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This patch adds early checks to avoid burning CPU cycles on the assembly of trace entries which would be skipped anyway. Introduce a static const variable to keep the trace level to check with debug_level_enabled() in sync with the actual trace emit with debug_event(). In order not to refactor the SAN tracing too much, simply use a define instead. This change is only for the non / semi hot paths, while the actual (I/O) hot path was already improved earlier: zfcp_dbf_scsi() is already guarded by its only caller _zfcp_dbf_scsi() since commitdcd20e2316("[SCSI] zfcp: Only collect SCSI debug data for matching trace levels"). zfcp_dbf_hba_fsf_res() is already guarded by its only caller zfcp_dbf_hba_fsf_response() since commit2e261af84c("[SCSI] zfcp: Only collect FSF/HBA debug data for matching trace levels"). Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> [maier@linux.vnet.ibm.com: rebase, reword, default level 3 branch prediction] Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com> Signed-off-by: Benjamin Block <bblock@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.