zfs: use zero_region instead of allocating a dedicated page

This commit is contained in:
Mateusz Guzik 2022-03-29 11:05:56 +00:00
parent 05621e0b20
commit 40c911e8da

View File

@ -113,7 +113,6 @@ static kstat_t *abd_ksp;
* memory by only using a single zero buffer for the scatter chunks.
*/
abd_t *abd_zero_scatter = NULL;
static char *abd_zero_buf = NULL;
static uint_t
abd_chunkcnt_for_bytes(size_t size)
@ -241,18 +240,16 @@ abd_free_struct_impl(abd_t *abd)
/*
* Allocate scatter ABD of size SPA_MAXBLOCKSIZE, where
* each chunk in the scatterlist will be set to abd_zero_buf.
* each chunk in the scatterlist will be set to the same area.
*/
_Static_assert(ZERO_REGION_SIZE >= PAGE_SIZE, "zero_region too small");
static void
abd_alloc_zero_scatter(void)
{
uint_t i, n;
n = abd_chunkcnt_for_bytes(SPA_MAXBLOCKSIZE);
abd_zero_buf = kmem_cache_alloc(abd_chunk_cache, KM_PUSHPAGE);
memset(abd_zero_buf, 0, PAGE_SIZE);
abd_zero_scatter = abd_alloc_struct(SPA_MAXBLOCKSIZE);
abd_zero_scatter->abd_flags |= ABD_FLAG_OWNER | ABD_FLAG_ZEROS;
abd_zero_scatter->abd_size = SPA_MAXBLOCKSIZE;
@ -260,7 +257,7 @@ abd_alloc_zero_scatter(void)
for (i = 0; i < n; i++) {
ABD_SCATTER(abd_zero_scatter).abd_chunks[i] =
abd_zero_buf;
__DECONST(void *, zero_region);
}
ABDSTAT_BUMP(abdstat_scatter_cnt);
@ -275,7 +272,6 @@ abd_free_zero_scatter(void)
abd_free_struct(abd_zero_scatter);
abd_zero_scatter = NULL;
kmem_cache_free(abd_chunk_cache, abd_zero_buf);
}
static int