[Xen-devel] [PATCH 3/4] tmem: drop unnecessary lock in tmem_relinquish_pages()

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

From: Bob Liu <bob.liu@xxxxxxxxxx>

CID 1150562

tmem_rwlock is unnecessary in tmem_relinquish_pages(), as
such lock is used as gate for hypercalls. However
tmem_relinquish_pages deals with pages that are no longer
owned by any domain - hence there is no need for tmem_rwlock.

Also the function is protected by the 'heap_lock' which
is the only calleer of this function.

This patch drops said lock.

Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 xen/common/tmem.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/xen/common/tmem.c b/xen/common/tmem.c
index f7f828f..f2dc26e 100644
--- a/xen/common/tmem.c
+++ b/xen/common/tmem.c
@@ -2794,9 +2794,6 @@ void *tmem_relinquish_pages(unsigned int order, unsigned 
int memflags)
         return NULL;
     }
 
-    if ( memflags & MEMF_tmem )
-        read_lock(&tmem_rwlock);
-
     while ( (pfp = tmem_page_list_get()) == NULL )
     {
         if ( (max_evictions-- <= 0) || !tmem_evict())
@@ -2812,9 +2809,6 @@ void *tmem_relinquish_pages(unsigned int order, unsigned 
int memflags)
         relinq_pgs++;
     }
 
-    if ( memflags & MEMF_tmem )
-        read_unlock(&tmem_rwlock);
-
     return pfp;
 }
 
-- 
1.8.5.3


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