[libvirt] [PATCH 16/21] resctrl: Add functions to work with resctrl allocations

Monday, 13 November 2017

With this commit we finally have a way to read and manipulate basic resctrl
settings.  Locking is done only on exposed functions that read/write from/to
resctrlfs.  Not in fuctions that are exposed in virresctrlpriv.h as those are
only supposed to be used from tests.

Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com&gt;
---
 src/Makefile.am           |    2 +-
 src/libvirt_private.syms  |   12 +
 src/util/virresctrl.c     | 1012 ++++++++++++++++++++++++++++++++++++++++++++-
 src/util/virresctrl.h     |   59 +++
 src/util/virresctrlpriv.h |   32 ++
 5 files changed, 1115 insertions(+), 2 deletions(-)
 create mode 100644 src/util/virresctrlpriv.h

diff --git a/src/Makefile.am b/src/Makefile.am
index 1d24231249de..ad113262fbb0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -167,7 +167,7 @@ UTIL_SOURCES = \
 		util/virprocess.c util/virprocess.h \
 		util/virqemu.c util/virqemu.h \
 		util/virrandom.h util/virrandom.c \
-		util/virresctrl.h util/virresctrl.c \
+		util/virresctrl.h util/virresctrl.c	util/virresctrlpriv.h	\
 		util/virrotatingfile.h util/virrotatingfile.c \
 		util/virscsi.c util/virscsi.h \
 		util/virscsihost.c util/virscsihost.h \
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index b24728ce4a1d..37bac41e618b 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2532,6 +2532,18 @@ virRandomInt;
 # util/virresctrl.h
 virCacheTypeFromString;
 virCacheTypeToString;
+virResctrlAllocAddPID;
+virResctrlAllocCreate;
+virResctrlAllocForeachSize;
+virResctrlAllocFormat;
+virResctrlAllocGetFree;
+virResctrlAllocMasksAssign;
+virResctrlAllocNewFromInfo;
+virResctrlAllocRemove;
+virResctrlAllocSetID;
+virResctrlAllocSetSize;
+virResctrlAllocUpdateMask;
+virResctrlAllocUpdateSize;
 virResctrlGetInfo;
 virResctrlInfoGetCache;
 
diff --git a/src/util/virresctrl.c b/src/util/virresctrl.c
index 6c6692e78f42..ac1b38436bb2 100644
--- a/src/util/virresctrl.c
+++ b/src/util/virresctrl.c
@@ -23,7 +23,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 
-#include "virresctrl.h"
+#include "virresctrlpriv.h"
 
 #include "c-ctype.h"
 #include "count-one-bits.h"
@@ -151,6 +151,153 @@ virResctrlInfoNew(void)
 }
 
 
+/* Alloc-related definitions and AllocClass-related functions */
+typedef struct _virResctrlAllocPerType virResctrlAllocPerType;
+typedef virResctrlAllocPerType *virResctrlAllocPerTypePtr;
+struct _virResctrlAllocPerType {
+    /* There could be bool saying whether this is set or not, but since everything
+     * in virResctrlAlloc (and most of libvirt) goes with pointer arrays we would
+     * have to have one more level of allocation anyway, so this stays faithful to
+     * the concept */
+    unsigned long long **sizes;
+    size_t nsizes;
+
+    /* Mask for each cache */
+    virBitmapPtr *masks;
+    size_t nmasks;
+};
+
+typedef struct _virResctrlAllocPerLevel virResctrlAllocPerLevel;
+typedef virResctrlAllocPerLevel *virResctrlAllocPerLevelPtr;
+struct _virResctrlAllocPerLevel {
+    virResctrlAllocPerTypePtr *types; /* Indexed with enum virCacheType */
+};
+
+struct _virResctrlAlloc {
+    virObject parent;
+
+    virResctrlAllocPerLevelPtr *levels;
+    size_t nlevels;
+
+    char *id; /* The identifier (any unique string for now) */
+    char *path;
+};
+
+static virClassPtr virResctrlAllocClass;
+
+static void
+virResctrlAllocDispose(void *obj)
+{
+    size_t i = 0;
+    size_t j = 0;
+    size_t k = 0;
+
+    virResctrlAllocPtr resctrl = obj;
+
+    for (i = 0; i < resctrl->nlevels; i++) {
+        virResctrlAllocPerLevelPtr level = resctrl->levels[--resctrl->nlevels];
+
+        if (!level)
+            continue;
+
+        for (j = 0; j < VIR_CACHE_TYPE_LAST; j++) {
+            virResctrlAllocPerTypePtr type = level->types[j];
+
+            if (!type)
+                continue;
+
+            for (k = 0; k < type->nsizes; k++)
+                VIR_FREE(type->sizes[k]);
+
+            VIR_FREE(type->sizes);
+            VIR_FREE(type);
+        }
+        VIR_FREE(level->types);
+        VIR_FREE(level);
+    }
+
+    VIR_FREE(resctrl->id);
+    VIR_FREE(resctrl->levels);
+}
+
+static int virResctrlAllocOnceInit(void)
+{
+    if (!(virResctrlAllocClass = virClassNew(virClassForObject(),
