Ignore mask ignores essential bits WHICH could have been contiguous.
This commit aims to rectify that
Cc: sta...@dpdk.org
Signed-off-by: Vipin P R <vip...@vmware.com>
Acked-by: Kumara Parameshwaran <kparamesh...@vmware.com>
---
Depends-on: 0001-Memory-Allocation-Fixes-ms_idx-jump-lookahead-during.patch
Depends-on: 0002-Memory-Allocation-Fixes-ms_idx-jump-lookbehind-durin.patch
---
lib/eal/common/eal_common_fbarray.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/lib/eal/common/eal_common_fbarray.c
b/lib/eal/common/eal_common_fbarray.c
index 313681a..29fffb6 100644
--- a/lib/eal/common/eal_common_fbarray.c
+++ b/lib/eal/common/eal_common_fbarray.c
@@ -138,7 +138,7 @@ find_next_n(const struct rte_fbarray *arr, unsigned int
start, unsigned int n,
last_msk = ~(UINT64_MAX << last_mod);
for (msk_idx = first; msk_idx < msk->n_masks; msk_idx++) {
- uint64_t cur_msk, lookahead_msk;
+ uint64_t cur_msk, lookahead_msk, lookahead_msk_;
unsigned int run_start, clz, left;
bool found = false;
/*
@@ -215,12 +215,14 @@ find_next_n(const struct rte_fbarray *arr, unsigned int
start, unsigned int n,
for (lookahead_idx = msk_idx + 1; lookahead_idx < msk->n_masks;
lookahead_idx++) {
- unsigned int s_idx, need;
+ unsigned int s_idx, need, fsb_idx, fcb_idx, ignore_bits;
lookahead_msk = msk->data[lookahead_idx];
/* if we're looking for free space, invert the mask */
if (!used)
lookahead_msk = ~lookahead_msk;
+
+ lookahead_msk_ = lookahead_msk;
/* figure out how many consecutive bits we need here */
need = RTE_MIN(left, MASK_ALIGN);
@@ -236,10 +238,23 @@ find_next_n(const struct rte_fbarray *arr, unsigned int
start, unsigned int n,
* as well, so skip that on next iteration.
*/
if (!lookahead_msk) {
- /* There aren't "need" number of
contiguous bits anywhere in the mask.
+ /* There aren't "need" number of
contiguous bits anywhere in the mask.
* Ignore these many number of bits
from LSB for the next iteration.
*/
ignore_msk = ~((1ULL << need) - 1);
+ } else {
+ /* Find the first clear bit */
+ fcb_idx =
__builtin_ffsll((~lookahead_msk_));
+ /* clear all bits upto the first clear
bit in lookahead_msk_. */
+ lookahead_msk_ = lookahead_msk_ &
((~0ULL) << fcb_idx);
+ /* find the first set bit in the
modified mask */
+ fsb_idx =
__builtin_ffsll(lookahead_msk_);
+ /* number of bits to ignore from the
next iteration */
+ ignore_bits = fsb_idx - 1;
+ /* ignore all bits preceding the first
set bit after the first clear bit
+ * starting from LSB of lookahead_msk_.
+ */
+ ignore_msk = ~((1ULL << ignore_bits) -
1);
}
msk_idx = lookahead_idx - 1;
break;
--
2.7.4
