Very nice. The performance change can not be explained, but nice cleanup.
Reviewed by me
On Tue, 6 Sept 2022 at 11:31, Enzo Matsumiya <ematsumiya@xxxxxxx> wrote:
>
> Replace hardcoded alignment computations (e.g. (len + 7) & ~0x7) of
> (mostly) SMB2 messages length by ALIGN()/IS_ALIGNED() macros (right
> tools for the job, less prone to errors).
>
> But also replace (DIV_ROUND_UP(len, 8) * 8) with ALIGN(len, 8), which,
> if not optimized by the compiler, has the overhead of a multiplication
> and a division. Do the same for roundup() by replacing it by round_up()
> (division-less version, but requires the multiple to be a power of 2,
> which is always the case for us).
>
> Also remove some unecessary checks where !IS_ALIGNED() would fit, but
> calling round_up() directly is just fine as it'll be a no-op if the
> value is already aligned.
>
> Afraid this was a useless micro-optimization, I ran some tests with a
> very light workload, and I observed a ~50% perf improvement already:
>
> Record all cifs.ko functions:
> # trace-cmd record --module cifs -p function_graph
>
> (test-dir has ~50MB with ~4000 files)
> Test commands after share is mounted and with no activity:
> # cp -r test-dir /mnt/test
> # sync
> # umount /mnt/test
>
> Number of traced functions:
> # trace-cmd report -l | awk '{ print $6 }' | grep "^[0-9].*" | wc -l
> - unpatched: 307746
> - patched: 313199
>
> Measuring the average latency of all traced functions:
> # trace-cmd report -l | awk '{ print $6 }' | grep "^[0-9].*" | jq -s add/length
> - unpatched: 27105.577791262822 us
> - patched: 14548.665733635338 us
>
> So even though the patched version made 5k+ more function calls (for
> whatever reason), it still did it with ~50% reduced latency.
>
> On a larger scale, given the affected code paths, this patch should
> show a relevant improvement.
>
> Signed-off-by: Enzo Matsumiya <ematsumiya@xxxxxxx>
> ---
> Please let me know if my measurements are enough/valid.
>
> fs/cifs/cifssmb.c | 7 +++---
> fs/cifs/connect.c | 11 ++++++--
> fs/cifs/sess.c | 18 +++++--------
> fs/cifs/smb2inode.c | 4 +--
> fs/cifs/smb2misc.c | 2 +-
> fs/cifs/smb2pdu.c | 61 +++++++++++++++++++--------------------------
> 6 files changed, 47 insertions(+), 56 deletions(-)
>
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index 7aa91e272027..addf3fc62aef 100644
> --- a/fs/cifs/cifssmb.c
> +++ b/fs/cifs/cifssmb.c
> @@ -2305,7 +2305,7 @@ int CIFSSMBRenameOpenFile(const unsigned int xid, struct cifs_tcon *pTcon,
> remap);
> }
> rename_info->target_name_len = cpu_to_le32(2 * len_of_str);
> - count = 12 /* sizeof(struct set_file_rename) */ + (2 * len_of_str);
> + count = sizeof(struct set_file_rename) + (2 * len_of_str);
> byte_count += count;
> pSMB->DataCount = cpu_to_le16(count);
> pSMB->TotalDataCount = pSMB->DataCount;
> @@ -2796,7 +2796,7 @@ CIFSSMBQuerySymLink(const unsigned int xid, struct cifs_tcon *tcon,