+                                             "virResctrlAlloc",
+                                             sizeof(virResctrlAlloc),
+                                             virResctrlAllocDispose)))
+        return -1;
+
+    return 0;
+}
+
+VIR_ONCE_GLOBAL_INIT(virResctrlAlloc)
+
+static virResctrlAllocPtr
+virResctrlAllocNew(void)
+{
+    if (virResctrlAllocInitialize() < 0)
+        return NULL;
+
+    return virObjectNew(virResctrlAllocClass);
+}
+
+
+/* Common functions */
+static int
+virResctrlLockInternal(int op)
+{
+    int fd = open(SYSFS_RESCTRL_PATH, O_DIRECTORY | O_CLOEXEC);
+
+    if (fd < 0) {
+        virReportSystemError(errno, "%s", _("Cannot open
resctrlfs"));
+        return -1;
+    }
+
+    if (flock(fd, op) < 0) {
+        virReportSystemError(errno, "%s", _("Cannot lock
resctrlfs"));
+        VIR_FORCE_CLOSE(fd);
+        return -1;
+    }
+
+    return fd;
+}
+
+static inline int
+virResctrlLockRead(void)
+{
+    return virResctrlLockInternal(LOCK_SH);
+}
+
+static inline int
+virResctrlLockWrite(void)
+{
+    return virResctrlLockInternal(LOCK_EX);
+}
+
+static int
+virResctrlUnlock(int fd)
+{
+    int ret = -1;
+
+    if (fd == -1)
+        return 0;
+
+    /* The lock gets unlocked by closing the fd, which we need to do anyway in
+     * order to clean up properly */
+    if (VIR_CLOSE(fd) < 0) {
+        virReportSystemError(errno, "%s", _("Cannot close
resctrlfs"));
+
+        /* Trying to save the already broken */
+        if (flock(fd, LOCK_UN) < 0)
+            virReportSystemError(errno, "%s", _("Cannot unlock
resctrlfs"));
+        return -1;
+    }
+
+    return ret;
+}
+
+
 /* Info-related functions */
 int
 virResctrlGetInfo(virResctrlInfoPtr *resctrl)
@@ -318,3 +465,866 @@ virResctrlInfoGetCache(virResctrlInfoPtr resctrl,
     VIR_FREE(*controls);
     goto cleanup;
 }
+
+
+/* Alloc-related functions */
+static virResctrlAllocPerTypePtr
+virResctrlAllocFindType(virResctrlAllocPtr *resctrl,
+                        unsigned int level,
+                        virCacheType type,
+                        bool alloc)
+{
+    virResctrlAllocPerLevelPtr a_level = NULL;
+    virResctrlAllocPtr tmp = NULL;
+
+    if (!*resctrl) {
+        if (!alloc || !(*resctrl = virResctrlAllocNew()))
+            return NULL;
+    }
+
+    tmp = *resctrl;
+
+    /* Per-level array */
+    if (tmp->nlevels <= level) {
+        if (!alloc || VIR_EXPAND_N(tmp->levels, tmp->nlevels,
+                                   level - tmp->nlevels + 1) < 0)
+            return NULL;
+    }
+
+    if (!tmp->levels[level]) {
+        if (!alloc ||
+            VIR_ALLOC(tmp->levels[level]) < 0 ||
+            VIR_ALLOC_N(tmp->levels[level]->types, VIR_CACHE_TYPE_LAST) < 0)
+            return NULL;
+    }
+    a_level = tmp->levels[level];
+
+    if (!a_level->types[type]) {
+        if (!alloc || VIR_ALLOC(a_level->types[type]) < 0)
+            return NULL;
+    }
+
+    return a_level->types[type];
+}
+
+static virBitmapPtr *
+virResctrlAllocFindMask(virResctrlAllocPtr *resctrl,
+                        unsigned int level,
+                        virCacheType type,
+                        unsigned int cache,
+                        bool alloc)
+{
+    virResctrlAllocPerTypePtr a_type = virResctrlAllocFindType(resctrl, level,
+                                                               type, alloc);
+
+    if (!a_type)
+        return NULL;
+
+    if (!a_type->masks) {
+        if (!alloc || VIR_ALLOC_N(a_type->masks, cache + 1) < 0)
+            return NULL;
+        a_type->nmasks = cache + 1;
+    } else if (a_type->nmasks <= cache) {
+        if (!alloc || VIR_EXPAND_N(a_type->masks, a_type->nmasks,
+                                   cache - a_type->nmasks + 1) < 0)
+            return NULL;
+    }
+
+    return a_type->masks + cache;
+}
+
+static unsigned long long *
+virResctrlAllocFindSize(virResctrlAllocPtr *resctrl,
+                        unsigned int level,
+                        virCacheType type,
+                        unsigned int cache,
+                        bool alloc)
+{
+    virResctrlAllocPerTypePtr a_type = virResctrlAllocFindType(resctrl, level,
+                                                               type, alloc);
+
+    if (!a_type)
+        return NULL;
+
