr new_meminfo = &buffer;
> +
> +    if ((res = virLXCCgroupGetMeminfo(&meminfo)) < 0)
> +        return res;
> +
> +    fd = fopen(hostpath, "r");
> +    if (fd == NULL) {
> +        virReportSystemError(errno, _("Cannot open %s"), hostpath);
> +        res = -errno;
> +        goto cleanup;
> +    }
> +
> +    if (fseek(fd, offset, SEEK_SET) < 0) {
> +        virReportSystemError(errno, "%s", _("fseek failed"));
> +        res = -errno;
> +        goto cleanup;
> +    }
> +
> +    res = -1;
> +    while (copied < size && getline(&line, &n, fd) > 0) {
> +        char *ptr = strchr(line, ':');
> +        if (ptr) {
> +            *ptr = '\0';
> +
> +            if (STREQ(line, "MemTotal") &&
> +                (def->mem.hard_limit || def->mem.max_balloon))
> +                virBufferAsprintf(new_meminfo, "MemTotal:       %8llu KB\n",
> +                                  meminfo.memtotal);
> +            else if (STREQ(line, "MemFree") &&
> +                       (def->mem.hard_limit || def->mem.max_balloon))
> +                virBufferAsprintf(new_meminfo, "MemFree:        %8llu KB\n",
> +                                  (meminfo.memtotal - meminfo.memusage));
> +            else if (STREQ(line, "Buffers"))
> +                virBufferAsprintf(new_meminfo, "Buffers:        %8d KB\n", 0);
> +            else if (STREQ(line, "Cached"))
> +                virBufferAsprintf(new_meminfo, "Cached:         %8llu KB\n",
> +                                  meminfo.cached);
> +            else if (STREQ(line, "Active"))
> +                virBufferAsprintf(new_meminfo, "Active:         %8llu KB\n",
> +                                  (meminfo.active_anon + meminfo.active_file));
> +            else if (STREQ(line, "Inactive"))
> +                virBufferAsprintf(new_meminfo, "Inactive:       %8llu KB\n",
> +                                  (meminfo.inactive_anon + meminfo.inactive_file));
> +            else if (STREQ(line, "Active(anon)"))
> +                virBufferAsprintf(new_meminfo, "Active(anon):   %8llu KB\n",
> +                                  meminfo.active_anon);
> +            else if (STREQ(line, "Inactive(anon)"))
> +                virBufferAsprintf(new_meminfo, "Inactive(anon): %8llu KB\n",
> +                                  meminfo.inactive_anon);
> +            else if (STREQ(line, "Active(file)"))
> +                virBufferAsprintf(new_meminfo, "Active(file):   %8llu KB\n",
> +                                  meminfo.active_file);
> +            else if (STREQ(line, "Inactive(file)"))
> +                virBufferAsprintf(new_meminfo, "Inactive(file): %8llu KB\n",
> +                                  meminfo.inactive_file);
> +            else if (STREQ(line, "Unevictable"))
> +                virBufferAsprintf(new_meminfo, "Unevictable:    %8llu KB\n",
> +                                  meminfo.unevictable);
> +            else if (STREQ(line, "SwapTotal") && def->mem.swap_hard_limit)
> +                virBufferAsprintf(new_meminfo, "SwapTotal:      %8llu KB\n",
> +                                  (meminfo.swaptotal - meminfo.memtotal));
> +            else if (STREQ(line, "SwapFree") && def->mem.swap_hard_limit)
> +                virBufferAsprintf(new_meminfo, "SwapFree:       %8llu KB\n",
> +                                  (meminfo.swaptotal - meminfo.memtotal -
> +                                   meminfo.swapusage + meminfo.memusage));
> +            else {
> +                *ptr = ':';
> +                virBufferAdd(new_meminfo, line, -1);
> +            }
> +
> +            if (virBufferError(new_meminfo))
> +                goto cleanup;
> +
> +            copied += strlen(line);
> +            if (copied > size)
> +                copied = size;
> +        }
> +    }
> +    res = copied;
> +    memcpy(buf, virBufferCurrentContent(new_meminfo), copied);
> +
> +cleanup:
> +    VIR_FREE(line);
> +    virBufferFreeAndReset(new_meminfo);
> +    VIR_FORCE_FCLOSE(fd);
> +    return res;
>  }
>  
>  static int lxcProcRead(const char *path ATTRIBUTE_UNUSED,
> @@ -79,7 +228,26 @@ static int lxcProcRead(const char *path ATTRIBUTE_UNUSED,
>                         off_t offset ATTRIBUTE_UNUSED,
>                         struct fuse_file_info *fi ATTRIBUTE_UNUSED)
>  {
> -    return -ENOENT;
> +    int res = -ENOENT;
> +    char *hostpath = NULL;
> +    struct fuse_context *context = NULL;
> +    virDomainDefPtr def = NULL;
> +
> +    if (virAsprintf(&hostpath, "/proc/%s", path) < 0) {
> +        virReportOOMError();
> +        return -errno;
> +    }
> +
> +    context = fuse_get_context();
> +    def = (virDomainDefPtr)context->private_data;
> +
> +    if (STREQ(path, fuse_meminfo_path)) {
> +        if ((res = lxcProcReadMeminfo(hostpath, def, buf, size, offset)) < 0)
> +            res = lxcProcHostRead(hostpath, buf, size, offset);
> +    }
> +
> +    VIR_FREE(hostpath);
> +    return res;
>  }
>  
>  static struct fuse_operations lxcProcOper = {
> diff --git a/src/lxc/lxc_fuse.h b/src/lxc/lxc_fuse.h
> index f2d2cbb..93a5373 100644
> --- a/src/lxc/lxc_fuse.h
> +++ b/src/lxc/lxc_fuse.h
> @@ -35,6 +35,20 @@
>  #include "util.h"
>  #include "memory.h"
>  
> +struct virLXCMeminfo {
> +    unsigned long long memtotal;
> +    unsigned long long memusage;
> +    unsigned long long cached;
> +    unsigned long long active_anon;
> +    unsigned long long inactive_anon;
> +    unsigned long long active_file;
> +    unsigned long long inactive_file;
> +    unsigned long long unevictable;
> +    unsigned long long swaptotal;
> +    unsigned long long swapusage;
> +};
> +typedef struct virLXCMeminfo *virLXCMeminfoPtr;
> +
>  struct virLXCFuse {
>      virDomainDefPtr def;
>      virThread thread;
> -- 
> 1.7.7.6

This seems better from a pure coding point of view.  I can't
really comment on whether the code actually works since I'm
not using LXC over here.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org


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