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Date:      Mon, 10 Aug 2020 12:05:55 +0000 (UTC)
From:      Mateusz Guzik <mjg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r364079 - head/sys/kern
Message-ID:  <202008101205.07AC5tnP051980@repo.freebsd.org>
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Author: mjg
Date: Mon Aug 10 12:05:55 2020
New Revision: 364079
URL: https://svnweb.freebsd.org/changeset/base/364079

Log:
  cache: resize struct namecache to a multiply of alignment
  
  For example struct namecache on amd64 is 100 bytes, but it has to occupies
  104. Use the extra bytes to support longer names.

Modified:
  head/sys/kern/vfs_cache.c

Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c	Mon Aug 10 11:51:56 2020	(r364078)
+++ head/sys/kern/vfs_cache.c	Mon Aug 10 12:05:55 2020	(r364079)
@@ -159,7 +159,18 @@ struct	namecache_ts {
  * alignment for everyone. Note this is a nop for 64-bit platforms.
  */
 #define CACHE_ZONE_ALIGNMENT	UMA_ALIGNOF(time_t)
+#define	CACHE_PATH_CUTOFF	39
 
+#define CACHE_ZONE_SMALL_SIZE		(sizeof(struct namecache) + CACHE_PATH_CUTOFF + 1)
+#define CACHE_ZONE_SMALL_TS_SIZE	(sizeof(struct namecache_ts) + CACHE_PATH_CUTOFF + 1)
+#define CACHE_ZONE_LARGE_SIZE		(sizeof(struct namecache) + NAME_MAX + 1)
+#define CACHE_ZONE_LARGE_TS_SIZE	(sizeof(struct namecache_ts) + NAME_MAX + 1)
+
+_Static_assert((CACHE_ZONE_SMALL_SIZE % (CACHE_ZONE_ALIGNMENT + 1)) == 0, "bad zone size");
+_Static_assert((CACHE_ZONE_SMALL_TS_SIZE % (CACHE_ZONE_ALIGNMENT + 1)) == 0, "bad zone size");
+_Static_assert((CACHE_ZONE_LARGE_SIZE % (CACHE_ZONE_ALIGNMENT + 1)) == 0, "bad zone size");
+_Static_assert((CACHE_ZONE_LARGE_TS_SIZE % (CACHE_ZONE_ALIGNMENT + 1)) == 0, "bad zone size");
+
 #define	nc_vp		n_un.nu_vp
 #define	nc_neg		n_un.nu_neg
 
@@ -339,8 +350,6 @@ static uma_zone_t __read_mostly cache_zone_small_ts;
 static uma_zone_t __read_mostly cache_zone_large;
 static uma_zone_t __read_mostly cache_zone_large_ts;
 
-#define	CACHE_PATH_CUTOFF	35
-
 static struct namecache *
 cache_alloc(int len, int ts)
 {
@@ -2095,22 +2104,14 @@ nchinit(void *dummy __unused)
 {
 	u_int i;
 
-	cache_zone_small = uma_zcreate("S VFS Cache",
-	    sizeof(struct namecache) + CACHE_PATH_CUTOFF + 1,
-	    NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT,
-	    UMA_ZONE_ZINIT);
-	cache_zone_small_ts = uma_zcreate("STS VFS Cache",
-	    sizeof(struct namecache_ts) + CACHE_PATH_CUTOFF + 1,
-	    NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT,
-	    UMA_ZONE_ZINIT);
-	cache_zone_large = uma_zcreate("L VFS Cache",
-	    sizeof(struct namecache) + NAME_MAX + 1,
-	    NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT,
-	    UMA_ZONE_ZINIT);
-	cache_zone_large_ts = uma_zcreate("LTS VFS Cache",
-	    sizeof(struct namecache_ts) + NAME_MAX + 1,
-	    NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT,
-	    UMA_ZONE_ZINIT);
+	cache_zone_small = uma_zcreate("S VFS Cache", CACHE_ZONE_SMALL_SIZE,
+	    NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT, UMA_ZONE_ZINIT);
+	cache_zone_small_ts = uma_zcreate("STS VFS Cache", CACHE_ZONE_SMALL_TS_SIZE,
+	    NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT, UMA_ZONE_ZINIT);
+	cache_zone_large = uma_zcreate("L VFS Cache", CACHE_ZONE_LARGE_SIZE,
+	    NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT, UMA_ZONE_ZINIT);
+	cache_zone_large_ts = uma_zcreate("LTS VFS Cache", CACHE_ZONE_LARGE_TS_SIZE,
+	    NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT, UMA_ZONE_ZINIT);
 
 	VFS_SMR_ZONE_SET(cache_zone_small);
 	VFS_SMR_ZONE_SET(cache_zone_small_ts);

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