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Szmigiero" Subject: Re: [RFC PATCH v2 4/9] migration/multifd: Make MultiFDPages_t:offset a flexible array member In-Reply-To: References: <20240722175914.24022-1-farosas@suse.de> <20240722175914.24022-5-farosas@suse.de> Date: Mon, 22 Jul 2024 17:36:56 -0300 Message-ID: <87ed7lyxhz.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Action: no action X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 5AF8021ADF X-Spamd-Result: default: False [-5.31 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; DWL_DNSWL_LOW(-1.00)[suse.de:dkim]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RCVD_VIA_SMTP_AUTH(0.00)[]; MISSING_XM_UA(0.00)[]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns,suse.de:dkim,suse.de:email]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DKIM_TRACE(0.00)[suse.de:+] Received-SPF: pass client-ip=2a07:de40:b251:101:10:150:64:1; envelope-from=farosas@suse.de; helo=smtp-out1.suse.de X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Peter Xu writes: > On Mon, Jul 22, 2024 at 02:59:09PM -0300, Fabiano Rosas wrote: >> We're about to use MultiFDPages_t from inside the MultiFDSendData >> payload union, which means we cannot have pointers to allocated data >> inside the pages structure, otherwise we'd lose the reference to that >> memory once another payload type touches the union. Move the offset >> array into the end of the structure and turn it into a flexible array >> member, so it is allocated along with the rest of MultiFDSendData in >> the next patches. >> >> Note that the ramblock pointer is still fine because the storage for >> it is not owned by the migration code. >> >> Signed-off-by: Fabiano Rosas >> --- >> migration/multifd.c | 21 ++++++--------------- >> migration/multifd.h | 4 ++-- >> 2 files changed, 8 insertions(+), 17 deletions(-) >> >> diff --git a/migration/multifd.c b/migration/multifd.c >> index 20a767157e..440319b361 100644 >> --- a/migration/multifd.c >> +++ b/migration/multifd.c >> @@ -389,22 +389,10 @@ static int multifd_recv_initial_packet(QIOChannel *c, Error **errp) >> return msg.id; >> } >> >> -static MultiFDPages_t *multifd_pages_init(uint32_t n) >> -{ >> - MultiFDPages_t *pages = g_new0(MultiFDPages_t, 1); >> - >> - pages->allocated = n; >> - pages->offset = g_new0(ram_addr_t, n); >> - >> - return pages; >> -} > > Considering this is the tricky object to allocate here, shall we keep the > function just for readability (and already dedups below two callers)? With > it, someone else will notice g_new0() stops working for MultiFDPages_t. > Some verbose comment would be nice too. > > Maybe we can also move multifd_ram_payload_size() from the next patch to > here. I guess so, I was trying to keep this diff small so it's easier to grasp. > >> - >> static void multifd_pages_clear(MultiFDPages_t *pages) >> { >> multifd_pages_reset(pages); >> pages->allocated = 0; >> - g_free(pages->offset); >> - pages->offset = NULL; >> g_free(pages); >> } >> >> @@ -1169,7 +1157,9 @@ bool multifd_send_setup(void) >> thread_count = migrate_multifd_channels(); >> multifd_send_state = g_malloc0(sizeof(*multifd_send_state)); >> multifd_send_state->params = g_new0(MultiFDSendParams, thread_count); >> - multifd_send_state->pages = multifd_pages_init(page_count); >> + multifd_send_state->pages = g_malloc0(sizeof(MultiFDPages_t) + >> + page_count * sizeof(ram_addr_t)); >> + multifd_send_state->pages->allocated = page_count; >> qemu_sem_init(&multifd_send_state->channels_created, 0); >> qemu_sem_init(&multifd_send_state->channels_ready, 0); >> qatomic_set(&multifd_send_state->exiting, 0); >> @@ -1181,8 +1171,9 @@ bool multifd_send_setup(void) >> qemu_sem_init(&p->sem, 0); >> qemu_sem_init(&p->sem_sync, 0); >> p->id = i; >> - p->pages = multifd_pages_init(page_count); >> - >> + p->pages = g_malloc0(sizeof(MultiFDPages_t) + >> + page_count * sizeof(ram_addr_t)); >> + p->pages->allocated = page_count; >> if (use_packets) { >> p->packet_len = sizeof(MultiFDPacket_t) >> + sizeof(uint64_t) * page_count; >> diff --git a/migration/multifd.h b/migration/multifd.h >> index c7b1ebe099..12d4247e23 100644 >> --- a/migration/multifd.h >> +++ b/migration/multifd.h >> @@ -78,9 +78,9 @@ typedef struct { >> uint32_t normal_num; >> /* number of allocated pages */ >> uint32_t allocated; >> + RAMBlock *block; >> /* offset of each page */ >> - ram_addr_t *offset; >> - RAMBlock *block; >> + ram_addr_t offset[]; >> } MultiFDPages_t; >> >> struct MultiFDRecvData { >> -- >> 2.35.3 >>