arch/tile: enhance existing finv_buffer_remote() routine

It now takes an additional argument so it can be used to
flush-and-invalidate pages that are cached using hash-for-home
as well those that are cached with coherence point on a single cpu.

This allows it to be used more widely for changing the coherence
point of arbitrary pages when necessary.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This commit is contained in:
Chris Metcalf 2011-02-28 15:48:39 -05:00
parent 3cebbafd28
commit 63b7ca6b04
4 changed files with 141 additions and 56 deletions

View File

@ -138,55 +138,12 @@ static inline void finv_buffer(void *buffer, size_t size)
}
/*
* Flush & invalidate a VA range that is homed remotely on a single core,
* waiting until the memory controller holds the flushed values.
* Flush and invalidate a VA range that is homed remotely, waiting
* until the memory controller holds the flushed values. If "hfh" is
* true, we will do a more expensive flush involving additional loads
* to make sure we have touched all the possible home cpus of a buffer
* that is homed with "hash for home".
*/
static inline void finv_buffer_remote(void *buffer, size_t size)
{
char *p;
int i;
/*
* Flush and invalidate the buffer out of the local L1/L2
* and request the home cache to flush and invalidate as well.
*/
__finv_buffer(buffer, size);
/*
* Wait for the home cache to acknowledge that it has processed
* all the flush-and-invalidate requests. This does not mean
* that the flushed data has reached the memory controller yet,
* but it does mean the home cache is processing the flushes.
*/
__insn_mf();
/*
* Issue a load to the last cache line, which can't complete
* until all the previously-issued flushes to the same memory
* controller have also completed. If we weren't striping
* memory, that one load would be sufficient, but since we may
* be, we also need to back up to the last load issued to
* another memory controller, which would be the point where
* we crossed an 8KB boundary (the granularity of striping
* across memory controllers). Keep backing up and doing this
* until we are before the beginning of the buffer, or have
* hit all the controllers.
*/
for (i = 0, p = (char *)buffer + size - 1;
i < (1 << CHIP_LOG_NUM_MSHIMS()) && p >= (char *)buffer;
++i) {
const unsigned long STRIPE_WIDTH = 8192;
/* Force a load instruction to issue. */
*(volatile char *)p;
/* Jump to end of previous stripe. */
p -= STRIPE_WIDTH;
p = (char *)((unsigned long)p | (STRIPE_WIDTH - 1));
}
/* Wait for the loads (and thus flushes) to have completed. */
__insn_mf();
}
void finv_buffer_remote(void *buffer, size_t size, int hfh);
#endif /* _ASM_TILE_CACHEFLUSH_H */

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@ -21,3 +21,105 @@ void __flush_icache_range(unsigned long start, unsigned long end)
{
invalidate_icache((const void *)start, end - start, PAGE_SIZE);
}
/* Force a load instruction to issue. */
static inline void force_load(char *p)
{
*(volatile char *)p;
}
/*
* Flush and invalidate a VA range that is homed remotely on a single
* core (if "!hfh") or homed via hash-for-home (if "hfh"), waiting
* until the memory controller holds the flushed values.
*/
void finv_buffer_remote(void *buffer, size_t size, int hfh)
{
char *p, *base;
size_t step_size, load_count;
const unsigned long STRIPE_WIDTH = 8192;
/*
* Flush and invalidate the buffer out of the local L1/L2
* and request the home cache to flush and invalidate as well.
*/
__finv_buffer(buffer, size);
/*
* Wait for the home cache to acknowledge that it has processed
* all the flush-and-invalidate requests. This does not mean
* that the flushed data has reached the memory controller yet,
* but it does mean the home cache is processing the flushes.
*/
__insn_mf();
/*
* Issue a load to the last cache line, which can't complete
* until all the previously-issued flushes to the same memory
* controller have also completed. If we weren't striping
* memory, that one load would be sufficient, but since we may
* be, we also need to back up to the last load issued to
* another memory controller, which would be the point where
* we crossed an 8KB boundary (the granularity of striping
* across memory controllers). Keep backing up and doing this
* until we are before the beginning of the buffer, or have
* hit all the controllers.
*
* If we are flushing a hash-for-home buffer, it's even worse.
* Each line may be homed on a different tile, and each tile
* may have up to four lines that are on different
* controllers. So as we walk backwards, we have to touch
* enough cache lines to satisfy these constraints. In
* practice this ends up being close enough to "load from
* every cache line on a full memory stripe on each
* controller" that we simply do that, to simplify the logic.
*
* FIXME: See bug 9535 for some issues with this code.
*/
if (hfh) {
step_size = L2_CACHE_BYTES;
load_count = (STRIPE_WIDTH / L2_CACHE_BYTES) *
(1 << CHIP_LOG_NUM_MSHIMS());
} else {
step_size = STRIPE_WIDTH;
load_count = (1 << CHIP_LOG_NUM_MSHIMS());
}
/* Load the last byte of the buffer. */
p = (char *)buffer + size - 1;
force_load(p);
/* Bump down to the end of the previous stripe or cache line. */
p -= step_size;
p = (char *)((unsigned long)p | (step_size - 1));
/* Figure out how far back we need to go. */
base = p - (step_size * (load_count - 2));
if ((long)base < (long)buffer)
base = buffer;
/*
* Fire all the loads we need. The MAF only has eight entries
* so we can have at most eight outstanding loads, so we
* unroll by that amount.
*/
#pragma unroll 8
for (; p >= base; p -= step_size)
force_load(p);
/*
* Repeat, but with inv's instead of loads, to get rid of the
* data we just loaded into our own cache and the old home L3.
* No need to unroll since inv's don't target a register.
*/
p = (char *)buffer + size - 1;
__insn_inv(p);
p -= step_size;
p = (char *)((unsigned long)p | (step_size - 1));
for (; p >= base; p -= step_size)
__insn_inv(p);
/* Wait for the load+inv's (and thus finvs) to have completed. */
__insn_mf();
}

