Killing the Big Kernel Lock
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From: Frederic Weisbecker on 8 Apr 2010 17:40 On Thu, Apr 08, 2010 at 11:27:26PM +0200, Arnd Bergmann wrote: > On Thursday 08 April 2010 22:45:45 Jan Blunck wrote: > > On Sun, Mar 28, Arnd Bergmann wrote: > > > > General thoughts: > > > > > > > > ".llseek = NULL," so far meant "do the Right Thing on lseek() and > > > > friends, as far as the fs core can tell". Shouldn't we keep it that > > > > way? It's as close to other ".method = NULL," as it can get, which > > > > either mean "silently skip this method if it doesn't matter" (e.g. > > > > .flush) or "fail attempts to use this method with a fitting errno" (e.g. > > > > .write). > > > > > > My series changes the default from 'default_llseek' to 'generic_file_llseek', > > > > That is not that easy. generic_file_llseek() is testing against 'offset < > > inode->i_sb->s_maxbytes'. This is not necessarily true when you think about > > directories with random offset cookies. I know that seeking on directories is > > stupid but don't blame me. > > Oh, I see. Would it work if we extend generic_file_llseek to only check s_maxbytes > if S_ISREG(inode->i_mode)))? > > > > Yes, that also sounds like a good idea. I believe that Jan actually posted > > > a patch to do that at some point. > > > > Yes, it is in > > > > http://git.infradead.org/users/jblunck/linux-2.6.git bkl/default-lseek > > > > There are some other patches in that branch that are not upstream yet. Mind to > > take them for your bkl-removal branch? > > Frederic is now collecting the new patches. Your default-lseek series looks > good to me, except for the obvious one that says 'FIXME' in the subject. > > Maybe Frederic can add your series except for that one as another branch to > get pulled into his kill-the-bkl master branch. Ok, will have a look at this soon (I will also put a branch for the procfs series). Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Jan Blunck on 9 Apr 2010 07:10 On Thu, Apr 08, Arnd Bergmann wrote: > On Thursday 08 April 2010 22:45:45 Jan Blunck wrote: > > On Sun, Mar 28, Arnd Bergmann wrote: > > > > General thoughts: > > > > > > > > ".llseek = NULL," so far meant "do the Right Thing on lseek() and > > > > friends, as far as the fs core can tell". Shouldn't we keep it that > > > > way? It's as close to other ".method = NULL," as it can get, which > > > > either mean "silently skip this method if it doesn't matter" (e.g. > > > > .flush) or "fail attempts to use this method with a fitting errno" (e.g. > > > > .write). > > > > > > My series changes the default from 'default_llseek' to 'generic_file_llseek', > > > > That is not that easy. generic_file_llseek() is testing against 'offset < > > inode->i_sb->s_maxbytes'. This is not necessarily true when you think about > > directories with random offset cookies. I know that seeking on directories is > > stupid but don't blame me. > > Oh, I see. Would it work if we extend generic_file_llseek to only check s_maxbytes > if S_ISREG(inode->i_mode)))? > Yes and maybe rename generic_file_llseek to generic_llseek. Jan > > > Yes, that also sounds like a good idea. I believe that Jan actually posted > > > a patch to do that at some point. > > > > Yes, it is in > > > > http://git.infradead.org/users/jblunck/linux-2.6.git bkl/default-lseek > > > > There are some other patches in that branch that are not upstream yet. Mind to > > take them for your bkl-removal branch? > > Frederic is now collecting the new patches. Your default-lseek series looks > good to me, except for the obvious one that says 'FIXME' in the subject. > > Maybe Frederic can add your series except for that one as another branch to > get pulled into his kill-the-bkl master branch. > > Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Stefan Richter on 10 Apr 2010 11:20
On 27 Mar, Arnd Bergmann wrote: > On Saturday 27 March 2010 00:47:33 Stefan Richter wrote: >> firewire-core and raw1394 do not actually require the BKL, they only >> miss to declare their files as not seekable. I will post patches which >> change these accordingly. > > Your patches look good, but it would be helpful to also set .llseek = no_llseek > in the file operations, because that is much easier to grep for than > only the nonseekable_open. While it's technically a NOP on the presence of > nonseekable_open, it will help that I don't accidentally apply my patch on > top of yours. I pushed modified versions of these patches out to linux1394-2.6.git now (master and for-next branch, on top of unrelated firewire updates). They contain the explicit .llseek = no_llseek now. http://git.kernel.org/?p=linux/kernel/git/ieee1394/linux1394-2.6.git;a=commitdiff;h=3ac26b2ee30005930117fe6a180c139c5f300faf http://git.kernel.org/?p=linux/kernel/git/ieee1394/linux1394-2.6.git;a=commitdiff;h=7cfe21aae155c26193fde617dc61d37a79a63f86 -- Stefan Richter -=====-==-=- -=-- -=-=- http://arcgraph.de/sr/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |