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authorVenki Pallipadi <venkatesh.pallipadi@intel.com>2008-08-19 19:28:01 -0400
committerIngo Molnar <mingo@elte.hu>2008-08-20 06:08:37 -0400
commit80c5e73d6028e0f03ab0c70e7c4cbf98ac2e0c43 (patch)
treeb1ae13cc96dd94e7090942e5602df6277a4126e4
parentc6744955d0ec0cb485c28c51eeb7185e260f6172 (diff)
x86: fix Xorg startup/shutdown slowdown with PAT
Rene Herman reported significant Xorg startup/shutdown slowdown due to PAT. It turns out that the memtype list has thousands of entries. Add cached_entry to list add routine, in order to speed up the lookup for sequential reserve_memtype calls. Reported-by: Rene Herman <rene.herman@keyaccess.nl> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/mm/pat.c33
1 files changed, 31 insertions, 2 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 2fe30916d4b6..bb6e8a267bfe 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -207,6 +207,9 @@ static int chk_conflict(struct memtype *new, struct memtype *entry,
207 return -EBUSY; 207 return -EBUSY;
208} 208}
209 209
210static struct memtype *cached_entry;
211static u64 cached_start;
212
210/* 213/*
211 * req_type typically has one of the: 214 * req_type typically has one of the:
212 * - _PAGE_CACHE_WB 215 * - _PAGE_CACHE_WB
@@ -280,11 +283,17 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
280 283
281 spin_lock(&memtype_lock); 284 spin_lock(&memtype_lock);
282 285
286 if (cached_entry && start >= cached_start)
287 entry = cached_entry;
288 else
289 entry = list_entry(&memtype_list, struct memtype, nd);
290
283 /* Search for existing mapping that overlaps the current range */ 291 /* Search for existing mapping that overlaps the current range */
284 where = NULL; 292 where = NULL;
285 list_for_each_entry(entry, &memtype_list, nd) { 293 list_for_each_entry_continue(entry, &memtype_list, nd) {
286 if (end <= entry->start) { 294 if (end <= entry->start) {
287 where = entry->nd.prev; 295 where = entry->nd.prev;
296 cached_entry = list_entry(where, struct memtype, nd);
288 break; 297 break;
289 } else if (start <= entry->start) { /* end > entry->start */ 298 } else if (start <= entry->start) { /* end > entry->start */
290 err = chk_conflict(new, entry, new_type); 299 err = chk_conflict(new, entry, new_type);
@@ -292,6 +301,8 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
292 dprintk("Overlap at 0x%Lx-0x%Lx\n", 301 dprintk("Overlap at 0x%Lx-0x%Lx\n",
293 entry->start, entry->end); 302 entry->start, entry->end);
294 where = entry->nd.prev; 303 where = entry->nd.prev;
304 cached_entry = list_entry(where,
305 struct memtype, nd);
295 } 306 }
296 break; 307 break;
297 } else if (start < entry->end) { /* start > entry->start */ 308 } else if (start < entry->end) { /* start > entry->start */
@@ -299,7 +310,20 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
299 if (!err) { 310 if (!err) {
300 dprintk("Overlap at 0x%Lx-0x%Lx\n", 311 dprintk("Overlap at 0x%Lx-0x%Lx\n",
301 entry->start, entry->end); 312 entry->start, entry->end);
302 where = &entry->nd; 313 cached_entry = list_entry(entry->nd.prev,
314 struct memtype, nd);
315
316 /*
317 * Move to right position in the linked
318 * list to add this new entry
319 */
320 list_for_each_entry_continue(entry,
321 &memtype_list, nd) {
322 if (start <= entry->start) {
323 where = entry->nd.prev;
324 break;
325 }
326 }
303 } 327 }
304 break; 328 break;
305 } 329 }
@@ -314,6 +338,8 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
314 return err; 338 return err;
315 } 339 }
316 340
341 cached_start = start;
342
317 if (where) 343 if (where)
318 list_add(&new->nd, where); 344 list_add(&new->nd, where);
319 else 345 else
@@ -343,6 +369,9 @@ int free_memtype(u64 start, u64 end)
343 spin_lock(&memtype_lock); 369 spin_lock(&memtype_lock);
344 list_for_each_entry(entry, &memtype_list, nd) { 370 list_for_each_entry(entry, &memtype_list, nd) {
345 if (entry->start == start && entry->end == end) { 371 if (entry->start == start && entry->end == end) {
372 if (cached_entry == entry || cached_start == start)
373 cached_entry = NULL;
374
346 list_del(&entry->nd); 375 list_del(&entry->nd);
347 kfree(entry); 376 kfree(entry);
348 err = 0; 377 err = 0;