View File

@ -179,23 +179,46 @@ void flush_remote(unsigned long cache_pfn, unsigned long cache_control,
panic("Unsafe to continue.");
}
void flush_remote_page(struct page *page, int order)
{
int i, pages = (1 << order);
for (i = 0; i < pages; ++i, ++page) {
void *p = kmap_atomic(page);
int hfh = 0;
int home = page_home(page);
#if CHIP_HAS_CBOX_HOME_MAP()
if (home == PAGE_HOME_HASH)
hfh = 1;
else
#endif
BUG_ON(home < 0 || home >= NR_CPUS);
finv_buffer_remote(p, PAGE_SIZE, hfh);
kunmap_atomic(p);
}
}
void homecache_evict(const struct cpumask *mask)
{
flush_remote(0, HV_FLUSH_EVICT_L2, mask, 0, 0, 0, NULL, NULL, 0);
}
/* Return a mask of the cpus whose caches currently own these pages. */
static void homecache_mask(struct page *page, int pages,
/*
* Return a mask of the cpus whose caches currently own these pages.
* The return value is whether the pages are all coherently cached
* (i.e. none are immutable, incoherent, or uncached).
*/
static int homecache_mask(struct page *page, int pages,
struct cpumask *home_mask)
{
int i;
int cached_coherently = 1;
cpumask_clear(home_mask);
for (i = 0; i < pages; ++i) {
int home = page_home(&page[i]);
if (home == PAGE_HOME_IMMUTABLE ||
home == PAGE_HOME_INCOHERENT) {
cpumask_copy(home_mask, cpu_possible_mask);
return;
return 0;
}
#if CHIP_HAS_CBOX_HOME_MAP()
if (home == PAGE_HOME_HASH) {
@ -203,11 +226,14 @@ static void homecache_mask(struct page *page, int pages,
continue;
}
#endif
if (home == PAGE_HOME_UNCACHED)
if (home == PAGE_HOME_UNCACHED) {
cached_coherently = 0;
continue;
}
BUG_ON(home < 0 || home >= NR_CPUS);
cpumask_set_cpu(home, home_mask);
}
return cached_coherently;
}
/*

View File

@ -1620,7 +1620,7 @@ static unsigned int tile_net_tx_frags(lepp_frag_t *frags,
if (b_len != 0) {
if (!hash_default)
finv_buffer_remote(b_data, b_len);
finv_buffer_remote(b_data, b_len, 0);
cpa = __pa(b_data);
frags[n].cpa_lo = cpa;
@ -1643,7 +1643,7 @@ static unsigned int tile_net_tx_frags(lepp_frag_t *frags,
if (!hash_default) {
void *va = pfn_to_kaddr(pfn) + f->page_offset;
BUG_ON(PageHighMem(f->page));
finv_buffer_remote(va, f->size);
finv_buffer_remote(va, f->size, 0);
}
cpa = ((phys_addr_t)pfn << PAGE_SHIFT) + f->page_offset;