> cifs_dbg(FYI, "Invalid return data count on get reparse info ioctl\n");
> goto qreparse_out;
> }
> - end_of_smb = 2 + get_bcc(&pSMBr->hdr) + (char *)&pSMBr->ByteCount;
> + end_of_smb = sizeof(__le16) + get_bcc(&pSMBr->hdr) + (char *)&pSMBr->ByteCount;
> reparse_buf = (struct reparse_symlink_data *)
> ((char *)&pSMBr->hdr.Protocol + data_offset);
> if ((char *)reparse_buf >= end_of_smb) {
> @@ -3350,8 +3350,7 @@ validate_ntransact(char *buf, char **ppparm, char **ppdata,
> pSMBr = (struct smb_com_ntransact_rsp *)buf;
>
> bcc = get_bcc(&pSMBr->hdr);
> - end_of_smb = 2 /* sizeof byte count */ + bcc +
> - (char *)&pSMBr->ByteCount;
> + end_of_smb = sizeof(__le16) + bcc + (char *)&pSMBr->ByteCount;
>
> data_offset = le32_to_cpu(pSMBr->DataOffset);
> data_count = le32_to_cpu(pSMBr->DataCount);
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index a0a06b6f252b..389127e21563 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -2833,9 +2833,12 @@ ip_rfc1001_connect(struct TCP_Server_Info *server)
> * sessinit is sent but no second negprot
> */
> struct rfc1002_session_packet *ses_init_buf;
> + unsigned int req_noscope_len;
> struct smb_hdr *smb_buf;
> +
> ses_init_buf = kzalloc(sizeof(struct rfc1002_session_packet),
> GFP_KERNEL);
> +
> if (ses_init_buf) {
> ses_init_buf->trailer.session_req.called_len = 32;
>
> @@ -2871,8 +2874,12 @@ ip_rfc1001_connect(struct TCP_Server_Info *server)
> ses_init_buf->trailer.session_req.scope2 = 0;
> smb_buf = (struct smb_hdr *)ses_init_buf;
>
> - /* sizeof RFC1002_SESSION_REQUEST with no scope */
> - smb_buf->smb_buf_length = cpu_to_be32(0x81000044);
> + /* sizeof RFC1002_SESSION_REQUEST with no scopes */
> + req_noscope_len = sizeof(struct rfc1002_session_packet) - 2;
> +
> + /* == cpu_to_be32(0x81000044) */
> + smb_buf->smb_buf_length =
> + cpu_to_be32((RFC1002_SESSION_REQUEST << 24) | req_noscope_len);
> rc = smb_send(server, smb_buf, 0x44);
> kfree(ses_init_buf);
> /*
> diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
> index 3af3b05b6c74..951874928d70 100644
> --- a/fs/cifs/sess.c
> +++ b/fs/cifs/sess.c
> @@ -601,11 +601,6 @@ static void unicode_ssetup_strings(char **pbcc_area, struct cifs_ses *ses,
> /* BB FIXME add check that strings total less
> than 335 or will need to send them as arrays */
>
> - /* unicode strings, must be word aligned before the call */
> -/* if ((long) bcc_ptr % 2) {
> - *bcc_ptr = 0;
> - bcc_ptr++;
> - } */
> /* copy user */
> if (ses->user_name == NULL) {
> /* null user mount */
> @@ -1318,7 +1313,7 @@ sess_auth_ntlmv2(struct sess_data *sess_data)
> }
>
> if (ses->capabilities & CAP_UNICODE) {
> - if (sess_data->iov[0].iov_len % 2) {
> + if (!IS_ALIGNED(sess_data->iov[0].iov_len, 2)) {
> *bcc_ptr = 0;
> bcc_ptr++;
> }
> @@ -1358,7 +1353,7 @@ sess_auth_ntlmv2(struct sess_data *sess_data)
> /* no string area to decode, do nothing */
> } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
> /* unicode string area must be word-aligned */
> - if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
> + if (!IS_ALIGNED((unsigned long)bcc_ptr - (unsigned long)smb_buf, 2)) {
> ++bcc_ptr;
> --bytes_remaining;
> }
> @@ -1442,8 +1437,7 @@ sess_auth_kerberos(struct sess_data *sess_data)
>
> if (ses->capabilities & CAP_UNICODE) {
> /* unicode strings must be word aligned */
> - if ((sess_data->iov[0].iov_len
> - + sess_data->iov[1].iov_len) % 2) {
> + if (!IS_ALIGNED(sess_data->iov[0].iov_len + sess_data->iov[1].iov_len, 2)) {
> *bcc_ptr = 0;
> bcc_ptr++;
> }
> @@ -1494,7 +1488,7 @@ sess_auth_kerberos(struct sess_data *sess_data)
> /* no string area to decode, do nothing */
> } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
> /* unicode string area must be word-aligned */
> - if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
> + if (!IS_ALIGNED((unsigned long)bcc_ptr - (unsigned long)smb_buf, 2)) {
> ++bcc_ptr;
> --bytes_remaining;
> }
> @@ -1546,7 +1540,7 @@ _sess_auth_rawntlmssp_assemble_req(struct sess_data *sess_data)
>
> bcc_ptr = sess_data->iov[2].iov_base;
> /* unicode strings must be word aligned */
> - if ((sess_data->iov[0].iov_len + sess_data->iov[1].iov_len) % 2) {
> + if (!IS_ALIGNED(sess_data->iov[0].iov_len + sess_data->iov[1].iov_len, 2)) {
> *bcc_ptr = 0;
> bcc_ptr++;
> }
> @@ -1747,7 +1741,7 @@ sess_auth_rawntlmssp_authenticate(struct sess_data *sess_data)
> /* no string area to decode, do nothing */
> } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
> /* unicode string area must be word-aligned */
> - if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
> + if (!IS_ALIGNED((unsigned long)bcc_ptr - (unsigned long)smb_buf, 2)) {
> ++bcc_ptr;
> --bytes_remaining;
> }
> diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
> index b83f59051b26..4eefbe574b82 100644
> --- a/fs/cifs/smb2inode.c
> +++ b/fs/cifs/smb2inode.c
> @@ -207,7 +207,7 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
> rqst[num_rqst].rq_iov = &vars->si_iov[0];
> rqst[num_rqst].rq_nvec = 1;
>
> - size[0] = 1; /* sizeof __u8 See MS-FSCC section 2.4.11 */
> + size[0] = sizeof(u8); /* See MS-FSCC section 2.4.11 */
> data[0] = &delete_pending[0];
>
> rc = SMB2_set_info_init(tcon, server,
> @@ -225,7 +225,7 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
> rqst[num_rqst].rq_iov = &vars->si_iov[0];
> rqst[num_rqst].rq_nvec = 1;
>
> - size[0] = 8; /* sizeof __le64 */
> + size[0] = sizeof(__le64);
> data[0] = ptr;
>
> rc = SMB2_set_info_init(tcon, server,
> diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
> index d73e5672aac4..258b01306d85 100644
> --- a/fs/cifs/smb2misc.c
> +++ b/fs/cifs/smb2misc.c
> @@ -248,7 +248,7 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *server)
> * Some windows servers (win2016) will pad also the final
> * PDU in a compound to 8 bytes.
