From: Gao Xiang <hsiangkao@redhat.com> To: linux-erofs@lists.ozlabs.org Cc: LKML <linux-kernel@vger.kernel.org>, Chao Yu <yuchao0@huawei.com>, Chao Yu <chao@kernel.org>, Gao Xiang <hsiangkao@redhat.com> Subject: [PATCH v2 3/3] erofs: simplify try_to_claim_pcluster() Date: Mon, 7 Dec 2020 09:23:46 +0800 [thread overview] Message-ID: <20201207012346.2713857-3-hsiangkao@redhat.com> (raw) In-Reply-To: <20201207012346.2713857-1-hsiangkao@redhat.com> simplify try_to_claim_pcluster() by directly using cmpxchg() here (the retry loop caused more overhead.) Also, move the chain loop detection in and rename it to z_erofs_try_to_claim_pcluster(). Signed-off-by: Gao Xiang <hsiangkao@redhat.com> --- fs/erofs/zdata.c | 51 +++++++++++++++++++++++------------------------- 1 file changed, 24 insertions(+), 27 deletions(-) diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index edd7325570e1..b1b6cd03046f 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -298,34 +298,33 @@ static int z_erofs_attach_page(struct z_erofs_collector *clt, return ret ? 0 : -EAGAIN; } -static enum z_erofs_collectmode -try_to_claim_pcluster(struct z_erofs_pcluster *pcl, - z_erofs_next_pcluster_t *owned_head) +static void z_erofs_try_to_claim_pcluster(struct z_erofs_collector *clt) { - /* let's claim these following types of pclusters */ -retry: - if (pcl->next == Z_EROFS_PCLUSTER_NIL) { - /* type 1, nil pcluster */ - if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL, - *owned_head) != Z_EROFS_PCLUSTER_NIL) - goto retry; + struct z_erofs_pcluster *pcl = clt->pcl; + z_erofs_next_pcluster_t *owned_head = &clt->owned_head; + /* type 1, nil pcluster (this pcluster doesn't belong to any chain.) */ + if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL, + *owned_head) == Z_EROFS_PCLUSTER_NIL) { *owned_head = &pcl->next; - /* lucky, I am the followee :) */ - return COLLECT_PRIMARY_FOLLOWED; - } else if (pcl->next == Z_EROFS_PCLUSTER_TAIL) { - /* - * type 2, link to the end of a existing open chain, - * be careful that its submission itself is governed - * by the original owned chain. - */ - if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL, - *owned_head) != Z_EROFS_PCLUSTER_TAIL) - goto retry; + /* so we can attach this pcluster to our submission chain. */ + clt->mode = COLLECT_PRIMARY_FOLLOWED; + return; + } + + /* + * type 2, link to the end of an existing open chain, be careful + * that its submission is controlled by the original attached chain. + */ + if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL, + *owned_head) == Z_EROFS_PCLUSTER_TAIL) { *owned_head = Z_EROFS_PCLUSTER_TAIL; - return COLLECT_PRIMARY_HOOKED; + clt->mode = COLLECT_PRIMARY_HOOKED; + clt->tailpcl = NULL; + return; } - return COLLECT_PRIMARY; /* :( better luck next time */ + /* type 3, it belongs to a chain, but it isn't the end of the chain */ + clt->mode = COLLECT_PRIMARY; } static int z_erofs_lookup_collection(struct z_erofs_collector *clt, @@ -370,10 +369,8 @@ static int z_erofs_lookup_collection(struct z_erofs_collector *clt, /* used to check tail merging loop due to corrupted images */ if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL) clt->tailpcl = pcl; - clt->mode = try_to_claim_pcluster(pcl, &clt->owned_head); - /* clean tailpcl if the current owned_head is Z_EROFS_PCLUSTER_TAIL */ - if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL) - clt->tailpcl = NULL; + + z_erofs_try_to_claim_pcluster(clt); clt->cl = cl; return 0; } -- 2.18.4
WARNING: multiple messages have this Message-ID (diff)