+    if (!a_type->sizes) {
+        if (!alloc || VIR_ALLOC_N(a_type->sizes, cache + 1) < 0)
+            return NULL;
+        a_type->nsizes = cache + 1;
+    } else if (a_type->nsizes <= cache) {
+        if (!alloc || VIR_EXPAND_N(a_type->sizes, a_type->nsizes,
+                                   cache - a_type->nsizes + 1) < 0)
+            return NULL;
+    }
+
+    if (!a_type->sizes[cache]) {
+        if (!alloc || VIR_ALLOC(a_type->sizes[cache]) < 0)
+            return NULL;
+    }
+
+    return a_type->sizes[cache];
+}
+
+int
+virResctrlAllocUpdateMask(virResctrlAllocPtr *resctrl,
+                          unsigned int level,
+                          virCacheType type,
+                          unsigned int cache,
+                          virBitmapPtr mask)
+{
+    virBitmapPtr *found = virResctrlAllocFindMask(resctrl, level, type, cache,
+                                                  true);
+
+    if (!found)
+        return -1;
+
+    virBitmapFree(*found);
+
+    *found = virBitmapNew(virBitmapSize(mask));
+    if (!*found)
+        return -1;
+
+    return virBitmapCopy(*found, mask);
+}
+
+int
+virResctrlAllocUpdateSize(virResctrlAllocPtr *resctrl,
+                          unsigned int level,
+                          virCacheType type,
+                          unsigned int cache,
+                          unsigned long long size)
+{
+    unsigned long long *found = virResctrlAllocFindSize(resctrl, level, type,
+                                                        cache, true);
+
+    if (!found)
+        return -1;
+
+    *found = size;
+    return 0;
+}
+
+static bool
+virResctrlAllocCheckCollision(virResctrlAllocPtr a,
+                              unsigned int level,
+                              virCacheType type,
+                              unsigned int cache)
+{
+    /* If there is an allocation for type 'both', there can be no other
+     * allocation for the same cache */
+    if (virResctrlAllocFindSize(&a, level, VIR_CACHE_TYPE_BOTH, cache, false))
+        return true;
+
+    if (type == VIR_CACHE_TYPE_BOTH) {
+        if (virResctrlAllocFindSize(&a, level, VIR_CACHE_TYPE_CODE, cache, false))
+            return true;
+        if (virResctrlAllocFindSize(&a, level, VIR_CACHE_TYPE_DATA, cache, false))
+            return true;
+    }
+
+    /* And never two allocations for the same type */
+    if (virResctrlAllocFindSize(&a, level, type, cache, false))
+        return true;
+
+    return false;
+}
+
+int
+virResctrlAllocSetSize(virResctrlAllocPtr *resctrl,
+                       unsigned int level,
+                       virCacheType type,
+                       unsigned int cache,
+                       unsigned long long size)
+{
+    if (virResctrlAllocCheckCollision(*resctrl, level, type, cache)) {
+        virReportError(VIR_ERR_XML_ERROR,
+                       _("Colliding cache allocations for cache "
+                         "level '%u' id '%u', type
'%s'"),
+                       level, cache, virCacheTypeToString(type));
+        return -1;
+    }
+
+    return virResctrlAllocUpdateSize(resctrl, level, type, cache, size);
+}
+
+int
+virResctrlAllocForeachSize(virResctrlAllocPtr resctrl,
+                           virResctrlAllocForeachSizeCallback cb,
+                           void *opaque)
+{
+    int ret = 0;
+    unsigned int level = 0;
+    unsigned int type = 0;
+    unsigned int cache = 0;
+
+    if (!resctrl)
+        return 0;
+
+    for (level = 0; level < resctrl->nlevels; level++) {
+        virResctrlAllocPerLevelPtr a_level = resctrl->levels[level];
+
+        if (!a_level)
+            continue;
+
+        for (type = 0; type < VIR_CACHE_TYPE_LAST; type++) {
+            virResctrlAllocPerTypePtr a_type = a_level->types[type];
+
+            if (!a_type)
+                continue;
+
+            for (cache = 0; cache < a_type->nsizes; cache++) {
+                unsigned long long *size = a_type->sizes[cache];
+
+                if (!size)
+                    continue;
+
+                ret = cb(level, type, cache, *size, opaque);
+                if (ret < 0)
+                    return ret;
+            }
+        }
+    }
+
+    return 0;
+}
+
+int
+virResctrlAllocSetID(virResctrlAllocPtr alloc,
+                     const char *id)
+{
