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zfs: lz4: add optional kmem_alloc support

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lz4 port from illumos to Linux added a 16KB per-CPU cache to accommodate for
the missing 16KB malloc. FreeBSD supports this size, making the extra cache
harmful as it can't share buckets.
This commit is contained in:
Mateusz Guzik 2020-11-05 03:25:23 +00:00
parent 3c50616fc1
commit aebc96831f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=367360
1 changed files with 57 additions and 4 deletions
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61
sys/contrib/openzfs/module/zfs/lz4.c
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@ -44,7 +44,8 @@ static int LZ4_compressCtx(void *ctx, const char *source, char *dest,
static int LZ4_compress64kCtx(void *ctx, const char *source, char *dest, static int LZ4_compress64kCtx(void *ctx, const char *source, char *dest,
int isize, int osize); int isize, int osize);
static kmem_cache_t *lz4_cache; static void *lz4_alloc(int flags);
static void lz4_free(void *ctx);
/*ARGSUSED*/ /*ARGSUSED*/
size_t size_t
@ -838,8 +839,7 @@ real_LZ4_compress(const char *source, char *dest, int isize, int osize)
void *ctx; void *ctx;
int result; int result;
ASSERT(lz4_cache != NULL); ctx = lz4_alloc(KM_SLEEP);
ctx = kmem_cache_alloc(lz4_cache, KM_SLEEP);
/* /*
* out of kernel memory, gently fall through - this will disable * out of kernel memory, gently fall through - this will disable
@ -855,7 +855,7 @@ real_LZ4_compress(const char *source, char *dest, int isize, int osize)
else else
result = LZ4_compressCtx(ctx, source, dest, isize, osize); result = LZ4_compressCtx(ctx, source, dest, isize, osize);
kmem_cache_free(lz4_cache, ctx); lz4_free(ctx);
return (result); return (result);
} }
@ -1014,6 +1014,23 @@ LZ4_uncompress_unknownOutputSize(const char *source, char *dest, int isize,
return (-1); return (-1);
} }
#ifdef __FreeBSD__
/*
* FreeBSD has 4, 8 and 16 KB malloc zones which can be used here.
* Should struct refTables get resized this may need to be revisited, hence
* compiler-time asserts.
*/
_Static_assert(sizeof(struct refTables) <= 16384,
"refTables too big for malloc");
_Static_assert((sizeof(struct refTables) % 4096) == 0,
"refTables not a multiple of page size");
#else
#define ZFS_LZ4_USE_CACHE
#endif
#ifdef ZFS_LZ4_USE_CACHE
static kmem_cache_t *lz4_cache;
void void
lz4_init(void) lz4_init(void)
{ {
@ -1029,3 +1046,39 @@ lz4_fini(void)
lz4_cache = NULL; lz4_cache = NULL;
} }
} }
static void *
lz4_alloc(int flags)
{
ASSERT(lz4_cache != NULL);
return (kmem_cache_alloc(lz4_cache, flags));
}
static void
lz4_free(void *ctx)
{
kmem_cache_free(lz4_cache, ctx);
}
#else
void
lz4_init(void)
{
}
void
lz4_fini(void)
{
}
static void *
lz4_alloc(int flags)
{
return (kmem_alloc(sizeof (struct refTables), flags));
}
static void
lz4_free(void *ctx)
{
kmem_free(ctx, sizeof (struct refTables));
}
#endif