> */
> - if (((calc_len + 7) & ~7) == len)
> + if (ALIGN(calc_len, 8) == len)
> return 0;
>
> /*
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 6352ab32c7e7..5da0b596c8a0 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -466,15 +466,14 @@ build_signing_ctxt(struct smb2_signing_capabilities *pneg_ctxt)
> /*
> * Context Data length must be rounded to multiple of 8 for some servers
> */
> - pneg_ctxt->DataLength = cpu_to_le16(DIV_ROUND_UP(
> - sizeof(struct smb2_signing_capabilities) -
> - sizeof(struct smb2_neg_context) +
> - (num_algs * 2 /* sizeof u16 */), 8) * 8);
> + pneg_ctxt->DataLength = cpu_to_le16(ALIGN(sizeof(struct smb2_signing_capabilities) -
> + sizeof(struct smb2_neg_context) +
> + (num_algs * sizeof(u16)), 8));
> pneg_ctxt->SigningAlgorithmCount = cpu_to_le16(num_algs);
> pneg_ctxt->SigningAlgorithms[0] = cpu_to_le16(SIGNING_ALG_AES_CMAC);
>
> - ctxt_len += 2 /* sizeof le16 */ * num_algs;
> - ctxt_len = DIV_ROUND_UP(ctxt_len, 8) * 8;
> + ctxt_len += sizeof(__le16) * num_algs;
> + ctxt_len = ALIGN(ctxt_len, 8);
> return ctxt_len;
> /* TBD add SIGNING_ALG_AES_GMAC and/or SIGNING_ALG_HMAC_SHA256 */
> }
> @@ -511,8 +510,7 @@ build_netname_ctxt(struct smb2_netname_neg_context *pneg_ctxt, char *hostname)
> /* copy up to max of first 100 bytes of server name to NetName field */
> pneg_ctxt->DataLength = cpu_to_le16(2 * cifs_strtoUTF16(pneg_ctxt->NetName, hostname, 100, cp));
> /* context size is DataLength + minimal smb2_neg_context */
> - return DIV_ROUND_UP(le16_to_cpu(pneg_ctxt->DataLength) +
> - sizeof(struct smb2_neg_context), 8) * 8;
> + return ALIGN(le16_to_cpu(pneg_ctxt->DataLength) + sizeof(struct smb2_neg_context), 8);
> }
>
> static void
> @@ -557,18 +555,18 @@ assemble_neg_contexts(struct smb2_negotiate_req *req,
> * round up total_len of fixed part of SMB3 negotiate request to 8
> * byte boundary before adding negotiate contexts
> */
> - *total_len = roundup(*total_len, 8);
> + *total_len = ALIGN(*total_len, 8);
>
> pneg_ctxt = (*total_len) + (char *)req;
> req->NegotiateContextOffset = cpu_to_le32(*total_len);
>
> build_preauth_ctxt((struct smb2_preauth_neg_context *)pneg_ctxt);
> - ctxt_len = DIV_ROUND_UP(sizeof(struct smb2_preauth_neg_context), 8) * 8;
> + ctxt_len = ALIGN(sizeof(struct smb2_preauth_neg_context), 8);
> *total_len += ctxt_len;
> pneg_ctxt += ctxt_len;
>
> build_encrypt_ctxt((struct smb2_encryption_neg_context *)pneg_ctxt);
> - ctxt_len = DIV_ROUND_UP(sizeof(struct smb2_encryption_neg_context), 8) * 8;
> + ctxt_len = ALIGN(sizeof(struct smb2_encryption_neg_context), 8);
> *total_len += ctxt_len;
> pneg_ctxt += ctxt_len;
>
> @@ -595,9 +593,7 @@ assemble_neg_contexts(struct smb2_negotiate_req *req,
> if (server->compress_algorithm) {
> build_compression_ctxt((struct smb2_compression_capabilities_context *)
> pneg_ctxt);
> - ctxt_len = DIV_ROUND_UP(
> - sizeof(struct smb2_compression_capabilities_context),
> - 8) * 8;
> + ctxt_len = ALIGN(sizeof(struct smb2_compression_capabilities_context), 8);
> *total_len += ctxt_len;
> pneg_ctxt += ctxt_len;
> neg_context_count++;
> @@ -780,7 +776,7 @@ static int smb311_decode_neg_context(struct smb2_negotiate_rsp *rsp,
> if (rc)
> break;
> /* offsets must be 8 byte aligned */
> - clen = (clen + 7) & ~0x7;
> + clen = ALIGN(clen, 8);
> offset += clen + sizeof(struct smb2_neg_context);
> len_of_ctxts -= clen;
> }
> @@ -2413,7 +2409,7 @@ create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
> unsigned int group_offset = 0;
> struct smb3_acl acl;
>
> - *len = roundup(sizeof(struct crt_sd_ctxt) + (sizeof(struct cifs_ace) * 4), 8);
> + *len = round_up(sizeof(struct crt_sd_ctxt) + (sizeof(struct cifs_ace) * 4), 8);
>
> if (set_owner) {
> /* sizeof(struct owner_group_sids) is already multiple of 8 so no need to round */
> @@ -2487,7 +2483,7 @@ create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
> memcpy(aclptr, &acl, sizeof(struct smb3_acl));
>
> buf->ccontext.DataLength = cpu_to_le32(ptr - (__u8 *)&buf->sd);
> - *len = roundup(ptr - (__u8 *)buf, 8);
> + *len = round_up((unsigned int)(ptr - (__u8 *)buf), 8);
>
> return buf;
> }
> @@ -2581,7 +2577,7 @@ alloc_path_with_tree_prefix(__le16 **out_path, int *out_size, int *out_len,
> * final path needs to be 8-byte aligned as specified in
> * MS-SMB2 2.2.13 SMB2 CREATE Request.