+    if (!id) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Resctrl allocation id cannot be NULL"));
+        return -1;
+    }
+
+    return VIR_STRDUP(alloc->id, id);
+}
+
+char *
+virResctrlAllocFormat(virResctrlAllocPtr resctrl)
+{
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    unsigned int level = 0;
+    unsigned int type = 0;
+    unsigned int cache = 0;
+
+    if (!resctrl)
+        return NULL;
+
+    for (level = 0; level < resctrl->nlevels; level++) {
+        virResctrlAllocPerLevelPtr a_level = resctrl->levels[level];
+
+        if (!a_level)
+            continue;
+
+        for (type = 0; type < VIR_CACHE_TYPE_LAST; type++) {
+            virResctrlAllocPerTypePtr a_type = a_level->types[type];
+
+            if (!a_type)
+                continue;
+
+            virBufferAsprintf(&buf, "L%u%s:", level,
virResctrlTypeToString(type));
+
+            for (cache = 0; cache < a_type->nmasks; cache++) {
+                virBitmapPtr mask = a_type->masks[cache];
+                char *mask_str = NULL;
+
+                if (!mask)
+                    continue;
+
+                mask_str = virBitmapToString(mask, false, true);
+                if (!mask_str) {
+                    virBufferFreeAndReset(&buf);
+                    return NULL;
+                }
+
+                virBufferAsprintf(&buf, "%u=%s;", cache, mask_str);
+            }
+
+            virBufferTrim(&buf, ";", 1);
+            virBufferAddChar(&buf, '\n');
+        }
+    }
+
+    virBufferCheckError(&buf);
+    return virBufferContentAndReset(&buf);
+}
+
+static int
+virResctrlAllocParseProcessCache(virResctrlAllocPtr *resctrl,
+                                 unsigned int level,
+                                 virCacheType type,
+                                 char *cache)
+{
+    char *tmp = strchr(cache, '=');
+    unsigned int cache_id = 0;
+    virBitmapPtr mask = NULL;
+    int ret = -1;
+
+    if (!tmp)
+        return 0;
+
+    *tmp = '\0';
+    tmp++;
+
+    if (virStrToLong_uip(cache, NULL, 10, &cache_id) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Invalid cache id '%s'"), cache);
+        return -1;
+    }
+
+    mask = virBitmapNewString(tmp);
+    if (!mask)
+        return -1;
+
+    if (virResctrlAllocUpdateMask(resctrl, level, type, cache_id, mask) < 0)
+        goto cleanup;
+
+    ret = 0;
+ cleanup:
+    virBitmapFree(mask);
+    return ret;
+}
+
+static int
+virResctrlAllocParseProcessLine(virResctrlAllocPtr *resctrl,
+                                char *line)
+{
+    char **caches = NULL;
+    char *tmp = NULL;
+    unsigned int level = 0;
+    int type = -1;
+    size_t ncaches = 0;
+    size_t i = 0;
+    int ret = -1;
+
+    /* Skip lines that don't concern caches, e.g. MB: etc. */
+    if (line[0] != 'L')
+        return 0;
+
+    /* And lines that we can't parse too */
+    tmp = strchr(line, ':');
+    if (!tmp)
+        return 0;
+
+    *tmp = '\0';
+    tmp++;
+
+    if (virStrToLong_uip(line + 1, &line, 10, &level) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Cannot parse resctrl schema level '%s'"),
+                       line + 1);
+        return -1;
+    }
+
+    type = virResctrlTypeFromString(line);
+    if (type < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Cannot parse resctrl schema level '%s'"),
+                       line + 1);
+        return -1;
+    }
+
+    caches = virStringSplitCount(tmp, ";", 0, &ncaches);
+    if (!caches)
+        return 0;
+
+    for (i = 0; i < ncaches; i++) {
+        if (virResctrlAllocParseProcessCache(resctrl, level, type, caches[i]) < 0)
+            goto cleanup;
+    }
+
+    ret = 0;
+ cleanup:
+    virStringListFree(caches);
+    return ret;
+}
+
+static int
+virResctrlAllocParse(virResctrlAllocPtr *alloc,
+                     const char *schemata)
+{
+    virResctrlAllocPtr tmp = NULL;
+    char **lines = NULL;
+    size_t nlines = 0;
+    size_t i = 0;
+    int ret = -1;
+
+    lines = virStringSplitCount(schemata, "\n", 0, &nlines);
+    for (i = 0; i < nlines; i++) {
+        if (virResctrlAllocParseProcessLine(&tmp, lines[i]) < 0)
+            goto cleanup;
+    }
+
+    *alloc = tmp;
+    tmp = NULL;
+    ret = 0;
+ cleanup:
+    virStringListFree(lines);
+    virObjectUnref(tmp);
+    return ret;
+}
+
+static void
