[PATCH] kexec,x86: code optimization and adjustment for add_memmap and delete_memmap
Zhang Yanfei
zhangyanfei at cn.fujitsu.com
Mon Feb 25 07:38:41 EST 2013
The code in the two functions seems a little messy, So I modify
some of them, trying to make the logic more clearly.
For example,
code before:
for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
mstart = memmap_p[i].start;
mend = memmap_p[i].end;
if (mstart == 0 && mend == 0)
break;
for we already have nr_entries for this memmap_p array, so we needn't
have a check in every loop to see if we have go through the whole array.
code after:
for (i = 0; i < nr_entries; i++) {
mstart = memmap_p[i].start;
mend = memmap_p[i].end;
Signed-off-by: Zhang Yanfei <zhangyanfei at cn.fujitsu.com>
---
kexec/arch/i386/crashdump-x86.c | 93 ++++++++++++++++++---------------------
1 files changed, 43 insertions(+), 50 deletions(-)
diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
index 245402c..63f6b2b 100644
--- a/kexec/arch/i386/crashdump-x86.c
+++ b/kexec/arch/i386/crashdump-x86.c
@@ -518,21 +518,22 @@ static int exclude_region(int *nr_ranges, uint64_t start, uint64_t end)
/* Adds a segment from list of memory regions which new kernel can use to
* boot. Segment start and end should be aligned to 1K boundary. */
-static int add_memmap(struct memory_range *memmap_p, unsigned long long addr,
- size_t size)
+static int add_memmap(struct memory_range *memmap_p,
+ unsigned long long addr,
+ size_t size)
{
int i, j, nr_entries = 0, tidx = 0, align = 1024;
unsigned long long mstart, mend;
/* Do alignment check. */
- if ((addr%align) || (size%align))
+ if ((addr % align) || (size % align))
return -1;
/* Make sure at least one entry in list is free. */
- for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
+ for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
mstart = memmap_p[i].start;
mend = memmap_p[i].end;
- if (!mstart && !mend)
+ if (!mstart && !mend)
break;
else
nr_entries++;
@@ -540,31 +541,29 @@ static int add_memmap(struct memory_range *memmap_p, unsigned long long addr,
if (nr_entries == CRASH_MAX_MEMMAP_NR)
return -1;
- for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
+ for (i = 0; i < nr_entries; i++) {
mstart = memmap_p[i].start;
mend = memmap_p[i].end;
- if (mstart == 0 && mend == 0)
- break;
- if (mstart <= (addr+size-1) && mend >=addr)
+
+ if (mstart <= (addr + size - 1) && mend >= addr)
/* Overlapping region. */
return -1;
else if (addr > mend)
- tidx = i+1;
+ tidx = i + 1;
}
- /* Insert the memory region. */
- for (j = nr_entries-1; j >= tidx; j--)
- memmap_p[j+1] = memmap_p[j];
- memmap_p[tidx].start = addr;
- memmap_p[tidx].end = addr + size - 1;
+
+ /* Insert the memory region. */
+ for (j = nr_entries - 1; j >= tidx; j--)
+ memmap_p[j+1] = memmap_p[j];
+ memmap_p[tidx].start = addr;
+ memmap_p[tidx].end = addr + size - 1;
+ nr_entries++;
dbgprintf("Memmap after adding segment\n");
- for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
+ for (i = 0; i < nr_entries; i++) {
mstart = memmap_p[i].start;
mend = memmap_p[i].end;
- if (mstart == 0 && mend == 0)
- break;
- dbgprintf("%016llx - %016llx\n",
- mstart, mend);
+ dbgprintf("%016llx - %016llx\n", mstart, mend);
}
return 0;
@@ -572,19 +571,20 @@ static int add_memmap(struct memory_range *memmap_p, unsigned long long addr,
/* Removes a segment from list of memory regions which new kernel can use to
* boot. Segment start and end should be aligned to 1K boundary. */
-static int delete_memmap(struct memory_range *memmap_p, unsigned long long addr,
- size_t size)
+static int delete_memmap(struct memory_range *memmap_p,
+ unsigned long long addr,
+ size_t size)
{
int i, j, nr_entries = 0, tidx = -1, operation = 0, align = 1024;
unsigned long long mstart, mend;
struct memory_range temp_region;
/* Do alignment check. */
- if ((addr%align) || (size%align))
+ if ((addr % align) || (size % align))
return -1;
/* Make sure at least one entry in list is free. */
- for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
+ for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
mstart = memmap_p[i].start;
mend = memmap_p[i].end;
if (!mstart && !mend)
@@ -596,20 +596,16 @@ static int delete_memmap(struct memory_range *memmap_p, unsigned long long addr,
/* List if full */
return -1;
- for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
+ for (i = 0; i < nr_entries; i++) {
mstart = memmap_p[i].start;
mend = memmap_p[i].end;
- if (mstart == 0 && mend == 0)
- /* Did not find the segment in the list. */
- return -1;
+
if (mstart <= addr && mend >= (addr + size - 1)) {
if (mstart == addr && mend == (addr + size - 1)) {
/* Exact match. Delete region */
operation = -1;
tidx = i;
- break;
- }
- if (mstart != addr && mend != (addr + size - 1)) {
+ } else if (mstart != addr && mend != (addr + size - 1)) {
/* Split in two */
memmap_p[i].end = addr - 1;
temp_region.start = addr + size;
@@ -617,41 +613,38 @@ static int delete_memmap(struct memory_range *memmap_p, unsigned long long addr,
temp_region.type = memmap_p[i].type;
operation = 1;
tidx = i;
- break;
- }
-
- /* No addition/deletion required. Adjust the existing.*/
- if (mstart != addr) {
- memmap_p[i].end = addr - 1;
- break;
} else {
- memmap_p[i].start = addr + size;
- break;
+ /* No addition/deletion required. Adjust the existing.*/
+ if (mstart != addr)
+ memmap_p[i].end = addr - 1;
+ else
+ memmap_p[i].start = addr + size;
}
+ break;
}
}
- if ((operation == 1) && tidx >=0) {
+
+ if (operation == 1 && tidx >= 0) {
/* Insert the split memory region. */
- for (j = nr_entries-1; j > tidx; j--)
+ for (j = nr_entries - 1; j > tidx; j--)
memmap_p[j+1] = memmap_p[j];
memmap_p[tidx+1] = temp_region;
+ nr_entries++;
}
- if ((operation == -1) && tidx >=0) {
+
+ if (operation == -1 && tidx >= 0) {
/* Delete the exact match memory region. */
- for (j = i+1; j < CRASH_MAX_MEMMAP_NR; j++)
+ for (j = i + 1; j < nr_entries; j++)
memmap_p[j-1] = memmap_p[j];
memmap_p[j-1].start = memmap_p[j-1].end = 0;
+ nr_entries--;
}
dbgprintf("Memmap after deleting segment\n");
- for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
+ for (i = 0; i < nr_entries; i++) {
mstart = memmap_p[i].start;
mend = memmap_p[i].end;
- if (mstart == 0 && mend == 0) {
- break;
- }
- dbgprintf("%016llx - %016llx\n",
- mstart, mend);
+ dbgprintf("%016llx - %016llx\n", mstart, mend);
}
return 0;
--
1.7.1
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