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Re: [libvirt] [RFC] [PATCH v3 5/6] make /proc/meminfo isolate with host through fuse



于 2012年09月26日 02:45, Daniel P. Berrange 写道:
> On Tue, Sep 11, 2012 at 10:54:51AM +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 |  151 +++++++++++++++++++++++++++++++++++
>>  src/lxc/lxc_cgroup.h |    1 +
>>  src/lxc/lxc_fuse.c   |  216 +++++++++++++++++++++++++++++++++++++++++++++++--
>>  src/lxc/lxc_fuse.h   |   14 +++
>>  4 files changed, 373 insertions(+), 9 deletions(-)
>>
>> diff --git a/src/lxc/lxc_cgroup.c b/src/lxc/lxc_cgroup.c
>> index aca6309..2fd1b10 100644
>> --- a/src/lxc/lxc_cgroup.c
>> +++ b/src/lxc/lxc_cgroup.c
>> @@ -23,6 +23,8 @@
>>  
>>  #include "lxc_cgroup.h"
>>  #include "lxc_container.h"
>> +#include "lxc_fuse.h"
>> +#include "virfile.h"
>>  #include "virterror_internal.h"
>>  #include "logging.h"
>>  #include "memory.h"
>> @@ -138,6 +140,155 @@ cleanup:
>>  }
>>  
>>  
>> +static int virLXCCgroupGetMemSwapUsage(virCgroupPtr cgroup,
>> +                                       unsigned long long *usage)
>> +{
>> +    return virCgroupGetMemSwapUsage(cgroup, usage);
>> +}
>> +
>> +
>> +static int virLXCCgroupGetMemSwapTotal(virCgroupPtr cgroup,
>> +                                       unsigned long long *total)
>> +{
>> +    return virCgroupGetMemSwapHardLimit(cgroup, total);
>> +}
>> +
>> +
>> +static int virLXCCgroupGetMemUsage(virCgroupPtr cgroup,
>> +                                   unsigned long long *usage)
>> +{
>> +    int ret;
>> +    unsigned long memUsage;
>> +
>> +    ret = virCgroupGetMemoryUsage(cgroup, &memUsage);
>> +    *usage = (unsigned long long) memUsage;
>> +
>> +    return ret;
>> +}
>> +
>> +
>> +static int virLXCCgroupGetMemTotal(virCgroupPtr cgroup,
>> +                                   unsigned long long *total)
>> +{
>> +    return virCgroupGetMemoryHardLimit(cgroup, total);
>> +}
>> +
>> +
>> +static int virLXCCgroupGetMemStat(virCgroupPtr cgroup,
>> +                                  unsigned long long *meminfo)
>> +{
>> +    int ret = 0;
>> +    FILE *statfd = NULL;
>> +    char *statFile = NULL;
>> +    char line[1024];
>> +
>> +    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 = -ENOENT;
>> +        goto out_free;
>> +    }
>> +
>> +    while (fgets(line, sizeof(line), statfd) != NULL) {
>> +        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 ((ret = virStrToLong_ull(value + 1, NULL, 10, &stat_value)) < 0)
>> +            goto out;
>> +
>> +        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;
>> +out:
>> +    VIR_FORCE_FCLOSE(statfd);
>> +out_free:
>> +    VIR_FREE(statFile);
>> +    return ret;
>> +}
>> +
>> +
>> +int virLXCCgroupGetMeminfo(unsigned long long *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 out;
>> +    }
>> +
>> +    ret = virLXCCgroupGetMemTotal(cgroup, &meminfo[MEMTOTAL]);
>> +    if (ret < 0) {
>> +        virReportSystemError(-ret, "%s",
>> +                             _("Unable to get memory cgroup total"));
>> +        goto out;
>> +    }
>> +
>> +    ret = virLXCCgroupGetMemUsage(cgroup, &meminfo[MEMUSAGE]);
>> +    if (ret < 0) {
>> +        virReportSystemError(-ret, "%s",
>> +                             _("Unable to get memory cgroup stat usage"));
>> +        goto out;
>> +    }
>> +
>> +    ret = virLXCCgroupGetMemSwapTotal(cgroup, &meminfo[SWAPTOTAL]);
>> +    if (ret < 0) {
>> +        virReportSystemError(-ret, "%s",
>> +                             _("Unable to get memory cgroup stat swaptotal"));
>> +        goto out;
>> +    }
>> +
>> +    ret = virLXCCgroupGetMemSwapUsage(cgroup, &meminfo[SWAPUSAGE]);
>> +    if (ret < 0) {
>> +        virReportSystemError(-ret, "%s",
>> +                             _("Unable to get memory cgroup stat swapusage"));
>> +        goto out;
>> +    }
>> +
>> +    ret = 0;
>> +out:
>> +    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 8ff1015..eccdcba 100644
>> --- a/src/lxc/lxc_cgroup.h
>> +++ b/src/lxc/lxc_cgroup.h
>> @@ -25,5 +25,6 @@
>>  # include "domain_conf.h"
>>  
>>  int virLXCCgroupSetup(virDomainDefPtr def);
>> +int virLXCCgroupGetMeminfo(unsigned long long *meminfo);
>>  
>>  #endif /* __VIR_LXC_CGROUP_H__ */
>> diff --git a/src/lxc/lxc_fuse.c b/src/lxc/lxc_fuse.c
>> index 868a698..a073e30 100644
>> --- a/src/lxc/lxc_fuse.c
>> +++ b/src/lxc/lxc_fuse.c
>> @@ -29,25 +29,48 @@