> */
> - *out_size = roundup(*out_len * sizeof(__le16), 8);
> + *out_size = round_up(*out_len * sizeof(__le16), 8);
> *out_path = kzalloc(*out_size + sizeof(__le16) /* null */, GFP_KERNEL);
> if (!*out_path)
> return -ENOMEM;
> @@ -2687,20 +2683,17 @@ int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
> uni_path_len = (2 * UniStrnlen((wchar_t *)utf16_path, PATH_MAX)) + 2;
> /* MUST set path len (NameLength) to 0 opening root of share */
> req->NameLength = cpu_to_le16(uni_path_len - 2);
> - if (uni_path_len % 8 != 0) {
> - copy_size = roundup(uni_path_len, 8);
> - copy_path = kzalloc(copy_size, GFP_KERNEL);
> - if (!copy_path) {
> - rc = -ENOMEM;
> - goto err_free_req;
> - }
> - memcpy((char *)copy_path, (const char *)utf16_path,
> - uni_path_len);
> - uni_path_len = copy_size;
> - /* free before overwriting resource */
> - kfree(utf16_path);
> - utf16_path = copy_path;
> + copy_size = round_up(uni_path_len, 8);
> + copy_path = kzalloc(copy_size, GFP_KERNEL);
> + if (!copy_path) {
> + rc = -ENOMEM;
> + goto err_free_req;
> }
> + memcpy((char *)copy_path, (const char *)utf16_path, uni_path_len);
> + uni_path_len = copy_size;
> + /* free before overwriting resource */
> + kfree(utf16_path);
> + utf16_path = copy_path;
> }
>
> iov[1].iov_len = uni_path_len;
> @@ -2826,9 +2819,7 @@ SMB2_open_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
> uni_path_len = (2 * UniStrnlen((wchar_t *)path, PATH_MAX)) + 2;
> /* MUST set path len (NameLength) to 0 opening root of share */
> req->NameLength = cpu_to_le16(uni_path_len - 2);
> - copy_size = uni_path_len;
> - if (copy_size % 8 != 0)
> - copy_size = roundup(copy_size, 8);
> + copy_size = round_up(uni_path_len, 8);
> copy_path = kzalloc(copy_size, GFP_KERNEL);
> if (!copy_path)
> return -ENOMEM;
> @@ -4090,7 +4081,7 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
> if (request_type & CHAINED_REQUEST) {
> if (!(request_type & END_OF_CHAIN)) {
> /* next 8-byte aligned request */
> - *total_len = DIV_ROUND_UP(*total_len, 8) * 8;
> + *total_len = ALIGN(*total_len, 8);
> shdr->NextCommand = cpu_to_le32(*total_len);
> } else /* END_OF_CHAIN */
> shdr->NextCommand = 0;
> --
> 2.35.3
>