+virResctrlAllocSubtractPerType(virResctrlAllocPerTypePtr a,
+                               virResctrlAllocPerTypePtr b)
+{
+    size_t i = 0;
+
+    if (!a || !b)
+        return;
+
+    for (i = 0; i < a->nmasks && i < b->nmasks; ++i) {
+        if (a->masks[i] && b->masks[i])
+            virBitmapSubtract(a->masks[i], b->masks[i]);
+    }
+}
+
+static void
+virResctrlAllocSubtract(virResctrlAllocPtr a,
+                        virResctrlAllocPtr b)
+{
+    size_t i = 0;
+    size_t j = 0;
+
+    if (!b)
+        return;
+
+    for (i = 0; i < a->nlevels && b->nlevels; ++i) {
+        if (a->levels[i] && b->levels[i]) {
+            /* Here we rely on all the system allocations to use the same types.
+             * We kind of _hope_ it's the case.  If this is left here until the
+             * review and someone finds it, then suggest only removing this last
+             * sentence. */
+            for (j = 0; j < VIR_CACHE_TYPE_LAST; j++) {
+                virResctrlAllocSubtractPerType(a->levels[i]->types[j],
+                                               b->levels[i]->types[j]);
+            }
+        }
+    }
+}
+
+virResctrlAllocPtr
+virResctrlAllocNewFromInfo(virResctrlInfoPtr info)
+{
+    size_t i = 0;
+    size_t j = 0;
+    size_t k = 0;
+    virResctrlAllocPtr ret = NULL;
+    virBitmapPtr mask = NULL;
+
+    for (i = 0; i < info->nlevels; i++) {
+        virResctrlInfoPerLevelPtr i_level = info->levels[i];
+
+        if (!i_level)
+            continue;
+
+        for (j = 0; j < VIR_CACHE_TYPE_LAST; j++) {
+            virResctrlInfoPerTypePtr i_type = i_level->types[j];
+
+            if (!i_type)
+                continue;
+
+            virBitmapFree(mask);
+            mask = virBitmapNew(i_type->bits);
+            if (!mask)
+                goto error;
+            virBitmapSetAll(mask);
+
+            for (k = 0; k <= i_type->max_cache_id; k++) {
+                if (virResctrlAllocUpdateMask(&ret, i, j, k, mask) < 0)
+                    goto error;
+            }
+        }
+    }
+
+ cleanup:
+    virBitmapFree(mask);
+    return ret;
+ error:
+    virObjectUnref(ret);
+    ret = NULL;
+    goto cleanup;
+}
+
+virResctrlAllocPtr
+virResctrlAllocGetFree(virResctrlInfoPtr resctrl)
+{
+    virResctrlAllocPtr ret = NULL;
+    virResctrlAllocPtr alloc = NULL;
+    virBitmapPtr mask = NULL;
+    struct dirent *ent = NULL;
+    DIR *dirp = NULL;
+    char *schemata = NULL;
+    int rv = -1;
+
+    ret = virResctrlAllocNewFromInfo(resctrl);
+    if (!ret)
+        return NULL;
+
+    if (virFileReadValueString(&schemata,
+                               SYSFS_RESCTRL_PATH
+                               "/schemata") < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Could not read schemata file for the default
group"));
+        goto error;
+    }
+
+    if (virResctrlAllocParse(&alloc, schemata) < 0)
+        goto error;
+    if (!alloc) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("No schemata for default resctrlfs group"));
+        goto error;
+    }
+    virResctrlAllocSubtract(ret, alloc);
+
+    if (virDirOpen(&dirp, SYSFS_RESCTRL_PATH) < 0)
+        goto error;
+
+    while ((rv = virDirRead(dirp, &ent, SYSFS_RESCTRL_PATH)) > 0) {
+        if (ent->d_type != DT_DIR)
+            continue;
+
+        if (STREQ(ent->d_name, "info"))
+            continue;
+
+        VIR_FREE(schemata);
+        if (virFileReadValueString(&schemata,
+                                   SYSFS_RESCTRL_PATH
+                                   "/%s/schemata",
+                                   ent->d_name) < 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("Could not read schemata file for group %s"),
+                           ent->d_name);
+            goto error;
+        }
+
+        virObjectUnref(alloc);
+        alloc = NULL;
+        if (virResctrlAllocParse(&alloc, schemata) < 0)
+            goto error;
+
+        virResctrlAllocSubtract(ret, alloc);
+
+        VIR_FREE(schemata);
+    }
+    if (rv < 0)
+        goto error;
+
+ cleanup:
+    virObjectUnref(alloc);
+    VIR_DIR_CLOSE(dirp);
+    VIR_FREE(schemata);
+    virBitmapFree(mask);
+    return ret;
+
+ error:
+    virObjectUnref(ret);
+    ret = NULL;
+    goto cleanup;
+}
+
+int
+virResctrlAllocMasksAssign(virResctrlInfoPtr r_info,
