chiark / gitweb /
journal: optimize iteration by skipping exhausted files
[elogind.git] / src / journal / sd-journal.c
index d171600eefa3596120f7e6b9c25ba518a7857a60..0aaf2257d4c668640a151f0b5de15b8ff7cbd8a4 100644 (file)
@@ -87,7 +87,7 @@ static void detach_location(sd_journal *j) {
         j->current_field = 0;
 
         ORDERED_HASHMAP_FOREACH(f, j->files, i)
-                f->current_offset = 0;
+                journal_file_reset_location(f);
 }
 
 static void reset_location(sd_journal *j) {
@@ -114,20 +114,19 @@ static void init_location(Location *l, LocationType type, JournalFile *f, Object
         l->seqnum_set = l->realtime_set = l->monotonic_set = l->xor_hash_set = true;
 }
 
-static void set_location(sd_journal *j, LocationType type, JournalFile *f, Object *o,
-                         direction_t direction, uint64_t offset) {
+static void set_location(sd_journal *j, JournalFile *f, Object *o) {
         assert(j);
-        assert(type == LOCATION_DISCRETE || type == LOCATION_SEEK);
         assert(f);
         assert(o);
 
-        init_location(&j->current_location, type, f, o);
+        init_location(&j->current_location, LOCATION_DISCRETE, f, o);
 
         j->current_file = f;
         j->current_field = 0;
 
-        f->last_direction = direction;
-        f->current_offset = offset;
+        /* Let f know its candidate entry was picked. */
+        assert(f->location_type == LOCATION_SEEK);
+        f->location_type = LOCATION_DISCRETE;
 }
 
 static int match_is_valid(const void *data, size_t size) {
@@ -413,90 +412,6 @@ _public_ void sd_journal_flush_matches(sd_journal *j) {
         detach_location(j);
 }
 
-static int compare_entry_order(JournalFile *af, Object *_ao,
-                               JournalFile *bf, uint64_t bp) {
-
-        uint64_t a, b;
-        Object *ao, *bo;
-        int r;
-
-        assert(af);
-        assert(bf);
-        assert(_ao);
-
-        /* The mmap cache might invalidate the object from the first
-         * file if we look at the one from the second file. Hence
-         * temporarily copy the header of the first one, and look at
-         * that only. */
-        ao = alloca(offsetof(EntryObject, items));
-        memcpy(ao, _ao, offsetof(EntryObject, items));
-
-        r = journal_file_move_to_object(bf, OBJECT_ENTRY, bp, &bo);
-        if (r < 0)
-                return strcmp(af->path, bf->path);
-
-        /* We operate on two different files here, hence we can access
-         * two objects at the same time, which we normally can't.
-         *
-         * If contents and timestamps match, these entries are
-         * identical, even if the seqnum does not match */
-
-        if (sd_id128_equal(ao->entry.boot_id, bo->entry.boot_id) &&
-            ao->entry.monotonic == bo->entry.monotonic &&
-            ao->entry.realtime == bo->entry.realtime &&
-            ao->entry.xor_hash == bo->entry.xor_hash)
-                return 0;
-
-        if (sd_id128_equal(af->header->seqnum_id, bf->header->seqnum_id)) {
-
-                /* If this is from the same seqnum source, compare
-                 * seqnums */
-                a = le64toh(ao->entry.seqnum);
-                b = le64toh(bo->entry.seqnum);
-
-                if (a < b)
-                        return -1;
-                if (a > b)
-                        return 1;
-
-                /* Wow! This is weird, different data but the same
-                 * seqnums? Something is borked, but let's make the
-                 * best of it and compare by time. */
-        }
-
-        if (sd_id128_equal(ao->entry.boot_id, bo->entry.boot_id)) {
-
-                /* If the boot id matches, compare monotonic time */
-                a = le64toh(ao->entry.monotonic);
-                b = le64toh(bo->entry.monotonic);
-
-                if (a < b)
-                        return -1;
-                if (a > b)
-                        return 1;
-        }
-
-        /* Otherwise, compare UTC time */
-        a = le64toh(ao->entry.realtime);
-        b = le64toh(bo->entry.realtime);
-
-        if (a < b)
-                return -1;
-        if (a > b)
-                return 1;
-
-        /* Finally, compare by contents */
-        a = le64toh(ao->entry.xor_hash);
-        b = le64toh(bo->entry.xor_hash);
-
-        if (a < b)
-                return -1;
-        if (a > b)
-                return 1;
-
-        return 0;
-}
-
 _pure_ static int compare_with_location(JournalFile *af, Object *ao, Location *l) {
         uint64_t a;
 
@@ -812,14 +727,20 @@ static int next_with_matches(
         return next_for_match(j, j->level0, f, direction == DIRECTION_DOWN ? cp+1 : cp-1, direction, ret, offset);
 }
 
-static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direction, Object **ret, uint64_t *offset) {
+static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direction) {
         Object *c;
-        uint64_t cp;
+        uint64_t cp, n_entries;
         int r;
 
         assert(j);
         assert(f);
 
+        /* If we hit EOF before, recheck if any new entries arrived. */
+        n_entries = le64toh(f->header->n_entries);
+        if (f->location_type == LOCATION_TAIL && n_entries == f->last_n_entries)
+                return 0;
+        f->last_n_entries = n_entries;
+
         if (f->last_direction == direction && f->current_offset > 0) {
                 cp = f->current_offset;
 
@@ -855,10 +776,7 @@ static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direc
                         found = true;
 
                 if (found) {
-                        if (ret)
-                                *ret = c;
-                        if (offset)
-                                *offset = cp;
+                        journal_file_save_location(f, direction, c, cp);
                         return 1;
                 }
 
