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Message-Id: <20201207133024.16621-3-jgross@suse.com>
Date: Mon, 7 Dec 2020 14:30:24 +0100
From: Juergen Gross <jgross@...e.com>
To: xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Cc: Juergen Gross <jgross@...e.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Stefano Stabellini <sstabellini@...nel.org>
Subject: [PATCH 2/2] xen: don't use page->lru for ZONE_DEVICE memory
Commit 9e2369c06c8a18 ("xen: add helpers to allocate unpopulated
memory") introduced usage of ZONE_DEVICE memory for foreign memory
mappings.
Unfortunately this collides with using page->lru for Xen backend
private page caches.
Fix that by using page->zone_device_data instead.
Fixes: 9e2369c06c8a18 ("xen: add helpers to allocate unpopulated memory")
Signed-off-by: Juergen Gross <jgross@...e.com>
---
drivers/xen/grant-table.c | 65 +++++++++++++++++++++++++++++----
drivers/xen/unpopulated-alloc.c | 20 +++++-----
include/xen/grant_table.h | 4 ++
3 files changed, 73 insertions(+), 16 deletions(-)
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index e2e42912f241..696663a439fe 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -813,10 +813,63 @@ int gnttab_alloc_pages(int nr_pages, struct page **pages)
}
EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
+#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
+static inline void cache_init(struct gnttab_page_cache *cache)
+{
+ cache->pages = NULL;
+}
+
+static inline bool cache_empty(struct gnttab_page_cache *cache)
+{
+ return !cache->pages;
+}
+
+static inline struct page *cache_deq(struct gnttab_page_cache *cache)
+{
+ struct page *page;
+
+ page = cache->pages;
+ cache->pages = page->zone_device_data;
+
+ return page;
+}
+
+static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
+{
+ page->zone_device_data = cache->pages;
+ cache->pages = page;
+}
+#else
+static inline void cache_init(struct gnttab_page_cache *cache)
+{
+ INIT_LIST_HEAD(&cache->pages);
+}
+
+static inline bool cache_empty(struct gnttab_page_cache *cache)
+{
+ return list_empty(&cache->pages);
+}
+
+static inline struct page *cache_deq(struct gnttab_page_cache *cache)
+{
+ struct page *page;
+
+ page = list_first_entry(&cache->pages, struct page, lru);
+ list_del(&page[0]->lru);
+
+ return page;
+}
+
+static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)
+{
+ list_add(&page->lru, &cache->pages);
+}
+#endif
+
void gnttab_page_cache_init(struct gnttab_page_cache *cache)
{
spin_lock_init(&cache->lock);
- INIT_LIST_HEAD(&cache->pages);
+ cache_init(cache);
cache->num_pages = 0;
}
EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
@@ -827,13 +880,12 @@ int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page)
spin_lock_irqsave(&cache->lock, flags);
- if (list_empty(&cache->pages)) {
+ if (cache_empty(cache)) {
spin_unlock_irqrestore(&cache->lock, flags);
return gnttab_alloc_pages(1, page);
}
- page[0] = list_first_entry(&cache->pages, struct page, lru);
- list_del(&page[0]->lru);
+ page[0] = cache_deq(cache);
cache->num_pages--;
spin_unlock_irqrestore(&cache->lock, flags);
@@ -851,7 +903,7 @@ void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
spin_lock_irqsave(&cache->lock, flags);
for (i = 0; i < num; i++)
- list_add(&page[i]->lru, &cache->pages);
+ cache_enq(cache, page[i]);
cache->num_pages += num;
spin_unlock_irqrestore(&cache->lock, flags);
@@ -867,8 +919,7 @@ void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num)
spin_lock_irqsave(&cache->lock, flags);
while (cache->num_pages > num) {
- page[i] = list_first_entry(&cache->pages, struct page, lru);
- list_del(&page[i]->lru);
+ page[i] = cache_deq(cache);
cache->num_pages--;
if (++i == ARRAY_SIZE(page)) {
spin_unlock_irqrestore(&cache->lock, flags);
diff --git a/drivers/xen/unpopulated-alloc.c b/drivers/xen/unpopulated-alloc.c
index 8c512ea550bb..7762c1bb23cb 100644
--- a/drivers/xen/unpopulated-alloc.c
+++ b/drivers/xen/unpopulated-alloc.c
@@ -12,7 +12,7 @@
#include <xen/xen.h>
static DEFINE_MUTEX(list_lock);
-static LIST_HEAD(page_list);
+static struct page *page_list;
static unsigned int list_count;
static int fill_list(unsigned int nr_pages)
@@ -84,7 +84,8 @@ static int fill_list(unsigned int nr_pages)
struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i);
BUG_ON(!virt_addr_valid(vaddr + PAGE_SIZE * i));
- list_add(&pg->lru, &page_list);
+ pg->zone_device_data = page_list;
+ page_list = pg;
list_count++;
}
@@ -118,12 +119,10 @@ int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)
}
for (i = 0; i < nr_pages; i++) {
- struct page *pg = list_first_entry_or_null(&page_list,
- struct page,
- lru);
+ struct page *pg = page_list;
BUG_ON(!pg);
- list_del(&pg->lru);
+ page_list = pg->zone_device_data;
list_count--;
pages[i] = pg;
@@ -134,7 +133,8 @@ int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages)
unsigned int j;
for (j = 0; j <= i; j++) {
- list_add(&pages[j]->lru, &page_list);
+ pages[j]->zone_device_data = page_list;
+ page_list = pages[j];
list_count++;
}
goto out;
@@ -160,7 +160,8 @@ void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages)
mutex_lock(&list_lock);
for (i = 0; i < nr_pages; i++) {
- list_add(&pages[i]->lru, &page_list);
+ pages[i]->zone_device_data = page_list;
+ page_list = pages[i];
list_count++;
}
mutex_unlock(&list_lock);
@@ -189,7 +190,8 @@ static int __init init(void)
struct page *pg =
pfn_to_page(xen_extra_mem[i].start_pfn + j);
- list_add(&pg->lru, &page_list);
+ pg->zone_device_data = page_list;
+ page_list = pg;
list_count++;
}
}
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index c6ef8ffc1a09..b9c937b3a149 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -200,7 +200,11 @@ void gnttab_free_pages(int nr_pages, struct page **pages);
struct gnttab_page_cache {
spinlock_t lock;
+#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
+ struct page *pages;
+#else
struct list_head pages;
+#endif
unsigned int num_pages;
};
--
2.26.2
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