>>  #include <sys/mount.h>
>>  
>>  #include "lxc_fuse.h"
>> +#include "lxc_cgroup.h"
>>  #include "virterror_internal.h"
>> +#include "virfile.h"
>>  
>>  #define VIR_FROM_THIS VIR_FROM_LXC
>>  
>>  #if HAVE_FUSE
>>  
>> +static const char *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 ((res = virAsprintf(&mempath, "/proc/%s", path)) < 0) {
>> +        virReportOOMError();
>> +        return res;
>> +    }
>> +
>> +    res = 0;
>>  
>>      if (STREQ(path, "/")) {
>>          stbuf->st_mode = S_IFDIR | 0755;
>>          stbuf->st_nlink = 2;
>> +    } else if (STREQ(path, meminfo_path)) {
>> +        stat(mempath, &sb);
>> +        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;
>>      }
>>  
>> +    VIR_FREE(mempath);
>>      return res;
>>  }
>>  
>> @@ -61,23 +84,198 @@ static int lxcProcReaddir(const char *path, void *buf,
>>  
>>      filler(buf, ".", NULL, 0);
>>      filler(buf, "..", NULL, 0);
>> +    filler(buf, meminfo_path + 1, NULL, 0);
>>  
>>      return 0;
>>  }
>>  
>> -static int lxcProcOpen(const char *path ATTRIBUTE_UNUSED,
>> -                       struct fuse_file_info *fi ATTRIBUTE_UNUSED)
>> +static int lxcProcOpen(const char *path,
>> +                       struct fuse_file_info *fi)
>> +{
>> +    if (!STREQ(path, 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)
>>  {
>> -    return -ENOENT;
>> +    int fd;
>> +    int res;
>> +
>> +    fd = open(path, O_RDONLY);
>> +    if (fd == -1)
>> +        return -errno;
>> +
>> +    res = pread(fd, buf, size, offset);
>> +    if (res == -1)
>> +        res = -errno;
>> +
>> +    VIR_FORCE_CLOSE(fd);
>> +    return res;
>>  }
>>  
>> -static int lxcProcRead(const char *path ATTRIBUTE_UNUSED,
>> -                       char *buf ATTRIBUTE_UNUSED,
>> -                       size_t size ATTRIBUTE_UNUSED,
>> -                       off_t offset ATTRIBUTE_UNUSED,
>> +static int lxcProcReadMeminfo(char *hostpath, virDomainDefPtr def,
>> +                              char *buf, size_t size, off_t offset)
>> +{
>> +    int copied = 0;
>> +    int res = 0;
>> +    FILE *fd = NULL;
>> +    char line[1024];
>> +    unsigned long long meminfo[MEMMAX];
>> +    memset(meminfo, 0, sizeof(meminfo));
>> +
>> +    if ((res = virLXCCgroupGetMeminfo(meminfo)) < 0)
>> +        return res;
>> +
>> +    fd = fopen(hostpath, "r");
>> +    if (fd == NULL) {
>> +        virReportSystemError(errno, _("Cannot open %s"), hostpath);
>> +        res = -errno;
>> +        goto out;
>> +    }
>> +
>> +    fseek(fd, offset, SEEK_SET);
>> +
>> +    while (copied < size && fgets(line, sizeof(line), fd) != NULL) {
>> +        int len = 0;
>> +        char *new_line = NULL;
>> +        char *ptr = strchr(line, ':');
>> +        if (ptr) {
>> +            *ptr = '\0';
>> +            new_line = line;
>> +
>> +            if (STREQ(line, "MemTotal") &&
>> +                (def->mem.hard_limit || def->mem.max_balloon)) {
>> +                if ((res = virAsprintf(&new_line, "MemTotal:       %8llu KB\n",
>> +                                       meminfo[MEMTOTAL])) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "MemFree") &&
>> +                       (def->mem.hard_limit || def->mem.max_balloon)) {
>> +                if ((res = virAsprintf(&new_line, "MemFree:        %8llu KB\n",
>> +                                (meminfo[MEMTOTAL] - meminfo[MEMUSAGE]))) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Buffers")) {
>> +                if ((res = virAsprintf(&new_line, "Buffers:        %8d KB\n", 0)) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Cached")) {
>> +                if ((res = virAsprintf(&new_line, "Cached:         %8llu KB\n",
>> +                                       meminfo[CACHED])) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Active")) {
>> +                if ((res = virAsprintf(&new_line, "Active:         %8llu KB\n",
>> +                                (meminfo[ACTIVE_ANON] + meminfo[ACTIVE_FILE]))) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Inactive")) {
>> +                if ((res = virAsprintf(&new_line, "Inactive:       %8llu KB\n",
>> +                                (meminfo[INACTIVE_ANON] + meminfo[INACTIVE_FILE]))) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Active(anon)")) {
>> +                if ((res = virAsprintf(&new_line, "Active(anon):   %8llu KB\n",