+                           virResctrlAllocPtr alloc,
+                           void **save_ptr)
+{
+    int ret = -1;
+    unsigned int level = 0;
+    virResctrlAllocPtr alloc_free = NULL;
+
+    if (!r_info) {
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("Resource control is not supported on this host"));
+        return -1;
+    }
+
+    if (!save_ptr) {
+        alloc_free = virResctrlAllocGetFree(r_info);
+    } else {
+        if (!*save_ptr)
+            *save_ptr = virResctrlAllocGetFree(r_info);
+
+        alloc_free = *save_ptr;
+    }
+
+    if (!alloc_free)
+        return -1;
+
+    for (level = 0; level < alloc->nlevels; level++) {
+        virResctrlAllocPerLevelPtr a_level = alloc->levels[level];
+        virResctrlAllocPerLevelPtr f_level = NULL;
+        unsigned int type = 0;
+
+        if (!a_level)
+            continue;
+
+        if (level < alloc_free->nlevels)
+            f_level = alloc_free->levels[level];
+
+        if (!f_level) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("Cache level %d does not support tuning"),
+                           level);
+            goto cleanup;
+        }
+
+        for (type = 0; type < VIR_CACHE_TYPE_LAST; type++) {
+            virResctrlAllocPerTypePtr a_type = a_level->types[type];
+            virResctrlAllocPerTypePtr f_type = f_level->types[type];
+            unsigned int cache = 0;
+
+            if (!a_type)
+                continue;
+
+            if (!f_type) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                               _("Cache level %d does not support tuning for "
+                                 "scope type '%s'"),
+                               level, virCacheTypeToString(type));
+                goto cleanup;
+            }
+
+            for (cache = 0; cache < a_type->nsizes; cache++) {
+                unsigned long long *size = a_type->sizes[cache];
+                virBitmapPtr a_mask = NULL;
+                virBitmapPtr f_mask = f_type->masks[cache];
+                virResctrlInfoPerLevelPtr i_level = r_info->levels[level];
+                virResctrlInfoPerTypePtr i_type = i_level->types[type];
+                unsigned long long granularity;
+                unsigned long long need_bits;
+                size_t i = 0;
+                ssize_t pos = -1;
+                ssize_t last_bits = 0;
+                ssize_t last_pos = -1;
+
+                if (!size)
+                    continue;
+
+                if (cache >= f_type->nmasks) {
+                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                   _("Cache with id %u does not exists for level
%d"),
+                                   cache, level);
+                    goto cleanup;
+                }
+
+                f_mask = f_type->masks[cache];
+                if (!f_mask) {
+                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                   _("Cache level %d id %u does not support tuning
for "
+                                     "scope type '%s'"),
+                                   level, cache, virCacheTypeToString(type));
+                    goto cleanup;
+                }
+
+                granularity = i_type->size / i_type->bits;
+                need_bits = *size / granularity;
+
+                if (*size % granularity) {
+                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                   _("Cache allocation of size %llu is not "
+                                     "divisible by granularity %llu"),
+                                   *size, granularity);
+                    goto cleanup;
+                }
+
+                if (need_bits < i_type->min_cbm_bits) {
+                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                   _("Cache allocation of size %llu is smaller
"
+                                     "than the minimum allowed allocation
%llu"),
+                                   *size, granularity * i_type->min_cbm_bits);
+                    goto cleanup;
+                }
+
+                while ((pos = virBitmapNextSetBit(f_mask, pos)) >= 0) {
+                    ssize_t pos_clear = virBitmapNextClearBit(f_mask, pos);
+                    ssize_t bits;
+
+                    if (pos_clear < 0)