From: Gao Xiang <hsiangkao@redhat.com> To: linux-erofs@lists.ozlabs.org Cc: LKML <linux-kernel@vger.kernel.org> Subject: [PATCH v2 3/3] erofs: simplify try_to_claim_pcluster() Date: Mon, 7 Dec 2020 09:23:46 +0800 [thread overview] Message-ID: <20201207012346.2713857-3-hsiangkao@redhat.com> (raw) In-Reply-To: <20201207012346.2713857-1-hsiangkao@redhat.com> simplify try_to_claim_pcluster() by directly using cmpxchg() here (the retry loop caused more overhead.) Also, move the chain loop detection in and rename it to z_erofs_try_to_claim_pcluster(). Signed-off-by: Gao Xiang <hsiangkao@redhat.com> --- fs/erofs/zdata.c | 51 +++++++++++++++++++++++------------------------- 1 file changed, 24 insertions(+), 27 deletions(-) diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index edd7325570e1..b1b6cd03046f 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -298,34 +298,33 @@ static int z_erofs_attach_page(struct z_erofs_collector *clt, return ret ? 0 : -EAGAIN; } -static enum z_erofs_collectmode -try_to_claim_pcluster(struct z_erofs_pcluster *pcl, - z_erofs_next_pcluster_t *owned_head) +static void z_erofs_try_to_claim_pcluster(struct z_erofs_collector *clt) { - /* let's claim these following types of pclusters */ -retry: - if (pcl->next == Z_EROFS_PCLUSTER_NIL) { - /* type 1, nil pcluster */ - if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL, - *owned_head) != Z_EROFS_PCLUSTER_NIL) - goto retry; + struct z_erofs_pcluster *pcl = clt->pcl; + z_erofs_next_pcluster_t *owned_head = &clt->owned_head; + /* type 1, nil pcluster (this pcluster doesn't belong to any chain.) */ + if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL, + *owned_head) == Z_EROFS_PCLUSTER_NIL) { *owned_head = &pcl->next; - /* lucky, I am the followee :) */ - return COLLECT_PRIMARY_FOLLOWED; - } else if (pcl->next == Z_EROFS_PCLUSTER_TAIL) { - /* - * type 2, link to the end of a existing open chain, - * be careful that its submission itself is governed - * by the original owned chain. - */ - if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL, - *owned_head) != Z_EROFS_PCLUSTER_TAIL) - goto retry; + /* so we can attach this pcluster to our submission chain. */ + clt->mode = COLLECT_PRIMARY_FOLLOWED; + return; + } + + /* + * type 2, link to the end of an existing open chain, be careful + * that its submission is controlled by the original attached chain. + */ + if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL, + *owned_head) == Z_EROFS_PCLUSTER_TAIL) { *owned_head = Z_EROFS_PCLUSTER_TAIL; - return COLLECT_PRIMARY_HOOKED; + clt->mode = COLLECT_PRIMARY_HOOKED; + clt->tailpcl = NULL; + return; } - return COLLECT_PRIMARY; /* :( better luck next time */ + /* type 3, it belongs to a chain, but it isn't the end of the chain */ + clt->mode = COLLECT_PRIMARY; } static int z_erofs_lookup_collection(struct z_erofs_collector *clt, @@ -370,10 +369,8 @@ static int z_erofs_lookup_collection(struct z_erofs_collector *clt, /* used to check tail merging loop due to corrupted images */ if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL) clt->tailpcl = pcl; - clt->mode = try_to_claim_pcluster(pcl, &clt->owned_head); - /* clean tailpcl if the current owned_head is Z_EROFS_PCLUSTER_TAIL */ - if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL) - clt->tailpcl = NULL; + + z_erofs_try_to_claim_pcluster(clt); clt->cl = cl; return 0; } -- 2.18.4
next prev parent reply other threads:[~2020-12-07 1:26 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-12-07 1:23 [PATCH v2 1/3] erofs: get rid of magical Z_EROFS_MAPPING_STAGING Gao Xiang 2020-12-07 1:23 ` Gao Xiang 2020-12-07 1:23 ` [PATCH v2 2/3] erofs: insert to managed cache after adding to pcl Gao Xiang 2020-12-07 1:23 ` Gao Xiang 2020-12-08 8:51 ` Chao Yu 2020-12-08 8:51 ` Chao Yu 2020-12-07 1:23 ` Gao Xiang [this message] 2020-12-07 1:23 ` [PATCH v2 3/3] erofs: simplify try_to_claim_pcluster() Gao Xiang 2020-12-08 9:26 ` Chao Yu 2020-12-08 9:26 ` Chao Yu 2020-12-08 3:14 ` [PATCH v2 1/3] erofs: get rid of magical Z_EROFS_MAPPING_STAGING Gao Xiang 2020-12-08 3:14 ` Gao Xiang 2020-12-08 8:15 ` Chao Yu 2020-12-08 8:15 ` Chao Yu 2020-12-08 8:23 ` Gao Xiang 2020-12-08 8:23 ` Gao Xiang 2020-12-08 8:44 ` Chao Yu 2020-12-08 8:44 ` Chao Yu 2020-12-08 8:49 ` Gao Xiang 2020-12-08 8:49 ` Gao Xiang 2020-12-08 8:28 ` Gao Xiang 2020-12-08 8:28 ` Gao Xiang
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