KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 113 insertions, 0 deletions

diff --git a/scripts/bloat-o-meter b/scripts/bloat-o-meter
new file mode 100755
index 000000000..5868a8b11
--- /dev/null
+++ b/scripts/bloat-o-meter
@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+#
+# Copyright 2004 Matt Mackall <mpm@selenic.com>
+#
+# inspired by perl Bloat-O-Meter (c) 1997 by Andi Kleen
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+import sys, os, re, argparse
+from signal import signal, SIGPIPE, SIG_DFL
+
+signal(SIGPIPE, SIG_DFL)
+
+parser = argparse.ArgumentParser(description="Simple script used to compare the symbol sizes of 2 object files")
+group = parser.add_mutually_exclusive_group()
+group.add_argument('-c', help='categorize output based on symbol type', action='store_true')
+group.add_argument('-d', help='Show delta of Data Section', action='store_true')
+group.add_argument('-t', help='Show delta of text Section', action='store_true')
+parser.add_argument('-p', dest='prefix', help='Arch prefix for the tool being used. Useful in cross build scenarios')
+parser.add_argument('file_old', help='First file to compare')
+parser.add_argument('file_new', help='Second file to compare')
+
+args = parser.parse_args()
+
+re_NUMBER = re.compile(r'\.[0-9]+')
+
+def getsizes(file, format):
+    sym = {}
+    nm = "nm"
+    if args.prefix:
+        nm = "{}nm".format(args.prefix)
+
+    with os.popen("{} --size-sort {}".format(nm, file)) as f:
+        for line in f:
+            if line.startswith("\n") or ":" in line:
+                continue
+            size, type, name = line.split()
+            if type in format:
+                # strip generated symbols
+                if name.startswith("__mod_"): continue
+                if name.startswith("__se_sys"): continue
+                if name.startswith("__se_compat_sys"): continue
+                if name.startswith("__addressable_"): continue
+                if name.startswith("__noinstr_text_start"): continue
+                if name.startswith("_sdata"): continue
+                if name == "linux_banner": continue
+                if name == "vermagic": continue
+                # statics and some other optimizations adds random .NUMBER
+                name = re_NUMBER.sub('', name)
+                sym[name] = sym.get(name, 0) + int(size, 16)
+    return sym
+
+def calc(oldfile, newfile, format):
+    old = getsizes(oldfile, format)
+    new = getsizes(newfile, format)
+    grow, shrink, add, remove, up, down = 0, 0, 0, 0, 0, 0
+    delta, common = [], {}
+    otot, ntot = 0, 0
+
+    for a in old:
+        if a in new:
+            common[a] = 1
+
+    for name in old:
+        otot += old[name]
+        if name not in common:
+            remove += 1
+            down += old[name]
+            delta.append((-old[name], name))
+
+    for name in new:
+        ntot += new[name]
+        if name not in common:
+            add += 1
+            up += new[name]
+            delta.append((new[name], name))
+
+    for name in common:
+        d = new.get(name, 0) - old.get(name, 0)
+        if d>0: grow, up = grow+1, up+d
+        if d<0: shrink, down = shrink+1, down-d
+        delta.append((d, name))
+
+    delta.sort(reverse=True)
+    return grow, shrink, add, remove, up, down, delta, old, new, otot, ntot
+
+def print_result(symboltype, symbolformat):
+    grow, shrink, add, remove, up, down, delta, old, new, otot, ntot = \
+    calc(args.file_old, args.file_new, symbolformat)
+
+    print("add/remove: %s/%s grow/shrink: %s/%s up/down: %s/%s (%s)" % \
+          (add, remove, grow, shrink, up, -down, up-down))
+    print("%-40s %7s %7s %+7s" % (symboltype, "old", "new", "delta"))
+    for d, n in delta:
+        if d: print("%-40s %7s %7s %+7d" % (n, old.get(n,"-"), new.get(n,"-"), d))
+
+    if otot:
+        percent = (ntot - otot) * 100.0 / otot
+    else:
+        percent = 0
+    print("Total: Before=%d, After=%d, chg %+.2f%%" % (otot, ntot, percent))
+
+if args.c:
+    print_result("Function", "tTwW")
+    print_result("Data", "dDbBvV")
+    print_result("RO Data", "rR")
+elif args.d:
+    print_result("Data", "dDbBrRvV")
+elif args.t:
+    print_result("Function", "tTwW")
+else:
+    print_result("Function", "tTdDbBrRvVwW")