Re: [HPDD-discuss] [PATCH v2] Staging: lustre: llite: Use a mutex instead of spinlock

Perhaps I am confused or better versions of these primitives have made my understanding outmoded, but isn't it reasonable when a lock is expected to be held for a very short time to use a spin lock? Something like a single list manipulation seems like a great candidate for spinning instead of sleeping. At the least, mutexes are not always better than spinlocks, so a swap without a context specific explanation of why seems wrong. Thoughts from others? ________________________________________ From: HPDD-discuss [hpdd-discuss-bounces(a)lists.01.org] on behalf of Shraddha Barke [shraddha.6596(a)gmail.com] Sent: Thursday, August 06, 2015 2:37 PM To: Oleg Drokin; Andreas Dilger; Greg Kroah-Hartman; Al Viro; Tina Johnson; Joe Perches; HPDD-discuss(a)lists.01.org Cc: Shraddha Barke Subject: [HPDD-discuss] [PATCH v2] Staging: lustre: llite: Use a mutex instead of spinlock Using a mutex instead of a spinlock results in more flexibility ( i.e it allows to sleep while the lock is held). Signed-off-by: Shraddha Barke <shraddha.6596(a)gmail.com&gt; --- Changes in v2: -Replace DEFINE_SPINLOCK() with DEFINE_MUTEX drivers/staging/lustre/lustre/llite/llite_lib.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c index ab4839c..cd71eaa 100644 --- a/drivers/staging/lustre/lustre/llite/llite_lib.c +++ b/drivers/staging/lustre/lustre/llite/llite_lib.c @@ -61,7 +61,7 @@ struct dentry *llite_root; struct kset *llite_kset; static LIST_HEAD(ll_super_blocks); -static DEFINE_SPINLOCK(ll_sb_lock); +static DEFINE_MUTEX(ll_sb_lock); #ifndef log2 #define log2(n) ffz(~(n)) @@ -112,9 +112,9 @@ static struct ll_sb_info *ll_init_sbi(struct super_block *sb) class_uuid_unparse(uuid, &sbi->ll_sb_uuid); CDEBUG(D_CONFIG, "generated uuid: %s\n", sbi->ll_sb_uuid.uuid); - spin_lock(&ll_sb_lock); + mutex_lock(&ll_sb_lock); list_add_tail(&sbi->ll_list, &ll_super_blocks); - spin_unlock(&ll_sb_lock); + mutex_unlock(&ll_sb_lock); sbi->ll_flags |= LL_SBI_VERBOSE; sbi->ll_flags |= LL_SBI_CHECKSUM; @@ -145,9 +145,9 @@ static void ll_free_sbi(struct super_block *sb) struct ll_sb_info *sbi = ll_s2sbi(sb); if (sbi != NULL) { - spin_lock(&ll_sb_lock); + mutex_lock(&ll_sb_lock); list_del(&sbi->ll_list); - spin_unlock(&ll_sb_lock); + mutex_unlock(&ll_sb_lock); kfree(sbi); } } -- 2.1.0 _______________________________________________ HPDD-discuss mailing list HPDD-discuss(a)lists.01.org https://lists.01.org/mailman/listinfo/hpdd-discuss