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bh=xl16RQ27IbssBeTxi2z23S4vpV8WJZdQC/pP649MYjo=; b=gbUgGS0lYulxZj8dttigI2cBcbm7X/zCqixcE0Ng47fGYZ8JJQtM4yKoCtWLAEij6UMSAV EF5BN7WgzhP6ku72adczoeSx9u0G6yd1Dmz6f1lE68ohxf3A5DPWXggqTL7x0agAidANd0 oyTBhQHURt68TI1ey/TyZuR9H6SPEXQ= X-MC-Unique: zw5qGrT8MPGuOR0wh5cT5Q-1 From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Cc: Kevin Wolf , Hanna Reitz , Paolo Bonzini , John Snow , Vladimir Sementsov-Ogievskiy , Markus Armbruster , Stefan Hajnoczi , qemu-devel@nongnu.org, Emanuele Giuseppe Esposito Subject: [PATCH v2 03/11] bdrv_change_aio_context: use hash table instead of list of visited nodes Date: Mon, 25 Jul 2022 08:21:12 -0400 Message-Id: <20220725122120.309236-4-eesposit@redhat.com> In-Reply-To: <20220725122120.309236-1-eesposit@redhat.com> References: <20220725122120.309236-1-eesposit@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658751857820100001 Content-Type: text/plain; charset="utf-8" Minor performance improvement, but given that we have hash tables available, avoid iterating in the visited nodes list every time just to check if a node has been already visited. The data structure is not actually a proper hash map, but an hash set, as we are just adding nodes and not key,value pairs. Suggested-by: Hanna Reitz Signed-off-by: Emanuele Giuseppe Esposito Reviewed-by: Kevin Wolf --- block.c | 28 ++++++++++++++++------------ include/block/block-global-state.h | 2 +- include/block/block_int-common.h | 3 ++- 3 files changed, 19 insertions(+), 14 deletions(-) diff --git a/block.c b/block.c index c80e49009a..c02a628336 100644 --- a/block.c +++ b/block.c @@ -109,7 +109,7 @@ static void bdrv_reopen_abort(BDRVReopenState *reopen_s= tate); static bool bdrv_backing_overridden(BlockDriverState *bs); =20 static bool bdrv_change_aio_context(BlockDriverState *bs, AioContext *ctx, - GSList **visited, Transaction *tran, + GHashTable *visited, Transaction *tran, Error **errp); =20 /* If non-zero, use only whitelisted block drivers */ @@ -7444,14 +7444,15 @@ typedef struct BdrvStateSetAioContext { } BdrvStateSetAioContext; =20 static bool bdrv_parent_change_aio_context(BdrvChild *c, AioContext *ctx, - GSList **visited, Transaction *= tran, + GHashTable *visited, + Transaction *tran, Error **errp) { GLOBAL_STATE_CODE(); - if (g_slist_find(*visited, c)) { + if (g_hash_table_contains(visited, c)) { return true; } - *visited =3D g_slist_prepend(*visited, c); + g_hash_table_add(visited, c); =20 /* * A BdrvChildClass that doesn't handle AioContext changes cannot @@ -7482,14 +7483,14 @@ bool bdrv_child_can_set_aio_context(BdrvChild *c, A= ioContext *ctx, } =20 bool bdrv_child_change_aio_context(BdrvChild *c, AioContext *ctx, - GSList **visited, Transaction *tran, + GHashTable *visited, Transaction *tran, Error **errp) { GLOBAL_STATE_CODE(); - if (g_slist_find(*visited, c)) { + if (g_hash_table_contains(visited, c)) { return true; } - *visited =3D g_slist_prepend(*visited, c); + g_hash_table_add(visited, c); return bdrv_change_aio_context(c->bs, ctx, visited, tran, errp); } =20 @@ -7561,7 +7562,7 @@ static TransactionActionDrv set_aio_context =3D { * responsible for freeing the list afterwards. */ static bool bdrv_change_aio_context(BlockDriverState *bs, AioContext *ctx, - GSList **visited, Transaction *tran, + GHashTable *visited, Transaction *tran, Error **errp) { BdrvChild *c; @@ -7646,16 +7647,19 @@ int bdrv_child_try_change_aio_context(BlockDriverSt= ate *bs, AioContext *ctx, BdrvChild *ignore_child, Error **err= p) { Transaction *tran; - GSList *visited; + GHashTable *visited; int ret; AioContext *old_context =3D bdrv_get_aio_context(bs); GLOBAL_STATE_CODE(); =20 /* Recursion phase: go through all nodes of the graph */ tran =3D tran_new(); - visited =3D ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL; - ret =3D bdrv_change_aio_context(bs, ctx, &visited, tran, errp); - g_slist_free(visited); + visited =3D g_hash_table_new(NULL, NULL); + if (ignore_child) { + g_hash_table_add(visited, ignore_child); + } + ret =3D bdrv_change_aio_context(bs, ctx, visited, tran, errp); + g_hash_table_destroy(visited); =20 /* Linear phase: go through all callbacks collected in the transaction= */ =20 diff --git a/include/block/block-global-state.h b/include/block/block-globa= l-state.h index fdcb81a175..ceecf0aa8e 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -230,7 +230,7 @@ bool bdrv_can_set_aio_context(BlockDriverState *bs, Aio= Context *ctx, AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c); =20 bool bdrv_child_change_aio_context(BdrvChild *c, AioContext *ctx, - GSList **visited, Transaction *tran, + GHashTable *visited, Transaction *tran, Error **errp); int bdrv_child_try_change_aio_context(BlockDriverState *bs, AioContext *ct= x, BdrvChild *ignore_child, Error **err= p); diff --git a/include/block/block_int-common.h b/include/block/block_int-com= mon.h index 43828cf74f..c639873487 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -897,7 +897,8 @@ struct BdrvChildClass { void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore= ); =20 bool (*change_aio_ctx)(BdrvChild *child, AioContext *ctx, - GSList **visited, Transaction *tran, Error **er= rp); + GHashTable *visited, Transaction *tran, + Error **errp); =20 AioContext *(*get_parent_aio_context)(BdrvChild *child); =20 --=20 2.31.1