@@ -870,8 +788,6 @@ static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direc
 
 static int real_journal_next(sd_journal *j, direction_t direction) {
         JournalFile *f, *new_file = NULL;
-        uint64_t new_offset = 0;
-        uint64_t p = 0;
         Iterator i;
         Object *o;
         int r;
@@ -882,38 +798,38 @@ static int real_journal_next(sd_journal *j, direction_t direction) {
         ORDERED_HASHMAP_FOREACH(f, j->files, i) {
                 bool found;
 
-                r = next_beyond_location(j, f, direction, &o, &p);
+                r = next_beyond_location(j, f, direction);
                 if (r < 0) {
                         log_debug_errno(r, "Can't iterate through %s, ignoring: %m", f->path);
                         remove_file_real(j, f);
                         continue;
-                } else if (r == 0)
+                } else if (r == 0) {
+                        f->location_type = LOCATION_TAIL;
                         continue;
+                }
 
                 if (!new_file)
                         found = true;
                 else {
                         int k;
 
-                        k = compare_entry_order(f, o, new_file, new_offset);
+                        k = journal_file_compare_locations(f, new_file);
 
                         found = direction == DIRECTION_DOWN ? k < 0 : k > 0;
                 }
 
-                if (found) {
+                if (found)
                         new_file = f;
-                        new_offset = p;
-                }
         }
 
         if (!new_file)
                 return 0;
 
-        r = journal_file_move_to_object(new_file, OBJECT_ENTRY, new_offset, &o);
+        r = journal_file_move_to_object(new_file, OBJECT_ENTRY, new_file->current_offset, &o);
         if (r < 0)
                 return r;
 
-        set_location(j, LOCATION_DISCRETE, new_file, o, direction, new_offset);
+        set_location(j, new_file, o);
 
         return 1;
 }
@@ -1410,7 +1326,7 @@ static int add_directory(sd_journal *j, const char *prefix, const char *dirname)
 
         d = opendir(path);
         if (!d) {
-                log_debug("Failed to open %s: %m", path);
+                log_debug_errno(errno, "Failed to open %s: %m", path);
                 if (errno == ENOENT)
                         return 0;
                 return -errno;
@@ -1456,7 +1372,7 @@ static int add_directory(sd_journal *j, const char *prefix, const char *dirname)
                 de = readdir(d);
                 if (!de && errno != 0) {
                         r = -errno;
-                        log_debug("Failed to read directory %s: %m", m->path);
+                        log_debug_errno(errno, "Failed to read directory %s: %m", m->path);
                         return r;
                 }
                 if (!de)
@@ -1546,7 +1462,7 @@ static int add_root_directory(sd_journal *j, const char *p) {
                 de = readdir(d);
                 if (!de && errno != 0) {
                         r = -errno;
-                        log_debug("Failed to read directory %s: %m", m->path);
+                        log_debug_errno(errno, "Failed to read directory %s: %m", m->path);
                         return r;
                 }
                 if (!de)
@@ -2273,7 +2189,6 @@ static int determine_change(sd_journal *j) {
 }
 
 _public_ int sd_journal_process(sd_journal *j) {
-        uint8_t buffer[sizeof(struct inotify_event) + FILENAME_MAX] _alignas_(struct inotify_event);
         bool got_something = false;
 
         assert_return(j, -EINVAL);
@@ -2282,6 +2197,7 @@ _public_ int sd_journal_process(sd_journal *j) {
         j->last_process_usec = now(CLOCK_MONOTONIC);
 
         for (;;) {
+                uint8_t buffer[INOTIFY_EVENT_MAX] _alignas_(struct inotify_event);
                 struct inotify_event *e;
                 ssize_t l;
 
@@ -2295,18 +2211,8 @@ _public_ int sd_journal_process(sd_journal *j) {
 
                 got_something = true;
 
-                e = (struct inotify_event*) buffer;
-                while (l > 0) {
-                        size_t step;
-
+                FOREACH_INOTIFY_EVENT(e, buffer, l)
                         process_inotify_event(j, e);
-
-                        step = sizeof(struct inotify_event) + e->len;
-                        assert(step <= (size_t) l);
-
-                        e = (struct inotify_event*) ((uint8_t*) e + step);
-                        l -= step;
-                }
         }
 }
 
@@ -2526,7 +2432,6 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_
                 size_t ol;
                 bool found;
                 int r;
-                void *release_cookie;
 
                 /* Proceed to next data object in the field's linked list */
                 if (j->unique_offset == 0) {
@@ -2552,10 +2457,10 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_
                         continue;
                 }
 
-                /* We do not use the type context here, but 0 instead,
-                 * so that we can look at this data object at the same
+                /* We do not use OBJECT_DATA context here, but OBJECT_UNUSED
+                 * instead, so that we can look at this data object at the same
                  * time as one on another file */
-                r = journal_file_move_to_object(j->unique_file, 0, j->unique_offset, &o);
+                r = journal_file_move_to_object(j->unique_file, OBJECT_UNUSED, j->unique_offset, &o);
                 if (r < 0)
                         return r;
 
@@ -2567,10 +2472,6 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_
                         return -EBADMSG;
                 }
 
-                r = journal_file_object_keep(j->unique_file, o, j->unique_offset, &release_cookie);
-                if (r < 0)
-                        return r;
-
                 r = return_data(j, j->unique_file, o, &odata, &ol);
                 if (r < 0)
                         return r;
@@ -2615,10 +2516,6 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_
                                 found = true;
                 }
 
-                r = journal_file_object_release(j->unique_file, release_cookie);
-                if (r < 0)
-                        return r;
-
                 if (found)
                         continue;