+                        pos_clear = virBitmapSize(f_mask);
+
+                    bits = pos_clear - pos;
+
+                    /* Not enough bits, move on and skip all of them */
+                    if (bits < need_bits) {
+                        pos = pos_clear;
+                        continue;
+                    }
+
+                    /* This fits perfectly */
+                    if (bits == need_bits) {
+                        last_pos = pos;
+                        break;
+                    }
+
+                    /* Remember the smaller region if we already found on before */
+                    if (last_pos < 0 || (last_bits && bits < last_bits)) {
+                        last_bits = bits;
+                        last_pos = pos;
+                    }
+
+                    pos = pos_clear;
+                }
+
+                if (last_pos < 0) {
+                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                   _("Not enough room for allocation of "
+                                     "%llu bytes for level %u cache %u "
+                                     "scope type '%s'"),
+                                   *size, level, cache,
+                                   virCacheTypeToString(type));
+                    goto cleanup;
+                }
+
+                a_mask = virBitmapNew(i_type->bits);
+                for (i = last_pos; i < last_pos + need_bits; i++) {
+                    ignore_value(virBitmapSetBit(a_mask, i));
+                    ignore_value(virBitmapClearBit(f_mask, i));
+                }
+
+                if (a_type->nmasks <= cache) {
+                    if (VIR_EXPAND_N(a_type->masks, a_type->nmasks,
+                                     cache - a_type->nmasks + 1) < 0) {
+                        virBitmapFree(a_mask);
+                        goto cleanup;
+                    }
+                }
+                a_type->masks[cache] = a_mask;
+            }
+        }
+    }
+
+    ret = 0;
+ cleanup:
+    if (!save_ptr)
+        virObjectUnref(alloc_free);
+    return ret;
+}
+
+/* This checks if the directory for the alloc exists.  If not it tries to create
+ * it and apply appropriate alloc settings. */
+int
+virResctrlAllocCreate(virResctrlInfoPtr r_info,
+                      virResctrlAllocPtr alloc,
+                      const char *drivername,
+                      const char *machinename)
+{
+    char *alloc_path = NULL;
+    char *schemata_path = NULL;
+    bool dir_created = false;
+    char *alloc_str = NULL;
+    int ret = -1;
+    int lockfd = -1;
+
+    if (!alloc)
+        return 0;
+
+    if (!alloc->path &&
+        virAsprintf(&alloc->path, "%s/%s-%s-%s",
+                    SYSFS_RESCTRL_PATH, drivername, machinename, alloc->id) < 0)
+        return -1;
+
+    /* Check if this allocation was already created */
+    if (virFileIsDir(alloc->path)) {
+        VIR_FREE(alloc_path);
+        return 0;
+    }
+
+    if (virFileExists(alloc->path)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Path '%s' for resctrl allocation exists and is not
a "
+                         "directory"), alloc->path);
+        goto cleanup;
+    }
+
+    lockfd = virResctrlLockWrite();
+    if (lockfd < 0)
+        goto cleanup;
+
+    if (virResctrlAllocMasksAssign(r_info, alloc, NULL) < 0)
+        goto cleanup;
+
+    alloc_str = virResctrlAllocFormat(alloc);
+    if (!alloc_str)
+        return -1;
+
+    if (virAsprintf(&schemata_path, "%s/schemata", alloc->path) < 0)
+        goto cleanup;
+
+    if (virFileMakePath(alloc->path) < 0) {
+        virReportSystemError(errno,
+                             _("Cannot create resctrl directory
'%s'"),
+                             alloc->path);
+        goto cleanup;
+    }
+    dir_created = true;
+
+    if (virFileWriteStr(schemata_path, alloc_str, 0) < 0) {
+        virReportSystemError(errno,
+                             _("Cannot write into schemata file
'%s'"),
+                             schemata_path);
+        goto cleanup;
+    }
+
+    ret = 0;
+ cleanup:
+    if (ret < 0 && dir_created)
+        rmdir(alloc->path);
+    virResctrlUnlock(lockfd);
+    VIR_FREE(alloc_str);
+    VIR_FREE(alloc_path);
+    VIR_FREE(schemata_path);
+    return ret;
+}
+
+int
+virResctrlAllocAddPID(virResctrlAllocPtr alloc,
