From e2deee3ea6136b6189e8cfd26379420b9a398d96 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Tue, 2 Apr 2013 13:23:40 +0000 Subject: [PATCH 1/2] xen-mapcache: replace last_address_index with a last_entry pointer Replace last_address_index and last_address_vaddr with a single pointer to the last MapCacheEntry used. Signed-off-by: Stefano Stabellini --- xen-mapcache.c | 34 ++++++++++++++++------------------ 1 file changed, 16 insertions(+), 18 deletions(-) diff --git a/xen-mapcache.c b/xen-mapcache.c index dc6d1fadb7..a80cbdb6a7 100644 --- a/xen-mapcache.c +++ b/xen-mapcache.c @@ -74,8 +74,7 @@ typedef struct MapCache { QTAILQ_HEAD(map_cache_head, MapCacheRev) locked_entries; /* For most cases (>99.9%), the page address is the same. */ - hwaddr last_address_index; - uint8_t *last_address_vaddr; + MapCacheEntry *last_entry; unsigned long max_mcache_size; unsigned int mcache_bucket_shift; @@ -105,7 +104,6 @@ void xen_map_cache_init(phys_offset_to_gaddr_t f, void *opaque) mapcache->opaque = opaque; QTAILQ_INIT(&mapcache->locked_entries); - mapcache->last_address_index = -1; if (geteuid() == 0) { rlimit_as.rlim_cur = RLIM_INFINITY; @@ -210,9 +208,11 @@ tryagain: trace_xen_map_cache(phys_addr); - if (address_index == mapcache->last_address_index && !lock && !__size) { - trace_xen_map_cache_return(mapcache->last_address_vaddr + address_offset); - return mapcache->last_address_vaddr + address_offset; + if (mapcache->last_entry != NULL && + mapcache->last_entry->paddr_index == address_index && + !lock && !__size) { + trace_xen_map_cache_return(mapcache->last_entry->vaddr_base + address_offset); + return mapcache->last_entry->vaddr_base + address_offset; } /* size is always a multiple of MCACHE_BUCKET_SIZE */ @@ -249,7 +249,7 @@ tryagain: if(!test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT, entry->valid_mapping)) { - mapcache->last_address_index = -1; + mapcache->last_entry = NULL; if (!translated && mapcache->phys_offset_to_gaddr) { phys_addr = mapcache->phys_offset_to_gaddr(phys_addr, size, mapcache->opaque); translated = true; @@ -259,19 +259,18 @@ tryagain: return NULL; } - mapcache->last_address_index = address_index; - mapcache->last_address_vaddr = entry->vaddr_base; + mapcache->last_entry = entry; if (lock) { MapCacheRev *reventry = g_malloc0(sizeof(MapCacheRev)); entry->lock++; - reventry->vaddr_req = mapcache->last_address_vaddr + address_offset; - reventry->paddr_index = mapcache->last_address_index; + reventry->vaddr_req = mapcache->last_entry->vaddr_base + address_offset; + reventry->paddr_index = mapcache->last_entry->paddr_index; reventry->size = entry->size; QTAILQ_INSERT_HEAD(&mapcache->locked_entries, reventry, next); } - trace_xen_map_cache_return(mapcache->last_address_vaddr + address_offset); - return mapcache->last_address_vaddr + address_offset; + trace_xen_map_cache_return(mapcache->last_entry->vaddr_base + address_offset); + return mapcache->last_entry->vaddr_base + address_offset; } ram_addr_t xen_ram_addr_from_mapcache(void *ptr) @@ -338,9 +337,9 @@ void xen_invalidate_map_cache_entry(uint8_t *buffer) QTAILQ_REMOVE(&mapcache->locked_entries, reventry, next); g_free(reventry); - if (mapcache->last_address_index == paddr_index) { - mapcache->last_address_index = -1; - mapcache->last_address_vaddr = NULL; + if (mapcache->last_entry != NULL && + mapcache->last_entry->paddr_index == paddr_index) { + mapcache->last_entry = NULL; } entry = &mapcache->entry[paddr_index % mapcache->nr_buckets]; @@ -404,8 +403,7 @@ void xen_invalidate_map_cache(void) entry->valid_mapping = NULL; } - mapcache->last_address_index = -1; - mapcache->last_address_vaddr = NULL; + mapcache->last_entry = NULL; mapcache_unlock(); } From 044d4e1aae539bd4214175bd9591b3de7986cf18 Mon Sep 17 00:00:00 2001 From: Hanweidong Date: Tue, 2 Apr 2013 13:22:41 +0000 Subject: [PATCH 2/2] xen-mapcache: pass the right size argument to test_bits Compute the correct size for test_bits(). qemu_get_ram_ptr() and qemu_safe_ram_ptr() will call xen_map_cache() with size is 0 if the requested address is in the RAM. Then xen_map_cache() will pass the size 0 to test_bits() for checking if the corresponding pfn was mapped in cache. But test_bits() will always return 1 when size is 0 without any bit testing. Actually, for this case, test_bits should check one bit. So this patch introduced a __test_bit_size which is greater than 0 and a multiple of XC_PAGE_SIZE, then test_bits can work correctly with __test_bit_size >> XC_PAGE_SHIFT as its size. Signed-off-by: Zhenguo Wang Signed-off-by: Weidong Han Signed-off-by: Stefano Stabellini --- xen-mapcache.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/xen-mapcache.c b/xen-mapcache.c index a80cbdb6a7..5a626cdf84 100644 --- a/xen-mapcache.c +++ b/xen-mapcache.c @@ -200,6 +200,7 @@ uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size, hwaddr address_index; hwaddr address_offset; hwaddr __size = size; + hwaddr __test_bit_size = size; bool translated = false; tryagain: @@ -208,9 +209,23 @@ tryagain: trace_xen_map_cache(phys_addr); + /* __test_bit_size is always a multiple of XC_PAGE_SIZE */ + if (size) { + __test_bit_size = size + (phys_addr & (XC_PAGE_SIZE - 1)); + + if (__test_bit_size % XC_PAGE_SIZE) { + __test_bit_size += XC_PAGE_SIZE - (__test_bit_size % XC_PAGE_SIZE); + } + } else { + __test_bit_size = XC_PAGE_SIZE; + } + if (mapcache->last_entry != NULL && mapcache->last_entry->paddr_index == address_index && - !lock && !__size) { + !lock && !__size && + test_bits(address_offset >> XC_PAGE_SHIFT, + __test_bit_size >> XC_PAGE_SHIFT, + mapcache->last_entry->valid_mapping)) { trace_xen_map_cache_return(mapcache->last_entry->vaddr_base + address_offset); return mapcache->last_entry->vaddr_base + address_offset; } @@ -229,7 +244,8 @@ tryagain: while (entry && entry->lock && entry->vaddr_base && (entry->paddr_index != address_index || entry->size != __size || - !test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT, + !test_bits(address_offset >> XC_PAGE_SHIFT, + __test_bit_size >> XC_PAGE_SHIFT, entry->valid_mapping))) { pentry = entry; entry = entry->next; @@ -241,13 +257,15 @@ tryagain: } else if (!entry->lock) { if (!entry->vaddr_base || entry->paddr_index != address_index || entry->size != __size || - !test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT, + !test_bits(address_offset >> XC_PAGE_SHIFT, + __test_bit_size >> XC_PAGE_SHIFT, entry->valid_mapping)) { xen_remap_bucket(entry, __size, address_index); } } - if(!test_bits(address_offset >> XC_PAGE_SHIFT, size >> XC_PAGE_SHIFT, + if(!test_bits(address_offset >> XC_PAGE_SHIFT, + __test_bit_size >> XC_PAGE_SHIFT, entry->valid_mapping)) { mapcache->last_entry = NULL; if (!translated && mapcache->phys_offset_to_gaddr) {