>> +                                       meminfo[ACTIVE_ANON])) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Inactive(anon)")) {
>> +                if ((res = virAsprintf(&new_line, "Inactive(anon): %8llu KB\n",
>> +                                       meminfo[INACTIVE_ANON])) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Active(file)")) {
>> +                if ((res = virAsprintf(&new_line, "Active(file):   %8llu KB\n",
>> +                                       meminfo[ACTIVE_FILE])) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Inactive(file)")) {
>> +                if ((res = virAsprintf(&new_line, "Inactive(file): %8llu KB\n",
>> +                                       meminfo[INACTIVE_FILE])) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "Unevictable")) {
>> +                if ((res = virAsprintf(&new_line, "Unevictable:    %8llu KB\n",
>> +                                       meminfo[UNEVICTABLE])) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "SwapTotal") && def->mem.swap_hard_limit) {
>> +                if ((res = virAsprintf(&new_line, "SwapTotal:      %8llu KB\n",
>> +                                (meminfo[SWAPTOTAL] - meminfo[MEMTOTAL]))) < 0){
>> +                    goto out_oom;
>> +                }
>> +            } else if (STREQ(line, "SwapFree") && def->mem.swap_hard_limit) {
>> +                if ((res = virAsprintf(&new_line, "SwapFree:       %8llu KB\n",
>> +                            (meminfo[SWAPTOTAL] - meminfo[MEMTOTAL] -
>> +                            meminfo[SWAPUSAGE] + meminfo[MEMUSAGE]))) < 0) {
>> +                    goto out_oom;
>> +                }
>> +            }
>> +            *ptr=':';
>> +        }
>> +
>> +        len = strlen(new_line);
>> +
>> +        if (copied + len > size)
>> +            len = size - copied;
>> +
>> +        memcpy(buf + copied, new_line, len);
>> +        copied += len;
>> +        memset(line, 0, sizeof(line));
>> +        if (new_line != line)
>> +            VIR_FREE(new_line);
>> +    }
>> +    res = copied;
>> +
>> +out:
>> +    VIR_FORCE_FCLOSE(fd);
>> +    return res;
>> +
>> +out_oom:
>> +    virReportOOMError();
>> +    goto out;
>> +}
>> +
>> +static int lxcProcRead(const char *path,
>> +                       char *buf,
>> +                       size_t size,
>> +                       off_t offset,
>>                         struct fuse_file_info *fi ATTRIBUTE_UNUSED)
>>  {
>> -    return -ENOENT;
>> +    int res = 0;
>> +    char *hostpath = NULL;
>> +    struct fuse_context *context = NULL;
>> +    virDomainDefPtr def = NULL;
>> +
>> +    if ((res = virAsprintf(&hostpath, "/proc/%s", path)) < 0) {
>> +        virReportOOMError();
>> +        return res;
>> +    }
>> +
>> +    context = fuse_get_context();
>> +    def = (virDomainDefPtr)context->private_data;
>> +
>> +    if (STREQ(path, meminfo_path)) {
>> +        res = lxcProcReadMeminfo(hostpath, def, buf, size, offset);
>> +    } else {
>> +        res = -ENOENT;
>> +        goto out;
>> +    }
> 
> The second branch suggests that we should be returning errno values
> upon failure. At least one code path in lxcProcReadMeminfo instead
> returns simply -1. This code should all use normal libvirt error
> reporting APIs and return -1 on error. Then right at the end of this
> method, if res == -1, then use virGetLastError() to fetch any
> virErrorPtr object. If the code == VIR_ERR_SYSTEM_ERROR then you
> can get the errno value from the 'int1' field in virErrorPtr.
> Otherwise you can just use EIO
> 

Get it,thanks for thanks for telling me this. :)

>> +
>> +    if (res < 0) {
>> +        if((res = lxcProcHostRead(hostpath, buf, size, offset)) < 0)
>> +            virReportSystemError(errno, "%s",
>> +                                 _("failed to show host's meminfo"));
>> +    }
>> +
>> +out:
>> +    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 d60c238..7db534b 100644
>> --- a/src/lxc/lxc_fuse.h
>> +++ b/src/lxc/lxc_fuse.h
>> @@ -35,6 +35,20 @@
>>  #include "util.h"
>>  #include "memory.h"
>>  
>> +enum {
>> +    MEMTOTAL,
>> +    MEMUSAGE,
>> +    CACHED,
>> +    ACTIVE_ANON,
>> +    INACTIVE_ANON,
>> +    ACTIVE_FILE,
>> +    INACTIVE_FILE,
>> +    UNEVICTABLE,
>> +    SWAPTOTAL,
>> +    SWAPUSAGE,
>> +    MEMMAX,
>> +};
> 
> Please use a prefix on any constants, ie  VIR_LXC_FUSE_MEMTOTAL

will fix this.


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