+                      pid_t pid)
+{
+    char *tasks = NULL;
+    char *pidstr = NULL;
+    int ret = 0;
+
+    if (!alloc->path) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Cannot add pid to non-existing resctrl
allocation"));
+        return -1;
+    }
+
+    if (virAsprintf(&tasks, "%s/tasks", alloc->path) < 0)
+        return -1;
+
+    if (virAsprintf(&pidstr, "%lld", (long long int) pid) < 0)
+        goto cleanup;
+
+    if (virFileWriteStr(tasks, pidstr, 0) < 0) {
+        virReportSystemError(errno,
+                             _("Cannot write pid in tasks file '%s'"),
+                             tasks);
+        goto cleanup;
+    }
+
+    ret = 0;
+ cleanup:
+    VIR_FREE(tasks);
+    VIR_FREE(pidstr);
+    return ret;
+}
+
+int
+virResctrlAllocRemove(virResctrlAllocPtr alloc)
+{
+    int ret = 0;
+
+    if (!alloc->path)
+        return 0;
+
+    VIR_DEBUG("Removing resctrl allocation %s", alloc->path);
+    if (rmdir(alloc->path) != 0 && errno != ENOENT) {
+        ret = -errno;
+        VIR_ERROR(_("Unable to remove %s (%d)"), alloc->path, errno);
+    }
+
+    return ret;
+}
diff --git a/src/util/virresctrl.h b/src/util/virresctrl.h
index c4df88f23c3a..b233eca41c03 100644
--- a/src/util/virresctrl.h
+++ b/src/util/virresctrl.h
@@ -62,4 +62,63 @@ virResctrlInfoGetCache(virResctrlInfoPtr resctrl,
                        size_t *ncontrols,
                        virResctrlInfoPerCachePtr **controls);
 
+/* Alloc-related things */
+typedef struct _virResctrlAlloc virResctrlAlloc;
+typedef virResctrlAlloc *virResctrlAllocPtr;
+
+typedef int virResctrlAllocForeachSizeCallback(unsigned int level,
+                                               virCacheType type,
+                                               unsigned int cache,
+                                               unsigned long long size,
+                                               void *opaque);
+
+virResctrlAllocPtr
+virResctrlAllocNewFromInfo(virResctrlInfoPtr info);
+
+int
+virResctrlAllocUpdateSize(virResctrlAllocPtr *resctrl,
+                          unsigned int level,
+                          virCacheType type,
+                          unsigned int cache,
+                          unsigned long long size);
+
+int
+virResctrlAllocUpdateMask(virResctrlAllocPtr *resctrl,
+                          unsigned int level,
+                          virCacheType type,
+                          unsigned int cache,
+                          virBitmapPtr mask);
+
+int
+virResctrlAllocSetSize(virResctrlAllocPtr *resctrl,
+                       unsigned int level,
+                       virCacheType type,
+                       unsigned int cache,
+                       unsigned long long size);
+
+int
+virResctrlAllocForeachSize(virResctrlAllocPtr resctrl,
+                           virResctrlAllocForeachSizeCallback cb,
+                           void *opaque);
+
+int
+virResctrlAllocSetID(virResctrlAllocPtr alloc,
+                     const char *id);
+
+char *
+virResctrlAllocFormat(virResctrlAllocPtr alloc);
+
+int
+virResctrlAllocCreate(virResctrlInfoPtr r_info,
+                      virResctrlAllocPtr alloc,
+                      const char *drivername,
+                      const char *machinename);
+
+int
+virResctrlAllocAddPID(virResctrlAllocPtr alloc,
+                      pid_t pid);
+
+int
+virResctrlAllocRemove(virResctrlAllocPtr alloc);
+
 #endif /*  __VIR_RESCTRL_H__ */
diff --git a/src/util/virresctrlpriv.h b/src/util/virresctrlpriv.h
new file mode 100644
index 000000000000..4255ad496302
--- /dev/null
+++ b/src/util/virresctrlpriv.h
@@ -0,0 +1,32 @@
+/*
+ * virresctrlpriv.h:
+ *
+ * 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, see
+ * <http://www.gnu.org/licenses/>;.
+ */
+
+#ifndef __VIR_RESCTRL_PRIV_H__
+# define __VIR_RESCTRL_PRIV_H__
+
+# include "virresctrl.h"
+
+virResctrlAllocPtr
+virResctrlAllocGetFree(virResctrlInfoPtr resctrl);
+
+int
+virResctrlAllocMasksAssign(virResctrlInfoPtr r_info,
+                           virResctrlAllocPtr alloc,
+                           void **save_ptr);
+
+#endif /* __VIR_RESCTRL_PRIV_H__ */
-- 
2.15.0


    

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[libvirt] [PATCH 16/21] resctrl: Add functions to work with resctrl allocations