From: Ronen Friedman <rfriedma@redhat.com>
Date: Thu, 4 Aug 2022 16:24:53 +0000 (+0000)
Subject: osd: faster versions of SnapMapper::get_legacy_prefix() & make_purged_snap_key()
X-Git-Tag: v18.0.0~311^2~1
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=2586468c8b818fdb1d4da26f862bc3f7701c4547;p=ceph.git

osd: faster versions of SnapMapper::get_legacy_prefix() & make_purged_snap_key()

Using fmtlib, and treating the size of uint64_t as a known
quantity.

Signed-off-by: Ronen Friedman <rfriedma@redhat.com>
---

diff --git a/src/osd/SnapMapper.cc b/src/osd/SnapMapper.cc
index 26ace62a7382e..9936808c10d2d 100644
--- a/src/osd/SnapMapper.cc
+++ b/src/osd/SnapMapper.cc
@@ -419,10 +419,10 @@ int SnapMapper::get_snaps(
 
 string SnapMapper::make_purged_snap_key(int64_t pool, snapid_t last)
 {
-  char k[80];
-  snprintf(k, sizeof(k), "%s_%llu_%016llx", PURGED_SNAP_PREFIX,
-	   (unsigned long long)pool, (unsigned long long)last);
-  return k;
+  return fmt::sprintf("%s_%lld_%016llx",
+		      PURGED_SNAP_PREFIX,
+		      pool,
+		      last);
 }
 
 void SnapMapper::make_purged_snap_key_value(
@@ -639,12 +639,9 @@ void SnapMapper::Scrubber::run()
 
 string SnapMapper::get_legacy_prefix(snapid_t snap)
 {
-  char buf[100];
-  int len = snprintf(
-    buf, sizeof(buf),
-    "%.*X_",
-    (int)(sizeof(snap)*2), static_cast<unsigned>(snap));
-  return LEGACY_MAPPING_PREFIX + string(buf, len);
+  return fmt::sprintf("%s%.16X_",
+		      LEGACY_MAPPING_PREFIX,
+		      snap);
 }
 
 string SnapMapper::to_legacy_raw_key(