Le 07/03/2018 à 00:12, Nicholas Piggin a écrit :
On Tue, 6 Mar 2018 15:41:00 +0100
Christophe LEROY <christophe.le...@c-s.fr> wrote:
Le 06/03/2018 à 14:25, Nicholas Piggin a écrit :
+static bool slice_check_range_fits(struct mm_struct *mm,
+ const struct slice_mask *available,
+ unsigned long start, unsigned long len)
{
- DECLARE_BITMAP(result, SLICE_NUM_HIGH);
- /*
- * Make sure we just do bit compare only to the max
- * addr limit and not the full bit map size.
- */
- unsigned long slice_count =
GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit);
+ unsigned long end = start + len - 1;
+ u64 low_slices = 0;
- if (!SLICE_NUM_HIGH)
- return (mask->low_slices & available->low_slices) ==
- mask->low_slices;
+ if (start < SLICE_LOW_TOP) {
+ unsigned long mend = min(end, (SLICE_LOW_TOP - 1));
See slice_range_to_mask()
You'll have an issue here with PPC32, you have to cast (SLICE_LOW_TOP -
1) to unsigned long because SLICE_LOW_TOP is unsigned long long on PPC32
Okay thanks. Forgot to cross compiled it on 8xx, so I'll do that next
time.
+
+ low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
+ - (1u << GET_LOW_SLICE_INDEX(start));
+ }
+ if ((low_slices & available->low_slices) != low_slices)
+ return false;
+
+ if (SLICE_NUM_HIGH && ((start + len) > SLICE_LOW_TOP)) {
+ unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
+ unsigned long align_end = ALIGN(end, (1UL << SLICE_HIGH_SHIFT));
+ unsigned long count = GET_HIGH_SLICE_INDEX(align_end) -
start_index;
+ unsigned long i;
- bitmap_and(result, mask->high_slices,
- available->high_slices, slice_count);
+ for (i = start_index; i < start_index + count; i++) {
+ if (!test_bit(i, available->high_slices))
+ return false;
+ }
What about using bitmap_find_next_zero_area()
I'll look at it. Perhaps in another patch, because existing
loops are not using bitmap range operations either. A series
to convert those is a good idea.
@@ -562,15 +571,11 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
#endif
/* First check hint if it's valid or if we have MAP_FIXED */
- if (addr != 0 || fixed) {
- /* Build a mask for the requested range */
- slice_range_to_mask(addr, len, &mask);
- slice_print_mask(" mask", &mask);
-
+ if (addr || fixed) {
It is cleanup, should it really be part of this patch ?
@@ -596,10 +601,11 @@ unsigned long slice_get_unmapped_area(unsigned long addr,
unsigned long len,
slice_or_mask(&potential_mask, &good_mask);
slice_print_mask(" potential", &potential_mask);
- if ((addr != 0 || fixed) &&
- slice_check_fit(mm, &mask, &potential_mask)) {
- slice_dbg(" fits potential !\n");
- goto convert;
+ if (addr || fixed) {
+ if (slice_check_range_fits(mm, &potential_mask, addr, len)) {
+ slice_dbg(" fits potential !\n");
+ goto convert;
+ }
Why not keep the original structure and just replacing slice_check_fit()
by slice_check_range_fits() ?
I believe cleanups should not be mixed with real feature changes. If
needed, you should have a cleanup patch up front the serie.
For code that is already changing, I think minor cleanups are okay if
they're very simple. Maybe this is getting to the point of needing
another patch. You've made valid points for a lot of other unnecessary
cleanups though, so I'll fix all of those.
Ok, that's not a big point, but I like when patches really modifies
only the lines they need to modify. Why do we need a double if ?
Why not just the following ? With proper alignment of the second line
with the open parenthese, it fits in one line
if ((addr != 0 || fixed) &&
- slice_check_fit(mm, &mask, &potential_mask)) {
+ slice_check_range_fits(mm, &potential_mask, addr, len)) {
slice_dbg(" fits potential !\n");
goto convert;
}
Christophe
