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Fri, 9 Oct 2020 21:34:38 +0000 (UTC) Received: from sol.localdomain (172-10-235-113.lightspeed.sntcca.sbcglobal.net [172.10.235.113]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 44F7C21D6C; Fri, 9 Oct 2020 21:34:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602279277; bh=af4HYKUXjfzQEnpRkoqrLOtb/VuZgD2GaaA85DESAB8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mAKgXcy5CifgRYN2i2C2c94+Jg5oLVaoZk49jTIFxseeqdMtEOOqP5cL66hXhKNTI eNSQDBkgqgAc1Wd7XIXje+joGiBVI4yatMIDb1+kpBlSLeGvwRiFFGcw+A+0IeryZM wi38bfOOqpr1rBlahq6SJoGGKG4xvvKCLXOhXA9s= Date: Fri, 9 Oct 2020 14:34:34 -0700 From: Eric Biggers To: ira.weiny@intel.com Cc: Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra , linux-aio@kvack.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-mmc@vger.kernel.org, Dave Hansen , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, target-devel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-kselftest@vger.kernel.org, samba-technical@lists.samba.org, ceph-devel@vger.kernel.org, drbd-dev@lists.linbit.com, devel@driverdev.osuosl.org, linux-cifs@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-scsi@vger.kernel.org, linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, x86@kernel.org, amd-gfx@lists.freedesktop.org, linux-afs@lists.infradead.org, cluster-devel@redhat.com, linux-cachefs@redhat.com, intel-wired-lan@lists.osuosl.org, xen-devel@lists.xenproject.org, linux-ext4@vger.kernel.org, Fenghua Yu , ecryptfs@vger.kernel.org, linux-um@lists.infradead.org, intel-gfx@lists.freedesktop.org, linux-erofs@lists.ozlabs.org, reiserfs-devel@vger.kernel.org, linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, Jaegeuk Kim , Dan Williams , io-uring@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, netdev@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-btrfs@vger.kernel.org Subject: Re: [PATCH RFC PKS/PMEM 22/58] fs/f2fs: Utilize new kmap_thread() Message-ID: <20201009213434.GA839@sol.localdomain> References: <20201009195033.3208459-1-ira.weiny@intel.com> <20201009195033.3208459-23-ira.weiny@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201009195033.3208459-23-ira.weiny@intel.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Oct 09, 2020 at 12:49:57PM -0700, ira.weiny@intel.com wrote: > From: Ira Weiny > > The kmap() calls in this FS are localized to a single thread. To avoid > the over head of global PKRS updates use the new kmap_thread() call. > > Cc: Jaegeuk Kim > Cc: Chao Yu > Signed-off-by: Ira Weiny > --- > fs/f2fs/f2fs.h | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index d9e52a7f3702..ff72a45a577e 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -2410,12 +2410,12 @@ static inline struct page *f2fs_pagecache_get_page( > > static inline void f2fs_copy_page(struct page *src, struct page *dst) > { > - char *src_kaddr = kmap(src); > - char *dst_kaddr = kmap(dst); > + char *src_kaddr = kmap_thread(src); > + char *dst_kaddr = kmap_thread(dst); > > memcpy(dst_kaddr, src_kaddr, PAGE_SIZE); > - kunmap(dst); > - kunmap(src); > + kunmap_thread(dst); > + kunmap_thread(src); > } Wouldn't it make more sense to switch cases like this to kmap_atomic()? The pages are only mapped to do a memcpy(), then they're immediately unmapped. - Eric